Blueberries

Blueberries

Growing Blueberries

The following is a general guide to blueberry management based upon plant and pest development. The suggested timing will vary according to blueberry variety, weather and location. The actions are for established plantings except where otherwise noted.

Timing Type of Action Action
JANUARY / FEBRUARY
Plants dormant
Plants Dormant
Plant Care
  • Prune beginning after leaf drop. Be sure to remove diseased and dead wood.
Disease Control
  • Apply controls for bacterial blight. For mummy berry control, watch for development stage when leaf buds show 5 mm of green tissue. Also check for open mummyberry cups. Prepare to spray fungicide, as required. (February/March)
Insect Control
  • Check for scale and apply dormant oil and/or lime sulfur spray by mid-February (before bud break), if required. Also helps to control leafroller, spanworm, wintermoth eggs and larvae.
Weed Control
  • Apply pre-emergent herbicides before weed growth starts.
Other
  • Ensure sprayers are tuned-up and calibrated.
MARCH
Buds start to swell
Buds start to swell
Plant Care
  • New plantings. Begin land preparation for fall or next spring plantings.
Disease Control
  • Continue to check growth of leaf buds for mummyberry susceptibility. Apply fungicides to protect developing buds from mummy berry as necessary at critical growth stage. Apply controls for root rot, if required.
  • Apply copper oxychloride for bacterial blight, as necessary.
Soil Care
  • Seed grasses for permanent cover between rows when soil can be worked. Apply sawdust mulch to beds, if needed.
Weed Control
  • Apply pre-emergent herbicides before weed growth starts if not applied earlier.
Food Safety
  • Ensure a food safety plan is in place including a record keeping system.
LATE MARCH TO LATE APRIL
Leaf and flower bud break
Leaf and flower bud break
Plant Care
  • Make first fertilizer application (mid April).
  • New plantings. Set out new plants as conditions permit (up to mid May).
Disease Control
  • Continue to apply fungicide for primary mummyberry control, as required.
  • Apply copper oxychloride for bacterial blight, if necessary. If not done earlier, apply controls for root rot, if required.
Insect Control
  • Apply recommended prebloom insecticides to control aphids and minimize spread of blueberry scorch virus. Start weekly checks of swelling blossom buds for hatching spanworm, winter moth (late March), and caterpillars blown to fields from outside areas. Apply controls as needed. Start weekly checks for leafrollers, looking at blossom clusters and rolled leaves.
Weed Control
  • Control weeds by cultivation and/or herbicides. Apply herbicides for quackgrass and other perennial weed control.
Other Pests
  • Watch for snails and slugs - control as required.
Soil Care
  • Seed grasses for permanent cover between rows if not done earlier. Apply sawdust mulch, if needed and not done earlier.
LATE APRIL/MAY
Blossoming
Blossoming
Blossoming
Plant Care
  • Place bee hives in field when 10% of blossoms are open. Protect hives from bears where necessary. Remove hives from fields when blossoming is over.
Disease Control
  • Monitor all fields for symptoms of blueberry scorch and blueberry shock. Watch for mummy berry infections on flowers and shoots and apply fungicides if needed. Apply fungicides for Botrytis blight and/or Anthracnose (fruit rots) if wet weather is anticipated.
Insect Control
  • Continue to watch for leafrollers and control as needed. Monitor for aphids. Control aphids after bloom is finished and bees have been removed from the field. Apply sprays only if predator numbers are low and aphids are increasing.
Weed Control
  • Cultivate for weed control in row middles or mow cover crop, as appropriate. Apply directed treatments of non-residual herbicides, if needed, observing days to harvest interval.
Soil Care
  • Watch for poorly drained areas in fields. Plan fall drainage improvements.
Food Safety
  • Test irrigation and spray water for E. coli and fecal coliforms. Order toilets, hand washing units and other sanitary supplies.
JUNE
Fruit development
Fruit Development
Plant Care
  • Make second fertilizer applications up to mid-June. Irrigate as necessary.
Disease Control
  • Apply fungicides for Botrytis (fruit rot) and Anthracnose (ripe rot) if weather is wet during the fruit development period. Monitor for root rot symptoms and apply controls if necessary.
Insect Control
  • Continue to watch for leafrollers and spanworms to late June, control as needed. Continue to monitor for aphids especially in scorch infected fields. Control as required.
    Prune out and destroy branches with tent caterpillars before end of June when caterpillars leave the nest.
Weed Control
  • Cultivate for weed control in row middles or mow cover crop, as appropriate. Apply directed treatments of non-residual herbicides, if needed. Observe pre-harvest intervals.
Other Pests
  • Prepare bird predation management plan. Install bird control devices or erect bird netting.
Soil Care
  • New plantings. Start to prepare land for new fall plantings.
Food Safety
  • Place portable toilets and hand washing units. Ensure workers are trained in good hygiene and harvesting practices.
JULY
Fruit development and ripening
Fruit development and ripening
Plant Care
  • Monitor soil moisture and irrigate as necessary.
Disease Control
  • Sample berries from each field and store at room temperature to assess fruit rot levels. Monitor for root rot symptoms and mark affected areas. Apply root rot controls if necessary.
Insect Control
  • Continue to monitor insect pests, control only if needed. • Monitor for spotted wing Drosophila (SWD) and apply protective sprays after fruit ripens.
Other Pests
  • Install bird control devices, or erect bird netting if not done earlier.
JULY - SEPTEMBER
Harvesting
Harvesting
Plant Care
  • Harvest and market fruit. Collect plant tissue samples (mid July to mid August) for nutrient analysis. Irrigate as needed.
Disease Control
  • Continue to apply fungicides for Botrytis, Anthracnose, and other fruit rot diseases, if weather is wet. Observe days to harvest interval. Prune out branches killed by Godronia canker (red flagging) or bacterial blight and destroy.
Insect Control
  • Continue to apply protective sprays to control spotted wing Drosophila. Apply insecticides to control aphids and young scale if required. Observe pre- harvest intervals. Prune out and destroy branches with tent caterpillars (from mid July). Watch for scale "crawlers" from late July to August and control if needed.
Other Pests
  • Control birds following approved guidelines.
Soil Care
  • Continue to mow cover crop as needed.
  • New plantings. Install drainage, if needed. Monitor soil pH and adjust as necessary. Incorporate sawdust or compost in planting beds as required.
SEPTEMBER
Post harvest growth
Plant Care
  • Irrigate as necessary.
Disease Control
  • Apply controls for bacterial blight before fall rains start. Prune out diseased wood.
Insect Control
  • Prune out and destroy caterpillar tents before mid September when caterpillars drop to the ground for the winter.
Other Pests
  • Remove bird control devices and netting after harvest.
Soil Care
  • Take soil samples for analysis, if needed. Check pH of soil. Apply calcium and magnesium in form of dolomite or sulphur if required. Subsoil between rows when soil is dry, if necessary. Seed grasses for permanent cover between rows.
  • New plantings. Install drainage, if required and not done earlier.
OCTOBER
Post harvest growth
Plant Care
  • Continue to prune out and remove diseased wood.
  • New plantings. Set out new plants. Best time to plant container stock in coastal areas.
Disease Control
  • Apply controls forbacterial blight (total 2 sprays in fall).
Other Pests
  • Check for field mice activity and apply bait, if required.
Soil Care
  • Check pH of soil and apply lime or sulfur, if required. Subsoil between rows when soil is dry, if necessary. Install or improve drainage, as required. Mow cover crop, if required.
Weed Control
  • Monitor weeds. Apply herbicides for grass control, according to label directions.
Other
  • Flush irrigation systems and sprayers to protect against winter damage.
NOVEMBER / DECEMBER
Plants dormant
Plant Care
  • Apply sawdust mulch, if necessary. Order bees for the coming season.
Weed Control
  • Apply Roundup for grass control if not done earlier.
Other Pests
  • Watch for field mice activity and apply bait if needed.

Site Selection

With good soil and climatic conditions, and proper management, blueberries can remain productive for many years. There are productive south-coastal plantings that are over 50 years old. Consider the following when selecting and preparing sites for blueberries.

Soil

A soil test should be used to determine the nutrient status and soil pH before setting out a new planting. Have the soil tested at least 6 months before planting so that any amendments can be added as the field is prepared. Take soil samples from the top 30 cm (0 to 12 in). Consult a soil laboratory (for laboratory listings, refer to the BCAGRI publication, "Resources for Berry Growers") or contact the BCAGRI for a factsheet on soil sampling.

In south-coastal B.C., blueberries have traditionally been grown on highly organic soils with an organic matter content of 20 to 50% (muck soils). However, they can also be grown successfully on mineral soils such as silt or sandy loam. Blueberries do not perform well in wet soils or heavy, poorly-structured clay soils.

Blueberries do best in acid soil with a pH range of 4.5 to 5.2. A pH outside this range can result in poor growth and low yields. See "Site Preparation" section of this guide to amend pH.

Drainage

Blueberries are relatively shallow-rooted and have fine, thread-like roots which require an open, porous soil. They require soils that drain well throughout the year and hold adequate moisture for good plant growth during the summer months.

Plants cannot tolerate extended periods of flooding especially when they are actively growing. Poorly drained soil can result in poor plant growth, poor yield, root rot and plant death. A water table maintained at least 60 cm (24 in) below the soil surface is best for blueberry production.

Irrigation and Water Quality

Most of the blueberry roots that take up nutrients and water are in the upper 40 cm (16 in) of soil and within the dripline of the bush. A uniform and adequate supply of moisture is essential for good growth and yields of quality fruit. In the south coast region of B.C., rainfall is generally inadequate in July and August and supplemental irrigation is necessary.

To determine actual crop water requirements and irrigation schedules, such factors as temperature, humidity, soil type, crop age and health, stage of crop development and presence or absence of mulch must be considered.

Moisture demand is particularly great during fruit development - mature crops may require 2.5 to 4 cm or more of water per week. Moisture detection devices such as tensiometers or gypsum blocks can be used to help determine irrigation requirement. Local research is underway which will provide better information to develop accurate irrigation scheduling.

In the past, most blueberry crops in B.C. were irrigated with sprinklers, but presently most young fields are established with drip or trickle irrigation. Drip irrigation is more efficient as water is delivered directly to the root zone providing more consistent and even soil moisture. Fertilizers can also be injected into the irrigation water.

The system must be designed with an emitter output and spacing to provide uniform moisture distribution. Because drip is so convenient, there is a tendency for some growers to apply more water than the crop needs which may lead to fruit quality problems and encourage the development of root rot.

It is very important to check the quality of available irrigation water before planting or installing an irrigation system. Water should have a low salt content (less than 700 TDS or an EC less than 1.2) and a low pH (less than 6.0). Ditch water may contain high levels of fecal coliforms which could contaminate fruit if overhead irrigated before harvest. Water high in iron may stain fruit causing it to be downgraded and unsuitable for fresh market sales. Refer to the Water Management section of this guide for more information.

Contact a laboratory for the best way to collect water samples for testing (for laboratory listings, refer to BCAGRI publication, "Resources for Berry Growers"). Contaminants in the water may be removed with filters to enable overhead irrigation. However, filters which remove iron, can be costly. Ultraviolet (UV) treatment systems can be used to eliminate fecal coliforms.

If poor quality water must be used, use an irrigation system that will not put water in contact with fruit. In some fields, controlled drainage or sub-irrigation can partially or fully substitute for an irrigation system. Micro jet or drip systems apply water to the base of the plants, thus avoiding contact with the fruit. Micro jet systems have larger orifices than drip systems and provide better water distribution and are less likely to plug.

Site Preparation

This is a critical step to successful planting. Start to prepare the field for planting the year before. Consider the following:

Wireworm Control

Check for wireworms in sites previously planted in grass. Plan for control. See "Wireworms" section in the Berry Production Guide: Pest Management (PDF).

Nematode Control

High nematode populations can contribute to poor growth and establishment of young plantings, particularly on sandy soils. Some nematode species (dagger) can transmit viruses such as tomato ringspot.

Submit a soil sample to a laboratory for a nematode test. If fumigation is required it is best done in early fall. For more information, see "Nematodes" section of the Berry Production Guide: Pest Management (PDF).

Weed Control

Control established perennial weeds such as quackgrass, buttercup, horsetail and Canada thistle before planting.

Drainage

Install a drainage system before planting, especially in areas with poorly drained soils. Sub-surface drainage pipes are installed 0.8 to 1.2 m (2.5 to 4 ft) below the soil surface. If irrigation water quality is poor, the site conditions may allow for the drainage system to be used for controlled drainage or sub-irrigation. Refer to the "BC Agricultural Drainage Manual" for more information. Drainage systems work only as well as they are designed, installed and maintained.

Use management practices that promote good drainage. Raised beds help to overcome problems with high water tables but are not a substitute for a drainage system. Other ways to promote good drainage include: incorporating a small amount of sawdust in the beds before planting, covering raised beds with sawdust mulch, cover cropping between the rows, and periodically sub-soiling in the wheel tracks of harvesters or tractors.

Field Layout

Fields should be designed for mechanical harvesting to allow flexibility in future harvesting decisions. Mechanical harvesting requires a minimum of 3 m (10 ft) between the rows. Provide a 4.5 to 5.0 m (15 to 16 ft) wide row break every 125 m (400 ft) for unloading harvesters and other machinery. Most harvesters require 7.6 to 9.0 m (25 to 30 ft) at the ends of rows (headlands) to turn around.

The risers or posts for overhead irrigation should be no higher than 2.1 m (7 ft) and placed in the center of the row.

Plant on raised beds to reduce fruit drop when harvesting mechanically. Beds place the catcher plates nearer to the narrow base of the plant, keeping them in close contact resulting in less fruit drop. Build the beds 20 cm (8 in) high and 120 cm (4 ft) wide at the base. Raised beds are beneficial for plant growth regardless of harvesting method, especially in fields that are slower to drain. Bushes planted on raised beds, however, will dry out more quickly in the summer and require more frequent irrigation.

Soil Amendments

pH

Check and adjust soil pH before planting and every 3 to 4 years after planting. The optimum pH for blueberries is 4.5 to 5.2. Soil pH below 4.0 can be raised by adding dolomite or ground limestone at 2 to 4 tonne/ha (1 to 2 t/acre). Soil pH above 5.5 can be lowered with elemental sulfur. To lower the pH of a loam soil from 6.0 to 5.0 incorporate about 1.75 tonne/ha (1500 lb/acre) of elemental sulfur (flour or prilled sulfur) into the soil several months before planting. If pH is over 6.0 higher rates of sulfur and more time will be required. Sawdust, incorporated into the soil when beds are formed, lowers the soil pH slightly, and also increases the organic matter content.

Phosphorus (P) and potassium (K) do not move readily in the soil. In new plantings, broadcast and incorporate required P and K (as determined by a soil test) in the bed before planting.

Manure and Compost

Manure and compost are valuable sources of crop nutrients and organic matter. They contain nitrogen, phosphorus, potassium, calcium and several micro-nutrients which are required by blueberries. Manure can be used prior to planting as a partial source of nitrogen, but timing application and balancing with other sources of nutrients is essential. Compost should only be used as a partial source of nitrogen in the planting year. High rates of compost or manure may contribute to an undesirable rise in soil pH. Refer to the "Manure Use" section of the Berry Production Guide: Nutrient Management (PDF).

Sawdust

On heavy clay soils or very sandy soils, plants may benefit from the incorporation of sawdust into the beds before planting. However, research in Oregon has shown that for friable, loam soils, there is no short-term benefit from the practice and that growth may even be restricted. Before transplanting on heavy or sandy soils, apply a 5 to 10 cm (2 to 4 in) layer of sawdust over the planting bed and incorporate into the top 15 to 20 cm (6 to 8 in). Build raised beds after the sawdust is incorporated.

Any woodwaste containing high levels of bark, especially hog fuel, should be checked for salts.

Planting

Plant Source

Several serious diseases such as blueberry scorch virus can be introduced to the field on planting stock. Purchase plants only from reputable nurseries where propagation is done according to an accepted protocol which includes isolation, aphid management and testing for scorch, shock and other viruses.

Spacing

Between Rows

See "Field Layout" section of this guide.

Between Plants

The most commonly used in-row spacing is 90 cm. Research in Oregon has shown that varieties such as Duke and Bluecrop can be planted as close as 45 cm and will benefit with higher yields in the early life of the planting. However, more pruning labour may be necessary when the field is mature.

Table 1. Plant requirements at different spacings
Distance between Plants (Metres) Distance between Rows (Metres) Number of Plants Required (Hectare) Number of Plants Required (Acre)
0.6 2.7 6173 2469
0.9 2.7 4115 1646
1.2 2.7 3086 1235
0.6 3 5556 2222
0.9 3 3704 1481
1.2 3 2778 1111
0.6 3.3 5051 2020
0.9 3.3 3367 1347
1.2 3.3 2525 1010

Planting

Planting can be done in the fall or spring. However, in colder areas, spring planting is preferred to avoid losses due to frost heaving. In coastal areas, fall planting may allow quicker plant establishment.

Generally, two year old nursery-grown plants are used to establish a planting. Ensure that root balls are thoroughly wetted prior to planting. When planting container-grown plants, inspect the roots and if pot-bound break apart the root ball before planting. This stimulates root growth and breaks the circling pattern of root growth that often develops. This is especially important if plants have been grown in pots longer than three years.

Drawing of a blueberry plant

Set plants at the depth they were planted in the pot or nursery. If planted too deep, roots and crown may be deprived of oxygen resulting in plant death especially in heavier soils. Fill in the soil and press firmly around the plant to maximize soil-root contact.

After planting remove the low, weak twiggy growth at the base of the plant, leaving the strong healthy canes. Irrigate after planting if required.

Strip off flower buds in the establishment year and in the second growing season to encourage plants to develop strong roots and a good framework of canes for future fruit production.

Fertilizing

No fertilizer should be put in the planting holes. Plants set out in the fall should not receive any fertilizer until the following spring. Fertilize plants set out in the spring 3 to 4 weeks after planting. Two or more applications may be required through the first growing season. With young plants it is best to apply only small amounts at a time. If sawdust mulch is used, more fertilizer will be required to make up for the nitrogen taken up by the decomposing sawdust.

Use caution when fertilizing young plants. Keep fertilizer about 10 cm (4 in) from the base of the plant. Spread fertilizer thinly and evenly to slightly beyond the dripline. Do not fertilize when the soil is dry. Refer to "Nutrition" in "Established Plantings" for further details and rates.

Drawing of a blueberry plant

Sawdust Mulches

Mulching keeps the soil cool, aids in water conservation, increases organic matter in the soil, improves soil structure and helps control annual weeds. Blueberries often grow more vigorously and produce better yields if they are mulched. Apply 5 to 8 cm (2 to 3 in) of sawdust to the surface of the bed the first year and every 2 to 3 years to maintain the mulch. The roots tend to grow into the mulch so as it decomposes the plant roots may become exposed if the sawdust layer is not maintained.

Microbial activity, which decomposes the sawdust, takes nitrogen from the soil. Nitrogen application rates may need to be increased by 30kg/ha (12 kg/acre) in the first few years if sawdust is used.

Several types of sawdust, including fir, hemlock and alder, have been successfully used on blueberries. Traditionally, cedar sawdust has been avoided because of concerns that its oil leachate may injure the crop. In recent years, because of a shortage of other types, some growers have applied cedar sawdust with no apparent negative affects.

Any woodwaste containing high levels of bark, especially hog fuel, should be checked for salts.

The use of sawdust is an acceptable practice under the Agricultural Environment Management Code of Practice. Wood residue must be stored or applied at least 15 metres from away from a water course, and can not be applied more than 30 centimetres deep. Refer to the Agricultural Environmental Management Code of Practice for more information.

Trellising for Mechanical Harvesting

Many varieties are successfully picked by over-the-row self-propelled harvesters (see recommended varieties). Most varieties require a trellis system to hold the branches in an upright position during harvesting. Trellising will also allow for better equipment access for late season sprays for Spotted Wing Drosophila.

This system can be put in place the year before machine harvesting begins. Wood posts used for trellising should be treated to extend their life. Posts should be 64 to 76 cm (25 to 30 in) in height and spaced 5.5 to 7 m (18 to 23 ft) apart. Use high tensile, 12 gauge, triple galvanized wire. Use wire or wood cross members to prevent the wires from spreading under heavy fruit loads. Spacing between wires and the distance from the ground will differ between varieties. Wires for Bluecrop are commonly spaced 45 to 50 cm (18 to 20 in) apart and 0.6 m (25 in) high.

Weeds

Good weed control is critical, especially in the establishment years, as weeds compete with the crop for water, light and nutrients and can seriously limit growth. Weeds can also provide shelter for field mice and encourage certain insects and diseases.

Prior to planting it is critical to control existing perennial weeds and brush. Glyphosate formulations such as Roundup or Touchdown effectively control tough weeds without leaving a soil residue.

Sawdust mulch will help to suppress annual weeds, but herbicides will also be necessary. Select a combination of herbicide treatments from the following pages based on soil type and knowledge of the major problem weeds in the field.

Do not apply residual herbicides such as Velpar, Sinbar, Chateau and simazine until plants become well established (6 months to a year after planting).

Note: Herbicide application rates are listed on pesticide labels and in the production guide for broadcast or total field coverage. If spraying a band over the row area only, then the treated area is only a portion of the whole field and rates must be reduced accordingly. For example, when spraying 1 m bands on rows 3 m apart, only one third of the field is treated.

To avoid calculating areas each time you spray herbicides in bands, record the actual area sprayed in each of your fields. Also record the actual area sprayed by one sprayer tank.

The following information is intended to assist in the selection of varieties. It is gathered from a number of sources including local trials and the experience of local growers. Consider information from other sources when deciding the varieties to plant. Also discuss the varieties with the intended fruit buyer.

Only buy nursery plants that have been grown according to an accepted propagation protocol which includes isolation, aphid management and testing for scorch, shock and other viruses. The following varieties are listed in approximate order of ripening.

Varieties marked with * can be machine harvested.

Varieties for South Coastal B.C.

Earliblue*

Early. Fresh market. Bush: Upright, moderately vigorous, easy to grow. Moderate producer. Avoid poorly drained soil and frost pockets. Potential for machine-harvesting. Fruit: Medium large, light blue, medium scar and on loose clusters. Resistant to cracking. Good flavour and quality. Ships well.

Duke (PDF)*

Early. Processing and fresh market. Bush: Upright stocky and open. Performs poorly in wet or heavy soils. Prune heavily to encourage new growth and maintain fruit size. Blooms late, produces early and consistently. Heavy producer. Harvested in two picks. Fruit: Large-size, light blue, firm and with a small scar. Flavour is maintained in cold storage. Excellent for IQF (individual quick freeze) and fresh shipping.

Reka (PDF)*

Early. Processing. Bush: Upright, very vigorous, heavy production beginning in the first few years after planting, machine harvests well. Grows well on a wide range of soils. Fruit: Medium size, medium blue, firm and with a small scar. Produced on loose clusters. May have “red back” if not fully ripe.

Spartan*

Early. Fresh market. Bush: Upright, open bush with moderate vigour and production. Blooms late and ripens early. Harvest in two main picks. Fruit: Very large, light blue, firm, medium scar. Excellent fresh quality and flavour.

Northland (PDF)*

Early mid-season. Processing market. Bush: Vigorous, medium height, spreading at the base. Requires annual heavy pruning at crown to machine harvest. Consistently very productive. Fruit: Medium size, medium blue, medium firm, small to medium scar. Good sweet flavour with high brix.

1613-A (Hardyblue) (PDF)

Mid-season. Processing market. Bush: Open, upright bush of good vigour. Quick to establish. Consistent good producer. Machine harvests in two picks. Fruit: Medium size, medium firm, light blue, and produced in open clusters. Fruit tends to shrivel on the bush when fully ripened. Very sweet with high brix.

Draper (PDF)*

Mid-season, slightly earlier than Bluecrop. Processing and fresh market. Bush: Vigourous, compact. Young plants may sucker heavily and grow horizontally. Should be well adapted to machine harvesting, ripening is concentrated. Fruit: Large, light blue, small scar, very firm and crisp, excellent flavour, good shelf-life.

Bluecrop (PDF)*

Mid-season. Processing and fresh market. Bush: Vigorous, upright, consistently productive and easy to grow. Plant tends to over-produce unless carefully pruned each year. Harvest in three to four picks. Fruit: Large, light blue, small scar, firm. Good flavour. May be half-red if picked too early.

Chandler (Trial)

Mid-season-late. Fresh market - direct sales Bush: moderate vigour, slightly spreading habit. Prone to bacterial blight. May be difficult to pollinate and set fruit. Fruit: very large, medium firm, medium color, excellent flavour, fruit ripens over a very long season.

Rubel*

Late. Processing. Bush: Upright bush, medium vigour. Fruit: very small, even ripening, well adapted to machine harvesting, excellent flavour. Rubel was one of the first named blueberry varieties selected from the wild.

Liberty (PDF)*

Late, slightly earlier than Elliot. Processing and Fresh Market. Bush: Very vigorous, upright to slightly spreading. Should be trellised. Fruit: medium to large, slightly flat, medium blue, very firm, small scar, excellent flavour.

Elliott (PDF)*

Very late. Fresh market. Bush: upright, vigourous, consistently productive. Fruit: Medium size, light blue, firm, small scar, slightly tart flavour. Fruit tends to shrivel if over mature. Good for CA storage.

Aurora (PDF)

Very late. Fresh market. Bush: vigourous, slightly spreading, likely too late for most Fraser Valley locations. Potential for late season tunnel production. Fruit: medium, dark blue, firm, very small scar, slightly tart.

Cargo (Trial) (PDF)

Last Call (Trial) (PDF)

Top Shelf (Trial) (PDF)

Calypso (Trial) (PDF)

Varieties for Colder Growing Areas

Variety selection for areas with a shorter growing season or colder winter temperatures than south coastal B.C. is especially important. Snow cover can prevent winter injury in particularly cold areas. The following varieties are reputed to have greater cold hardiness in areas with the given annual minimum temperature range.

-30° to -34° C

Bluetta

Early. Bush: Small, low growing and spreading. Produces moderate yields. Mechanical harvest after the first pick. Fruit: Medium sized, blue-black, broad scar. Flavour and firmness is fair.

Patriot

Early. Bush: Small to medium, slow growing and productive. Branches are flexible and bend under heavy snow loads. More tolerant of heavy or wet soils. Blooms early and may be prone to late spring frosts. Fruit: Large, medium-blue, firm, small dry scar. Tends to be half-red if picked too early. Completely ripe fruit has good flavour and sweetness.

Northland

See above. Bush: Branches are flexible and bend under heavy snow loads. Adaptable to different soil types. Fruit: Short ripening period.

Bluejay

Mid-season. Bush: Upright, spreading and vigorous. Consistently productive but needs regular, severe pruning. Fruit: Large, dark blue, good flavour and firm.

Bluecrop

See previous. Plant in protected areas.

-34° to -40°C

Northblue

Mid-season. Bush: Low, vigorous, with low to moderate yields. Fruit: Medium-sized, dark blue, firm and good flavour.

Northland

See above.

-40° to -43°C

Northsky

Bush: Low with dense branches. Fruit: Small to medium, sky blue, and stores well.

Northblue

See above.

Northcountry

Bush: Low with moderate vigour. Fruit: Medium-sized, sweet and mild flavour.

Cover crops in blueberries are usually permanent grass covers between the rows. They suppress weeds, provide support for farm machinery, improve soil structure and water infiltration and reduce soil erosion. Grasses that work best are low-growing perennials that are easy to establish and do not creep. Mixtures should contain no more than 25% perennial ryegrass to minimize mowing. Pure stands of sheep fescue or hard fescue establish slowly but withstand traffic well and require less mowing.

Seed in spring or early fall (September). Seed mixtures at 30 to 55 kg/ha (12 to 22 kg/acre) and fescues at 30 to 45 kg/ha (12 to 18 kg/acre). Irrigate to establish grass covers or time seeding with rainy periods. Mow cover crops regularly during the growing season to control annual weeds. Unmowed cover crops can attract field mice. Control cover crops that creep into the row by applying herbicides in a band along the edge of the cover crop beside the sawdust mulch.

Do not allow dandelions or other early flowering weeds to grow in between rows. When they bloom they can attract bees away from blueberry flowers.

Nutrition

Refer to the Berry Production Guide: Nutrient Management (PDF) for more information.

Soil Analysis

On established plantings, soil analysis is not as useful as tissue analysis. Specific soil test recommendations have not been developed for blueberries. General recommendations based on soil test levels are in the soil management section of this guide. Conduct a soil analysis every 3 or 4 years to monitor changes in pH, P, K, Ca and Mg.

Because fertilizer is applied to the soil within the drip line of the plant, regular monitoring of pH is especially important. Soil pH declines in this area over time. See “New Plantings” above for information on modifying soil pH.

Leaf Analysis

Leaf analysis is the best method to determine nutrient needs in blueberries. Take leaf samples from mid-July to mid-August to determine the fertilizer requirements for the following year. Leaf analysis may also be used earlier in the year or after harvest, if a nutrient deficiency is suspected. For the best interpretation, take leaf samples at the same stage of plant development (e.g. mid-harvest or late-harvest) each year and monitor year-to-year trends in nutrient status.

For routine leaf analysis, collect the most recent fully expanded leaves from the current season’s growth. Select about 5 leaves from 10 plants randomly distributed through the field. If leaf analysis is to be used to diagnose a problem, take separate samples from good and poor growth areas for comparison. Leaves must be free of soil, pesticide and irrigation water residue. Air dry them in an open paper bag or take them directly to a lab.

Table 2. Suggested range of leaf nutrient levels for blueberries based on July leaf analysis
Element Low Adequate High
Nitrogen (N) % < 1.75 1.75 to 2.0 2.0+
Phosphorus (P) % < .08 .08 to 0.1 0.1+
Potassium (K) % < .2 .2 to .40 0.4+
Magnesium (Mg) % < .13 .13 to .25 0.25+
Calcium (Ca) % < .4 .4 to .8 0.8+
Iron (Fe) ppm < .60.0 60 to 200 200+
Boron (B) ppm < 30.0 30 to 80 80.0+
Zinc (Zn) ppm < 8.0 8 to 30 30.0+
Copper (Cu) ppm < 5.0 5 to 15 15.0+
Sulfur (S) % < 0.11 .11 to .16 .16+

Nitrogen (N)

Blueberries require annual soil applications of N to maintain adequate vigour. The rate depends on the plant age, plant spacing, leaf tissue N level, and the observed vigour and productivity of the plants. Avoid using fertilizers containing only nitrate forms of nitrogen (such as calcium nitrate) as they may cause injury or reduced growth. Also monitor soil pH as levels above 5.5 result in more released nitrate from all sources of nitrogen fertilizer.

Unless using a slow release fertilizer, N should be applied in split applications — the first in April when growth begins and the second in early June. Later N applications may encourage late summer growth and increase susceptibility to winter injury and bacterial blight. Slow release fertilizers are applied once, usually in April. Follow the manufacturers’ directions for blends and application rates to avoid late season N release. Young plants require less N than older plants as shown in Table 3.

Table 3. Annual nitrogen requirements for plants of different ages-based on 2470 plants/ha (988 plants/acre)
Field age of plants N (gm/plant) N (kg/ha)
1 6 15
2 8.5 20
3 14 35
4 23 55
5 28 70
6 31 80
7 40 100
8* 45 115

*Plants older than 8 years may require up to 155 kg N/ha

Phosphorus (P)

Apply P at the following rates if soil and leaf P tests are low.

Table 4. Phosphorus application rates based on leaf analysis
Leaf P % Amount of P2O5
kg/ha
< .08 45 to 70
0.08 to 0.10 0 to 45
> 0.10 0

Phosphorus and potassium (K) do not move readily in the soil. In new plantings, broadcast and incorporate P and K in the row before planting. In established plantings, place P and K around the bush near the root zone in early spring before bud break. Irrigate if rain does not occur within 2 days.

Potassium (K)

Potassium deficiencies are relatively rare. Low leaf K can be caused by drought, poor drainage or very low soil pH. Deficiency levels in leaves can also occur with a heavy crop load but normal levels can return after harvest. Excess K can interfere with the uptake of other nutrients. Apply Kif leaf analysis indicates a deficiency.

Table 5. Potassium application rates based on leaf analysis
Leaf K % Amount of K2O
kg/ha
< 0.2 85 to 115
0.2 to 0.4 0 to 85
> 0.4 0

See “Phosphorus” for application methods.

Minor Elements

Magnesium is low in many blueberry soils in B.C. Magnesium oxide (MgO) at 2 to 8% in the basic fertilizer is usually enough to take care of the plant’s needs. Correct deficiencies during the growing season by applying a spray containing 1 kg of magnesium sulfate (Epsom salts) in 100 L of water. Spray to thoroughly wet the bushes and spray under cool, slow drying conditions. If the soil pH drops below 4.5 and calcium is required, then apply dolomite lime at 1 to 2 T/ha.

Calcium deficiencies seldom occur. If detected, correct by applying foliar sprays of commercial Ca materials following the manufacturers’ directions. Use calcium nitrate with care as high levels of nitrate can cause plant injury. If soil pH is above 5.0, apply gypsum at 1 to 2 T/ha. On highly acid soils (pH < 4.0) apply dolomite lime at 1 to 2 T/ha.

Iron (Fe), boron (B), zinc (Zn) and copper (Cu) are other minor elements that can be deficient in blueberries. Iron deficiency symptoms (yellowing of new leaves) often occur when pH is too high (above 5.5). The pH should be lowered by applying sulfur (see Soil Amendments). It may take several years for the sulfur to correct the problem. Short term control of iron deficiency may be obtained with foliar sprays.

Apply nutrient sprays under slow drying conditions to wet the bushes at the rates listed in Table 6. Apply about 500 L/ha (200 L/acre) to mature bushes. Copper is very toxic if applied at an excessive rate. If foliar Cu is low, use a trial application of copper sulphate on a few plants before applying to the entire field. Toxicity can occur at leaf levels over 20 ppm.

Some minor elements can also be applied to the soil to overcome deficiencies. Most complete fertilizer mixes available for blueberries contain B, Zn, Fe, and Cu.

Table 6. Foliar application rates for some minor elements
Element Material Rate
Iron Iron chelate (10% Fe) 50 to 100g/100 L
Boron Solubor, Borospray (20% B) 50g/100 L
Boron Borosol 10 1.2 to 2.4 L/ha
Zinc Zinc chelate (14% Zn) 50 g/100 L
Copper Copper sulphate (25% Cu) 50g/100 L

Fertilizers

Fertilizer rates and blends to use will vary depending on soil type, variety and management practises. Annual leaf analysis is the best method to determine nutrient requirements.

Common blueberry blends for mineral soils include 18-9-9 and 15-10-11. On peat soils, use lower nitrogen blends such as 4-20-17 and 6-31-12. These blends also include secondary and minor nutrients such as sulphur, magnesium, zinc and boron. Other similar blends can also be used. Fertilizer mixes should use sulphated or chelated minor element sources and be free of chloride.

Fertilizer should be applied in split applications unless a slow release nitrogen source is used in the blend. For young plants, common application rates are 20 to 40 g per plant per year of growth to a maximum of about 400 g/plant. Adjust rates each year according to tissue analysis and growth performance.

Fertilizer Placement

On older plants, broadcast the fertilizer in a band evenly over the soil surface under the canopy. Fertilize both sides of the row. Refer to “New Planting” for information on young plants.

Annual pruning is necessary to maintain yields and berry size and quality. It also helps to improve control of diseases and insects. Pruning is best done during the dormant period — from November to late February. This gives the carbohydrates produced in the fall time to move into the crown and roots.

During the first two years of establishment, concentrate on removing weak, low growth and stripping off flower buds to encourage production of vigourous upright whips. In the early years of crop production, prune lightly, removing only the low, weak and horizontal growth.

For mature plants, each year remove several of the oldest, weakest canes to encourage production of strong new shoots from the crown. Remove all weak, twiggy or diseased wood by cutting back to strong side-shoots. Remove low growth which will end up on the ground when loaded with fruit. Prune out crossing branches and excess wood in the centre of the bush to keep it open which allows good air movement and penetration of sprays.

For mechanical harvesting, keep the base of the plant narrow and prune for upright branches and a relatively open center. This allows the catcher plates to stay closed and recover more berries. For more information on pruning see the Oregon State University Extension Service video, VTP 002, “Pruning Highbush Blueberries — A Growers’ Guide”. A Punjabi version is available from the BCAGRI or the BC Blueberry Council.

Rejuvenate overgrown and poor yielding plants by complete top removal during the late dormant stage. Local experience has shown that plants topped 45 to 60 cm (18 to 24 in) above the soil are back in full production within 3 to 4 years.

Insect pollination is essential for good blueberry yields. Most pollination occurs with commercial and wild bees. Wild bumblebees are among the most effective pollinators as they will work early in the morning, late in the evening and under cooler conditions than honey bees. Renting honeybee colonies to provide pollinators is especially important in areas with few wild pollinators.

Refer to the Berry Production Guide: Pollination (PDF) for more information on pollinators, colony rental and management. Blueberry varieties with blossoms that do not attract bees or which are difficult for bees to enter (e.g. Bluejay) require more colonies per hectare to increase pollination opportunities. Table 7 gives an indication of the number of hives required for some varieties. Some growers have found that even higher hive numbers per acre have resulted in increased fruit set and size.

Table 7. Number of hives
Variety per ha (acres)
Rancocas, Rubel 1.2 (0.5)
Weymouth, Bluetta, Bluejay, Pemberton, Duke 2.5 (1)
Bluecrop 3.7 (1.5)
Berkeley, Elliott 5 (2)
Jersey, Earliblue, Bluejay, Brigitta 6 (2.5)

 

Blueberry Weed Management

Before Weed Emergence: Herbicide Application Rates
  Product Rate Comments
Broadleaf seedling weeds Sencor 75 DF (75% metribuzin) 1.0 kg/ha (0.4 kg/acre)
  • Apply as a banded spray to the soil surface directed to the base of non-bearing blueberry bushes in a spray volume of 150 to 300 L water/ha (60 to 120 L/acre).
  • Apply preemergence to the weeds.
  • Do not use on soil with less than 2% organic matter.
  • Rainfall and/or overhead sprinkler irrigation is necessary to move the herbicide into the upper soil surface where weed seeds germinate.
  • Do not apply if heavy rainfall (more than 2.5 cm) is expected shortly after application.
  • Do not apply excessive irrigation (more than 2.5 cm) after application.
  • Triazine-resistant weeds will not be controlled.
  • Do not apply more than once per season.
  • Do not apply within 2 years of harvest.
Seedling broadleaf and grassy weeds Princep Nine-T (90% simazine) 2.5 to 3.75 kg/ha
(1.0 to 1.5 kg/acre)
  • Apply in early spring before weeds and grass emerge to control seedlings.
  • Use lower rate for coarse, sandy soil and higher rate for clay soils and soils high in organic matter content.
  • Apply in a minimum of 300 L/ha (120 L/acre) of water.
  • Do not apply to plantings less than a year old.
Seedling broadleaf and grassy weeds Sinbar 80W
(80% terbacil)
2.75 to 4.25 kg/ha
(1.1 to 1.7 kg/acre)
  • Apply in spring before weeds emerge to crops established at least one year.
  • Use the higher rate on organic and muck soils.
  • Do not apply to sandy soils or soils with less than 1% organic matter or to exposed roots of crop.
  • 5.5 L/ha (2.2 kg/acre) of Gramoxone may be tank-mixed with Sinbar if weeds have emerged.
  • Apply in a minimum of 200 L/ha (80 L/acre) of water.
  • Do not apply within 80 days of harvest.
  • Do not apply to plantings less than a year old.
Seedling broadleaf weeds Devrinol 50DF or Devrinol DF-XT
(50% napropamide)
9 kg/ha
(3.6 kg/acre)
  • Apply in fall through early spring (only once per season). Will not control shepherd's purse or lady's thumb. Not recommended for soils with over 10% organic matter.
  • Apply in enough water to get even distribution over the soil surface.
  • Do not apply to frozen ground.
  • If rainfall does not occur within 7 days for a spring or fall application or 2 days for a summer application, irrigate to wet the soil to a depth of 5-10 cm.
  • Do not apply within 70 days of harvest.
Seedling broadleaf weeds Devrinol 10G
(10% napropamide)
45 kg/ha
(18 kg/acre)
  • Apply in the fall through early spring prior to weed emergence (only once per season).
  • Will not control shepherd’s purse or lady’s thumb.
  • Requires mechanical incorporation, adequate irrigation or natural moisture for optimum results. The treatment must reach the zone of weed seed germination.
  • If rainfall does not occur within 7 days for a spring or fall application or 2 days for a summer application, irrigate to wet the soil to a depth of 5 to 10 cm.
  • Do not apply to frozen ground.
  • Do not apply within 70 days of harvest.
Seedling and perennial broadleaf weeds and grasses Casoron G-4 (4% dichlobenil) 175 to 225 kg/ha
(70 to 90 kg/acre)
  • Apply in the dormant period (late winter) when temperature is below 15o C. Casoron is volatile above this temperature so must be irrigated in immediately or have rains shortly after treatment at higher temperatures.
  • Do not apply the high rate more often than every other year.
Seedling broadleaf weeds Chateau WDG (51.1% flumioxazin) 280 to 420 g/ha (112 to 168 g/acre)
  • Apply in early spring before bud break and emergence of weeds.
  • Use the low rate on coarse textured soils with less than 5% organic matter and the higher rate on medium texture soils with less than 5% organic matter. Do not apply to fine-textured soils or to soils with more than 5% organic matter.
  • Use enough water to ensure good coverage of the soil surface.
  • Apply to well-drained soil as crop injury may occur from applications made to poorly drained soils and/or under cool, wet conditions.
  • At least 0.5 cm of rainfall or irrigation is necessary to activate the herbicide.
  • Do not apply after bud break unless using hooded or shielded application equipment to ensure spray drift will not come in contact with the crop.
  • Do not apply to crops established less than 2 years.
  • Do not apply more than twice in a growing season.
  • Do not make a second application within 30 days of the first spray.
  • Do not apply within 7 days of harvest.
Seedling broadleaf weeds and some grasses Authorithy (480 g/L sulfentrazone) 0.29 L/ha (0.12L/acre)
  • Apply as a broadcast spray or as a uniform band to the base of berry and beds in berries.
  • Apply a single spray in a minimum water volume of 100L/ha (40L/acre.
  • Apply to crops that have been established for one full growing season and are in good health and vigor.
  • Avoid direct or indirect spray contact to foliage and green bark (wrap trunk with nonporous wrap, grow tubes, or wax containers to keep spray solution off of green tissue).
  • At least 0.5 cm of rainfall or irrigation is necessary to activate the herbicide.
  • Do not apply in any type of soils with more than 6% organic matter.
  • Do not apply after petal fall unless a shielded sprayer is used.
  • Do not tank mix with Chateau herbicides (flumioxazin) or with other products containing sulfentrazone.
  • Do not apply within 3 days of harvest
Seedling grasses Dual Magnum or Dual II Magnum
(915 g/L S-metolachlor and R-enantiomer)
1.25 to 1.75 L/ha (0.5 to 0.7 L/acre)
  • Apply as a banded application to the base of plants in early spring before weed emergence.
  • Apply in 150 to 300 L /ha (60 to 120 L/acre) of water.
  • Avoid contact with the blueberry trunk and foliage or injury may occur.
  • Do not apply within 30 days of harvest.
Annual grasses and broadleaf weeds Alion (200 g/l indaziflam) 375 mL/ha (150mL/acre)
  • Apply as a directed spray to the soil
  • Only use in plantings established for at least one year and exhibing normal growth and good vigor
  • Do not apply prior to any soil disturbance
  • Apply a maximun of one application per season
  • Do not apply within 14 days of harvest  
After Weed Emergence: Herbicide Application Rates
  Product Rate Comments

Annual Weeds

(Between the rows only)
Aim EC (240 g/L carfentrazone-ethyl) 37 to 117 mL/ha (15 to 47 mL/acre)
  • Apply between the rows with a hooded sprayer to emerged weeds. Crop injury will occur if drift is allowed to come in contact with green stem tissue, leaves, blooms or fruit.
  • To improve control, apply with surfactants such as Agral 90 or Ag-Surf at 0.25% (0.25 L/100 L of water) or Merge at 1% (1 L/100 L of water).
  • Do not apply within 1 day of harvest.
Hard to control perennial weeds Casoron G-4
(4% dichlobenil)
225 kg/ha
(90 kg/acre) or 22.5 g/m2
  • High rate will suppress quackgrass, thistles, horsetail, bracken fern, etc.
  • Do not apply at this rate more often than every other year.
  • Apply in the dormant period (late winter) when temperature is below 15o C. Casoron is volatile above this temperature so must be irrigated in immediately or have rains shortly after treatment at higher temperatures.

Clover (red and white)



Vetch
Lontrel 360
(360 g/L clopyralid)

830 mL/ha
(340 mL/acre)



420 mL/ha
(170 mL/acre)
  • Apply when the weeds are actively growing but not within 45 days of harvest.
  • Avoid contact with crop foliage to prevent injury.
  • Apply in 100 to 200 L/ha (40 to 80 L/acre) of water.
  • Use the higher volume when weed density is high.
  • Apply no more than once per year.
Annual and perennial broadleaf weeds including red root pigweed, lamb's-quarters, creeping yellow cress Sandea (72.6 % halosulfuron

1-4 year old bushes:

35 to 47 g/ha  (14 to 19 g/acre)

Bushes older than 4 years: 

35 to 70 g/ha (14 to 28 g/acre)

  • Apply as a broadcast application to the ground on either side of the row in a minumum of 140 L/ha (56 L/acre) of water.
  • If small weeds are present, tank-mix with a post-emergence herbicide to enhance the spectrum of broadleaf and grass control.
  • Contact with blueberry bushes should be avoided or temporary chlorosis of leaves will result.
  • Do not apply to plants established less than one year or to plants under stress.
  • Do not apply to Elliot plants established less than 4 years.
  • Do not apply to areas where water is known to pond for periods of time following rainfall.
  • Minimum of 45 days between applications.
  • Do not apply more than 140 g/ha (56 g/acre) per 12 month period.
  • Do not apply within 14 days of harvest.
Red root pigweed, barnyard grass and some other broadleaf and grassy weeds, quackgrass suppression Prism SG (25 % rimsulfuron) 60 g/ha          (24 g/acre)
  • Use on crops that have gone through at least one growing season and are in good health and vigour.
  • Apply to actively growing weeds.
  • Use a directed spray application to provide complete coverage of weeds while minimizing spray contact with blueberry plants.
  • Use a non-ionic surfactant such as Cittowett Plus, Agral 90 or Ag-Surf at 2 L/1000 L of spray mixture.
  • When applied as a banded treatment, Prism may be applied twice per year.
  • Do not apply within 21 days of harvest.
Red root pigweed, lamb's quarters, wild mustard and some other broadleaf weeds Callisto 480 SC (480 g/L mesotrione) 300 mL/ha (120 mL/acre)
  • Apply in early spring before emergence of weeds or post-emergence up to the 8-leaf stage of weeds.
  • For post-emergence applications, add Agral 90 at 0.2 % (0.2 L/100 L of water).
  • Do not apply more than once per year.
  • Do not apply after bloom.
  • Do not apply within 60 days of harvest.
Broadleaf seedlings Goal 2XL (240 g/L oxyfluorfen) 1.0 L/ha (0.4 L/acre)
  • Apply as a directed spray when weeds are in the 2-4 leaf stage and actively growing.
  • Apply only once per year.
  • Do not apply within 50 days of harvest.
Grasses, broadleaf seedlings and perennials and woody weeds Velpar L (240 g/L hexazinone)


Velpar DF (750 g/kg hexazinone)
4 to 8 L/ha (1.6 to 3.2 L/acre)


1.28 to 2.56 kg/ha (0.5 to 1.0 kg/acre)
  • Apply before the weeds are 30 cm tall and prior to blueberry bloom.
  • Use lower rate on sandy soils or soils low in organic matter. Most effective under conditions of high temperature (above 27o C), high humidity and good soil moisture.
  • Apply in 100-300 L/ha (40 - 120 L/acre) of water.
  • Controls tough weeds such as trailing blackberry, hardhack, oxeye, daisy and goldenrod.
  • Do not re-enter treated areas within 48 hours of application.
  • Registered for use on Bluecrop variety only. Do not apply within 60 days of harvest.
Grassy and broadleaf weeds Ignite SN (150 g/L glufosinate ammonium)

2.7 to 5.0 L/ha

(1.1 to 2.0 L/acre)
  • Apply as a directed spray around the base of blueberry bushes in 330 to 1100 L/ha (130 to 440 L/acre) of water.
  • Do not allow spray to drift onto leaves or green bark as crop damage will occur.
  • A repeat treatment may be necessary to control new germination of annual weeds.
  • Do not make more than 2 applications per year.
  • Do not apply more than 6.7 L/ha (2.7 L/acre) total product in one season.
  • Do not apply within 14 days of harvest.
Quackgrass, perennial, and annual weeds Roundup
(356 g/L glyphosate)
2.8 to 5.6 L/ha
(1.1 to 2.3 L/acre)
  • Use as a directed or shielded spray using no more than 275 kPa pressure. Apply in 50 to 300 L/ha (20 - 120 L/acre) of water. Addition of a surfactant is required for water volumes above 150 L/ha (60 L/acre).
  • Do not let spray contact fruit, foliage, canes or exposed roots.
  • Apply only once per season and not within 30 days of harvest.
  • The listed rates are based on a formulation with 356 g/L glyphosate. There are many new formulations of glyphosate on the market with varying active ingredient concentrations. Be sure to check the label for application rates.
Quackgrass and annual grasses Centurion or Select (240 g/L clethodim)

190 to 380 mL/ha

(75 to 150 mL/acre)
  • Apply as a directed post emergence spray in at least 100 L/ha (40 L/acre) of water.
  • Use the low rate for annual grasses and the high rate for quackgrass.
  • Use in combination with 0.5-1.0% Amigo adjuvant.
  • Weeds should be in the 2 to 6 leaf stage.
  • Do not apply more than once per year.
  • Do not apply within 14 days of harvest.
Quackgrass and annual grasses Venture L
(125 g/L fluazifop- p-butyl)
2.0 L/ha
(0.8 L/acre)
  • Apply prebloom in the spring to actively growing quackgrass at the 3 to 5 leaf stage. A rate of 1.2 L/ha (0.49 L/acre) will control annual grasses (2 to 6 leaf stage).
  • Apply only once per season.
  • Apply in 100 to 300 L/ha (40 to 120 L/acre) of water. Use the higher volume when weed density is high.
  • Do not apply within 15 days of harvest.
  • Warning: women capable of bearing children should avoid exposure to Venture.
Quackgrass and annual grasses Poast Ultra
(450 g/L sethoxydim)
1.1 L/ha
(450 mL/acre)
  • Apply to actively growing quackgrass up to the 3 leaf stage (8 to 12 cm high). Merge should be added to all applications at a rate of 1% of water volume.
  • Apply in 50 to 200 L/ha (20 to 80 L/acre) of water.
  • Use the higher volume when weed density is high.
  • Maximum 2 applications per season
  • Allow a minimum of  14 days between applications
  • Do not apply within 1 day of harvest.
Yellow nutsedge Basagran (480 g/L bentazon) 1.75 L/ha
(0.7 L/acre)
  • Apply as a directed spray when nutsedge is 15 to 20 cm tall. Repeat application in 7-10 days, but do not apply more than twice per year.
  • Apply with 2.0 L/ha (0.8 L/acre) of Assist Oil Concentrate in 100 to 400 L/ha (40 to 160 L/acre) of water.
  • Do not apply within 25 days of harvest.
Broadleaf weeds Ipco 2,4-D 600 (560 g/L dimethylamine salt) 1.7 L/ha (0.7 L/acre)
  • Apply as a directed spray only (between the rows)  in early spring after weeds have emerged and are actively growing. Do not overspray.
  • Do not apply more than once per season.
  • Do not apply within 30 days of harvest.
Annual Grasses and Broadleaf Weeds AXXE (36% Ammonium Salt of Fatty Acid  45 to 106 L/ha (18 to 42 L/ac) 
  • Bioherbicide for burndown of weeds
  • Adjust rate and water volume depending on height of weeds as specified on label
  • Use as a shielded spray application and do not allow spray to contact the crop
  • Do not apply within 2 hours of rainfall or irrigation
  • Can also be applied prior to weed emergence

 

Blueberry Insect & Mite Management

Most insecticides are toxic to bees. Do not apply them during the blossoming period.

Note: The recommended spray rates are for mature bushes unless otherwise specified. For smaller, immature bushes use reduced amounts of spray mixture.

 

Hosts

All blueberry varieties are susceptible to aphid attack.

Damage

Most aphids are found on new shoot growth where they feed by sucking sap. Aphid numbers are seldom high enough to weaken or stunt growth by removing sap. Occasionally high aphid levels occur, slowing growth, reducing yields, and making berries sticky with honeydew and sooty mould.

Aphids spread blueberry scorch virus which, in infected plants, is at highest levels during the spring. Greater aphid numbers mean increased potential for virus spread by wingless aphids that walk between plants within a row and by winged aphids that fly between rows. Recent research suggest that most of the virus transmission occurs in June and early July when populations of resident aphids on blueberry are at peak density and large flights of migrant aphids occur.

Aphid

Identification

Almost all (over 98%) aphids on blueberries are Ericaphis fimbriata. This is a small to medium-sized aphid (adults 1-2 mm), with yellowish green or red nymphs, green or red wingless adults and black winged adults. They are found singly or in colonies, on opening flower or leaf buds in March, and on the under-surface of new leaves in the spring, and new and old leaves in the summer.

Life History

Aphids over-winter as black eggs (0.5 mm long) on stems near buds, and in the leaf litter. In the Fraser Valley the eggs hatch from late February to the end of March, when the buds start to open. Young wingless aphids (nymphs) will feed on unopened buds, then on blossoms and growing shoots. Asexual reproduction (daughter-to-daughter) for several generations results in rapid population increase. Winged adults are produced all season starting in early May.

Populations peak from mid-June to mid-July and subsequently decline naturally through a reduction in plant quality which affects aphid birth and development rates, and through biological controls. Sexual aphids are produced in September. These mate and produce eggs in October.

Monitoring

Over wintering aphids are very difficult to detect in the spring as they are within buds and developing blossom clusters. To effectively control the spread of virus, a pre-bloom spray is recommended to prevent populations from building later in the season. See Chemical Control below.

Monitoring should begin during the latter part of bloom to determine if post-bloom sprays are required. Check the top 30 cm of growth on 10 branches per plant. Consider treatment if 30% or more of the tips have aphids.

Management

Cultural Control

Excessive growth caused by too much N favours a build up of aphids.

Biological Control

A number of native beneficial insects feed on and parasitize aphids. These include ladybird beetles, syrphid larvae, lace wing larvae, and small parasitic wasps. The decline in aphid populations during July and August is caused partly by beneficial insects. Most insecticides will damage native beneficials so they should be used only when necessary.

Chemical Control

If blueberry scorch virus is present, or if it exists within the area, chemical aphid control is recommended in April, pre-bloom, to reduce the rate of spread. If all growers effectively control the over wintering generation it will help prevent aphid populations from building later in the season.

This spray is timed after all aphid eggs have hatched, and before winged forms are produced. Additional sprays after bloom may be required if few beneficial insects are present and aphid populations are increasing. The following products are recommended:

Chemical Control of Aphids
Product Active Ingredient Rate  PHI* Comments

Admire 240F

or

Alias 240SC

240 g/L imidacloprid

175 mL/ha

(70 mL/ac)

3

 

 

14

  • Group 4A
  • Apply post bloom after bees have been removed from the field
  • Use enough water to obtain good coverage (up to 1000 L/ha).
  • Allow at least 7-10 days between applications.
  • Maximum 2 applications per season
Assail 70WP 70% acetamiprid

56 to 86 g/ha (22 to 34 g/ac)

7
  • Group 4A
  • Apply post bloom after bees have been removed from the field
  • Use in a minimum of 187 L/ha (75 L/acre) of water by ground application
  • Do not apply during bloom as Assail is toxic to bees directly exposed to treatment. 
  • Maximum 4 applications per season
Concept Liquid 75 g/L imidacloprid, 10 g/L deltamethrin

560 mL/ha (224 mL/ac)

14
  • Group 3 + 4A
  • Apply post bloom after bees have been removed from the field  
  • Concept will also control caterpillars.
  • Use enough water to obtain good coverage.
  • Allow at least 5 days between applications.
  • Maximum 3 applications per season
  • Concept is not acceptable to all markets. 
Exirel 100 g/L cyantraniliprole

750-1500 mL/ha (300-600 mL/ac)

3
  • Group 28
  • Apply pre or post bloom.
  • Do not apply during bloom as Exirel is toxic to bees.
  • Use enough water to obtain good coverage.  
Fulfill 50WG 50% pymetrozine

193 g/ha (77 g/ac)

85
  • Group 9B
  • Apply pre bloom.
  • Use in enough water to obtain good coverage (500 to 1000 L/ha).
  • A second application may be made post-harvest if aphid numbers warrant.
  • Maximum 2 applications per season.
Movento 240 SC 240 g/L spirotetramat

220 to 365 mL/ha (88 to 146 mL/ac)

7
  • Group 23
  • Apply post bloom after bees have been removed from the field
  • Use enough water to obtain good coverage.
  • Do not apply more than a total of 0.72 L/acre per season.
PyGanic EC1.4 1.4% pyrethrins

2.32 to 4.65 L/ha (0.93 to 1.86 L/ac)

0
  • Group 3
  • Apply pre or post bloom.
  • Use enough water to ensure complete coverage of all plant surfaces.
  • Apply promptly after mixing.
  • Do not reapply within 7 days
  • OMRI approved for organic production. Maximum 8 applications per season.
Sivanto Prime 200 g/L flupyradifurone

500-750 mL/ha (196-295 mL/ac)

3
  • Apply pre or post bloom.
  • Use in a minimum of 100 L/ha (40 L/acre) of water as a directed foliar spray.
  • Do not apply more than once every 7 days.
  • Do not exceed 787 ml/acre per season.

*PHI = Pre-harvest interval (days)

Hosts

Blueberries, cranberries.

Damage

Larvae feed in the growing tips of the plant causing excessive branching of new growth. This is particularly a problem in young plantings as bushes may be slower to reach adequate height for machine harvesting. Midge damage and resulting branching may be less important in older plantings.

Identification

The adult is a very small midge-like fly. The tiny larvae (maggots) are clear (first instar) or greenish-white (second instar) or orange (third instar), with no visible head. The third and last instar maggot is about 2 mm long. Pupae are enclosed in a silken cocoon in the damaged tip.

Life History

This insect over-winters as a pupa in the soil, and in mid-April the adult fly emerges and begins laying eggs in the growing tips of the plants. Each female lays 35 to 40 eggs. The life cycle from egg to adult takes 22 to 25 days, so there are several generations a year. Generations may overlap and all stages may be present together on one plant.

Monitoring

Examine growing tips for signs of distortion and discoloration. Inspect growing tips with a hand lens and tease apart to see maggots.

Management

Chemical Control 

Chemical Control of Blueberry Midges
Product Active Ingredient Rate PHI* Comments
Exirel 100 g/L cyantraniliprole

750 to 1000 mL/ha (300 to 400 mL/acre)

3
  • Use enough water to obtain good coverage
  • Do not apply during bloom as Exirel is toxic to bees.
  • Do not apply more than 4 times per season or a maximum of 4.5 L/ha (1.8 L/acre).
  • Tank mixes and sequential applications with strobilurin (Pristine, Cabrio), copper and captan fungicides are not recommended as crop injury has resulted under lab settings.
Movento 240 SC 240 g/L spirotetramat

365 to 435 mL/ha (146 to 174 mL/acre)

7
  • Use enough water to obtain good coverage
  • Apply post bloom after bees have been removed from the field when hatching midge eggs are detected.
  • Use the higher rate when pest pressure is heavy, canopy is heavy or insect development is extended (cool weather).
  • Do not apply more than a total of 1.8 L/ha (0.72 L/acre) per season.
  • Allow at least 7 days between applications

*PHI = Pre-harvest interval

Hosts

Berries, fruit trees, ornamental and native deciduous trees.

Damage

Spanworms and winter moth are primarily early season pests. They can cause severe crop loss in early spring by boring into swelling buds and feeding on petals and flower parts. They also chew on new leaf growth. Severe infestations, if not controlled, can result in complete loss of fruit production and total defoliation.

Leafrollers can cause similar damage, but usually occur later in the season. They feed on blossom and fruit clusters from late April through early June. The second generation larvae feed on leaves and berries and may become a contaminant in harvested fruit.

Identification

Bruce’s Spanworms and Winter Moth

Larva

Light or dark green with pale lines along the body. About 1 cm at full length. Often arch their body when moving along a branch.

Adult

Wingless female rarely seen; male moth with thin wings banded with brown and grey.

Oblique banded leafrollers

Oblique Banded Leafrollers

Eggs

Greenish masses of up to 150 eggs on leaves.

Larva

Caterpillars are light cream to dark green with brown to black heads and up to 12 mm long.

Adult

Moths are buff-coloured or grey with wing spans up to 2 cm. Various other caterpillar species can also feed on blueberries. Contact BCAGRI or your crop consultant to identify and assess damage.

Life History

Bruce’s Spanworm and Winter Moth

Wingless females deposit eggs singly on trunks and stems of host plants in November and December. Tiny caterpillars (about 1 mm long) emerge in late March to early April. Larvae can be found on plants until early June when they drop to the ground. Larvae pupate in the soil and remain there until they appear as adults in November to December, to mate. There is one generation each year. Adults and larvae of both species look very similar and are usually present together.

Oblique Banded Leafrollers

The insect overwinters as eggs under loose bark or as small larvae. In April, larvae begin to feed on developing shoots and blossom clusters and roll up leaves. Feeding continues until late May to early June followed by pupation and moth emergence in late June to early July. Eggs are laid and a second generation of larvae feeds in July and August. The oblique-banded leafroller has two generations each year while other leafroller species may have one to three generations.

Monitoring

Examine buds, shoots and blossom clusters for larvae and feeding damage weekly beginning in late March. Spanworms spin silken threads. Leafrollers roll up leaves. Watch for feeding damage on new growth and within blossom clusters. Successful control depends on treatment shortly after egg hatch, before larvae bore into buds or get within blossom clusters. Treatments should be applied if more than 5% of the terminals and floral parts have larvae and/or damage.

Management

Cultural Control

Pruning and good weed control helps to reduce numbers by removing over wintering sites.

Biological Control

Native parasitic and predatory insects, as well as spiders can help to reduce caterpillar populations.

Bacillus thuringiensis, kurstaki (Foray 48BA, Dipel) is a bacterium that acts as a stomach poison against caterpillars. It is not toxic to bees or to other beneficial insects. See below for recommendations on its use.

Chemical Control

A spring pre-bloom treatment is generally required if larvae and/or damage are found in more than 5% of terminals. An additional treatment may be required between the end of bloom and harvest to control second generation leafrollers that may damage or contaminate fruit.

Do not spray with products other than Bt during the blossom period to avoid killing bees.

Use one of the following:

Chemical Control of Caterpillars (Leafrollers, Spanworms, Winter Moth)
Product Active Ingredient Rate PHI* Comments
Altacor 35% chlorantraniliprole 215 to 285 g/ha (86 to 114 g/acre) 1
  • Group 28
  • Use enough water to ensure good coverage.
  • Do not apply during bloom when bees are actively foraging.
  • Use the high rate when insect pressure is heavy.  
  • Do not apply more than 3 times per season.
  • Do not apply more than once every 7 days. 
Confirm 240 F  240 g/L tebufenozide

1.0 L/ha (0.4 L/acre)

14
  • Group 18
  • Apply when young larvae or feeding damage is first detected.
  • Additional applications at 10-14 days intervals may be required if pest pressure is heavy.  
  • Do not apply more than 4.6 L/ha (1.8 L/acre) of product per season. 
Decis 5.0 EC or Decis Flowable 50 g/L deltamethrin

125 mL/ha (50 mL/acre)

14
  • Group 3
  • Use in 1200 to 1500 L/ha (480 to 600 L/acre) of water. More concentrated application rates may cause crop injury.
  • Very toxic to fish.
  • Do not apply near ditches and water courses.
  • Decis is toxic to bees. Do not apply during bloom when bees are actively foraging.
  • Decis is not acceptable for some markets. Check with your packer before using.
Delegate WG 25% spinetoram 100 to 200 g/ha (40 to 80 g/acre) 3
  • Group 5
  • Delegate is toxic to bees. Do not apply during bloom when bees are actively foraging.
  • Apply at egg hatch or to small larvae.
  • Use the higher rate for high populations and/or larger larvae. Repeat if necessary.
  • Do not apply more than 3 times per year.
  • Allow a re-treatment interval of at least 6 days. 

Entrust 80W 

80% spinosad

80 to 109 g/ha (32 to 44 g/acre)

3
  • Group 5
  • Use in 300 to 500 L/ha of water.
  • Do not apply during bloom when bees are actively foraging. 
  • Use the upper rate under high insect pressure and/or on large larvae.
  • Apply a maximum of 3 times per year. 
  • Entrust is OMRI approved for organic production
Exirel 100 g/L cyantraniliprole

500 to 1000 mL/ha (200 to 400 mL/acre)

3
  • Group 28
  • Use enough water to obtain good coverage.
  • Do not apply during bloom as Exirel is toxic to bees.
  • Use the high rate when pest pressure is heavy.
  • Do not apply more than 4 times per season or a maximum of 4.5 L/ha (1.8 L/acre).
  • Tank mixes and sequential applications with strobilurin (Pristine, Cabrio), copper and captan fungicides are not recommended as crop injury has resulted under lab settings

Foray 48BA

 

 

 

Dipel 2X DF

 

 

Bioprotec 3P

Bacillus thuringiensis (Bt)

4.0 L/ha in 600 L water/ha (1.6 L/acre in 240 L/acre water)

 

0.525 to 1.125 kg/ha  (210 to 450 g/acre)

 

0.72 to 1.45 kg/ha (0.29 to 0.58 kg/acre)

0
  • Group 11
  • Apply when caterpillars are young. 
  • Use the higher rates when leafroller numbers are high or for mature leafrollers.
  • Apply in late afternoon or evening as Bt is sensitive to sunlight
  • Bt products not toxic to bees or to other beneficial insects.
  • Bt products are OMRI approved for organic production.
Harvanta 50 g/L cyclaniliprole 1200 to 1600 mL/ha (480-640 mL/acre) 1
  • Group 28
  • Provides suppression only
  • Do not apply more than 2 times consecutively or more than 2 times within a single generation of the target pest
  • Use a spray volume of 935-1400 L/ha (374-560 L/ac) of water
  • Do not apply more than 3 times per year or a maximum of 4.8 L/ha (1.92 L/acre)

Imidan 50WP

or

Imidan 70WP

50% phosmet

 

70% phosmet

2.25 kg/1000 L of water/ha (0.9 kg in 400 L/acre)

1.6 kg/1000 L of water/ha (0.64 kg in 400 L/acre)

15
  • Group 1B
  • Do not apply during bloom when bees are actively foraging. 
  • Do not apply more than twice per year
Intrepid 240 g/L methoxyfenozide

0.5 L/ha

(200 mL/acre)

7
  • Group 18
  • Apply when feeding damage is first detected.
  • Repeat applications after 7-14 days if required.
Sevin XLR  42.8 % carbaryl

4 L/ha (1.6 L/acre)

2
  • Group 1A
  • Use 1200 to 1500 L/ha of water (500 - 600 L/acre). 
  • Do not apply during bloom when bees are actively foraging. 
Success 480SC 480 g/L spinosad

145 to 182 mL/ha (58 to 73 mL/acre)

3
  • Group 5
  • Use in 300 to 500 L/ha of water.
  • Do not apply during bloom when bees are actively foraging. 
  • Use the upper rate under high insect pressure and/or on large larvae. 
  • Apply a maximum of 3 times per year

*PHI = Pre-harvest interval (days)

Hosts

Blueberry, cherry, other stone fruit, apple, hawthorn, rose

Damage

Larvae feed in developing fruit leaving tunnels and frass rendering it unmarketable.

Identification

Egg

Very small, flat, oval eggs laid singly on calyx of green fruit.

Larva

White to pale pink with brown head, 7.5 to 9 mm long

Adult

Small moth (9-11 mm wing span) with dark grey and black wavy stripes (not distinct)

Life History

There is one generation per year. Moths emerge in spring and lay eggs on green fruit. Larvae hatch and burrow into developing fruit. Each larva will infest 1-2 fruit before exiting and searching for an overwintering site in early to mid-August. Larvae overwinter in silken structures in pruning stubs, wounds or under bark and pupate the following spring.

Monitoring

Currently, cherry fruitworm has only been detected in a few B.C. blueberry fields.

Search for eggs on green fruit from late May to mid June. Monitor for adults with pheromone traps from May to August. Research is underway in B.C. to further refine monitoring techniques.

Management

Cultural Control

None

Chemical Control

Insecticide sprays should be applied when eggs and small larvae are present, but before they have entered fruit. Based on B.C. information, this will be post bloom, during green fruit development. A second application should be made 10 - 14 days later. Research is underway in B.C. to better refine spray timing. 

Use one of the following:

Chemical Control of Cherry Fruitworms
Product Active Ingredient Rate PHI* Comments

Altacor 

35% chlorantraniliprole

215 to 285 g/ha (86 to 114 g/acre)

1
  • Group 28
  • Use enough water to ensure good coverage.
  • Use the high rate when insect pressure is heavy.
  • Do not apply more than 3 times per season.
  • Do not apply more than once every 7 days. 

Assail 70WP

70% acetamiprid

160 g/ha (64 g/acre)

7
  • Group 4A
  • Use a minimum of 190 L/ha (75 L/acre) of water by ground application.
  • Do not apply during bloom as Assail is toxic to bees directly exposed to treatment.
  • Do not apply more than 4 times per season.
  • Do not apply more than once every 12 days.

Confirm 240 F 

40 g/L tebufenozide

1.2  L/ha (0.5 L/acre)

14
  • Group 18
  • Apply when egg laying begins.
  • Additional applications at 10-14 days intervals may be required if pest pressure is heavy.  
  • Do not apply more than 4.6 L/ha (1.8 L/acre) of product per season.

Foray 48BA

 

 

 

 

Dipel 2X DF

Bacillus thuringiensis (Bt)

4.0 L/ha in 600 L water/ha (1.6 L/acre in 240 L/acre water)

 

 

0.525 to 1.125 kg/ha (210 to 450 g/acre)

0
  • Group 11
  • Apply when caterpillars are young. 
  • Use the higher rates when leafroller numbers are high or for mature leafrollers.
  • Apply in late afternoon or evening as Bt is sensitive to sunlight
  • Bt products not toxic to bees or to other beneficial insects.
  • Bt products are OMRI approved for organic production
Rimon 10EC 10% novaluron 1.35 to 2.0 L/ha (0.5 to 0.8 L/acre) 8
  • Group 15
  • Use enough water to ensure good coverage.
  • Avoid applying during bloom when bees are present.
  • Use the higher rates and spray volumes when larvae are large or canopy is heavy.
  • Do not apply more than 3 times per season.

Malathion 85E

Malathion 25W

85% malathion

 

 

25% malathion

550 mL/ha (220 mL/acre)

 

2.25 kg/ha (0.9 kg/acre)
 
  • Group 1B
  • Spray bushes for thorough coverage. 

*PHI = Pre-harvest interval (days)

Delegate, Entrust, Success and Decis used for other pests will also help to control cherry fruitworm if they are applied before larvae enter fruit.

Damage

Rarely cause significant crop damage.

Buds

Chewed buds and flower parts by larvae (slugs).

Leaves

Larvae feed on the underside of the older leaves, often leaving the upper layer and veins intact. Appears as brown patches on leaves.

leaf

Identification

Larva

Shiny, green, up to 5 mm long and resemble slugs.

Adult

Dark coloured wasps which may have some bright markings.

Monitoring

Watch for larvae when looking for leafrollers. Usually appear early in the season, maturing and disappearing by mid-bloom. A second generation occurs in late summer.

Management

Cultural Control

Clean cultivation reduces numbers.

Chemical Control

Caterpillar and aphid sprays will also control sawfly larvae. If damage is noticed close to the end of harvest or after harvest, no control is necessary.

Hosts

Ornamental plants and fruit trees.

Damage

Scales suck the sap from the plants reducing plant vigour and terminal growth. Scales secrete honeydew which promotes the growth of a black sooty mould, makes picking unpleasant and may make fruit unsuitable for fresh market.

Identification

Oval, brown bumps up to 5 mm in diameter found on the previous seasons’ growth. Overwintering forms are found on new wood as 2 mm elongate, flat pale spots from September until early spring.

Life History

Overwintering forms complete development by late spring or early summer. White eggs are found under these scales in May or June. The eggs begin to hatch in late June to early July and the young scales (“crawlers”) migrate from under the females in July. They move to the underside of leaves and feed for 4 to 6 weeks before returning to the stems and twigs to overwinter. The scales mate in early spring and the females continue to feed until early fall. The males die after mating.

Monitoring

During the dormant season inspect plants and mark areas where many scales are seen. Start to check for egg hatch and crawler migration in May.

Management

Cultural Control

Prune out and destroy heavily infested branches.

Chemical Control

Apply controls during the following times:

Dormant Season

To control overwintering scale. Generally this control is the most effective and easiest to apply. Apply during the late winter while the plants are fully dormant, usually during January until mid-February:

Dormant spray oil at 20 L/1000 L of water; or

Apply 12.5 L of Dormant Spray Oil  plus 36.7 L of lime sulfur in 1000 L of water. Dormant oil kills scales by suffocation, therefore spray to the point of run-off to obtain good coverage. Apply spray when the temperature is above freezing.

Growing Season

To control the young scale “crawlers.” If honeydew production is severe, apply during the growing season when the crawlers are active, usually late July through August. Use high pressure to ensure good coverage of the undersides of the leaves and the twigs.

Do not spray during the blossoming period to avoid killing bees. Bees sometimes forage on honeydew so apply sprays after bees return to the hives, if possible.

Use one of the following:

Chemical Control of Scale Insects
Product Active Ingredient Rate PHI* Comments
Movento 240 SC 240 g/L spirotetramat 220 to 365 mL/ha (88 to 146 mL/acre) 7
  • Group 23
  • Use enough water to obtain good coverage
  • Apply post bloom after bees have been removed from the field
  • Use the higher rate when pest pressure is heavy, canopy is heavy or insect development is extended (cool weather).
  • Do not apply more than a total of 1.8 L/ha (0.72 L/acre) per season.
  • Allow at least 7 days between applications
Sevin XLR Plus 42.8 % carbaryl

4 L/ha (1.6 L/acre)

2
  • Group 1A
  • Use 1200 to 1500 L/ha of water (500 - 600 L/acre). 
  • Do not apply during bloom when bees are actively foraging. 
Sevin 50W 50% cabaryl 3.25 kg/500 L  1
  • Group 1A
  • Use 1400 to 1700 L/ha (560 to 680 L/acre) of water
  • Do not apply during bloom when bees are actively foraging. 

*PHI = Pre-harvest interval (days)

Hosts

Berries, stone fruits and numerous wild hosts

Damage

Female flies lay eggs under the skin of ripe fruit. Larvae hatch and begin to feed within the fruit, causing softening in the area of feeding. There can be several larvae in a fruit, which hastens softening and fruit collapse. Holes the size of pin pricks are evident within the soft areas of infested blueberries.

Identification

Eggs

0.6 mm long, oval, white, 2 filaments at one end.

Larvae

Legless, headless, up to 6 mm long at maturity, milky-white.

Pupa

3 mm long, brown, football-shaped, two stalks with small finger-like projections on ends.

Adults

2-3 mm (1/8 inch) long, brownish with red eyes and clear fly-like wings. Males have a black/grey spot on the end of each wing, as well as two black ‘combs’ or bands on each front leg.

The females do not have spots or leg bands. Females have saw-like egg-laying organs (ovipositors) that are used to cut into fruit skin. Ovipositors are easier to see when extended. A hand-lens or dissecting microscope is needed to identify ovipositor.

Life History

Spotted Wing Drosophila overwinter as adult flies. In spring flies become active and lay eggs in ripening fruit. Based on climate model predictions, there could be up to 5 generations per year in B.C. Generations overlap as flies are relatively long-lived particularly at temperatures of 20°C and cooler.

Based on Japanese literature, a female can lay eggs for 10-59 days, with 7-16 eggs laid per day, and average 384 eggs per female. Eggs hatch in 2-72 hours, larvae mature in 3-13 days, and pupae reside in fruit or outside of fruit for 3-15 days. In the lab at constant temperature, one generation takes 50 days at 12°C, 21-25 days at 15°C, 19 days at 18°C, 8.5 days at 25°C, and 7 days at 28°C. Adults are attracted to and feed on ripe and decaying fruit.

Monitoring

Flies can be monitored with cup-like traps baited with apple cider vinegar. Place traps when the temperature is consistently over 10°C and/or before fruit starts to ripen. Hang traps in the plant canopy in a shady location. Check traps once per week and look for the Spotted Wing Drosophila adults in the bait solution. Use a hand lens or other magnifier to see the female ovipositor. Replace the bait solution each week. Suspect fruit can also be collected and inspected for larvae.

Management

Cultural Control

Where practical, remove or bury cull fruit to eliminate additional feeding and breeding sites. Keep equipment and processing areas free of old fruit. Think beyond the borders of your farm and be aware of host plants in adjacent fields. Encourage neighbours to also manage for SWD. Shorten picking interval where possible: pick early, clean and often.

Biological Control

To date, there are no commercially available biological controls for Spotted Wing Drosophila. Research is underway to identify potential predators and/or parasites that may be useful in managing Spotted Wing Drosophila.

Chemical Control

Chemical control will be required if trapping shows that adult Spotted Wing Drosophila flies are present in the field when berries begin to ripen. Adults are the target and are killed by direct spray contact and/or when they are exposed to residues of insecticide on the treated fruit and leaves.

Consider the following when planning a spray program:

  • All of the recommended products are toxic to bees. Avoid application when crops are blooming and bees are in the field. If sprays are necessary during this time, they should be applied at night.
  • Use enough water and pressure to ensure adequate coverage. Flies prefer to feed in the lower, shaded part of the canopy.
  • Use spray equipment that will allow effective coverage. Consider crop training and use of trellis wires to improve sprayer access to crop. Currently, no products are registered for aerial application.
  • To limit development of resistance, rotate between the recommended products.
  • A 7 – 10 day spray interval may be necessary to protect fruit through the ripening period depending on temperature and pest pressure.
  • A post-harvest spray may be necessary to prevent flies from building up on residual fruit and spreading to adjacent later ripening crops.

The following products are registered for controlling Spotted Wing Drosophila.  Use one of the following:

Chemical Control of Spotted Wing Drosophila
Product Active ingredient Rate PHI* Comments

Capture 240EC

240 g/L bifenthrin 300 to 450 mL/ha (120 to 180 mL/acre) 3
  • Group 3
  • Use enough water to obtain good coverage of foliage.
  • Use the higher rate when canopy is heavy and/or pest pressure is severe. 
  • Do not apply more than 2 times per season.  
  • Minimum re-treatment interval is 7 days.
  • Last day of sale by retailers is December 31, 2019
  • Last day of permitted use by growers is December 31, 2020

Cygon 480 or Lagon 480

480g/L dimethoate 830 ml in up to 1000L/ha of water. Post harvest only
  • Group 1B
  • Apply post harvest only
  • Use a maximum of 2 applications per year
  • Minimum re-treatment interval is 15 days.
Delegate WG 25% spinetoram 315 to 420 g/ha (126 to 168 g/acre) 1
  • Group 5
  • Do not apply more than 3 times per season.
  • Minimum re-treatment interval is 12 days.

Entrust SC 

240 g/L spinosad 333 to 444 mL/ha (133 to 178 mL/acre). 1
  • Group 5
  • Minimum re-treatment interval is 5 days.
  • OMRI approved for organic production.
  • Do not apply more than 3 times per year

Exirel

100 g/L cyantraniliprole 1000 to 1500 mL/ha (400 to 600 mL/acre) 3
  • Group 28
  • Use enough water to obtain good coverage.
  • Do not apply more than 4 times per season or a maximum of 4.5 L/ha (1.8 L/acre). 
  • Tank mixes and sequential applications with strobilurin (Pristine, Cabrio), copper and captan fungicides are not recommended as crop injury has resulted under lab settings.
Harvanta 50 g/L cyclaniliprole 1200 to 1600 mL/ha (480-640 mL/acre) 1
  • Group 28
  • Do not apply more than 2 times consecutively or more than 2 times within a single generation of the target pest
  • Use a spray volume of 935-1400 L/ha (374-560 L/ac) of water
  • Do not apply more than 3 times per year or a maximum of 4.8 L/ha (1.92 L/acre)
Malathion 85E malathion 85% 1000 mL per 1000 L of water 1
  • Group 1B
  • Use a maximum of 1000 L/ha (400 L/ac) of water 
  • Application interval of 7-10 days
  • Do not apply more than 3 times per year
Mako  407 g/L cypermethrin 150 to 175 mL/ha (60 to 70 mL/ac)  2
  • Group 3
  • Use enough water to obtain good coverage
  • Minimum re-treatment interval is 7 days
  • Do not apply more than 2 times per year

 

Success

480g/L spinosad 165 to 220mL/ha (66 to 88 mL/acre) 1
  • Group 5
  • Minimum re-treatment interval is 5 days.
  • Do not apply more than 3 times per year 
UP-Cyde 2.5 EC 250 g/L cypermethrin 245 to 285 mL/ha (98 to 114 mL/acre) 2
  • Group 3
  • Use enough water to obtain good coverage
  • Minimum re-treatment interval is 7 days
  • Do not apply more than 2 times per year

*PHI = Pre-harvest interval

 

Hosts

Fruit and nut trees, and native trees including maple, birches, willow and poplar.

Damage

Leaves

Larvae feed in colonies on the foliage, often skeletonizing leaves and can defoliate entire young bushes.

Branches

Except for the forest tent caterpillar which does not build tents on blueberries, the larvae live in a messy web shelter built around a portion of the bush. Can interfere with picking.

Identification

Larva

Forest tent caterpillars have a row of white diamond shaped markings along the top of their bluish-grey bodies. Western tent caterpillars have a row of blue spots along the top of their bodies with orange spots on each side of that line. Their bodies are generally yellowish-brown, and hairy. Fall webworm caterpillars are covered with yellow-orange hair growing from black and orange bumps.

Adult

The adult form of these caterpillars are moths. They fly at night and are rarely seen.

Life History

The western tent caterpillars make tents from May to June whereas the fall webworm has tents from mid-July to mid-September. The forest and western tent caterpillars overwinter as rings of egg masses on one year old wood. The fall webworm overwinters in the pupal stage in debris on the ground or in the soil.

Management

Cultural Control

Prune out twigs with egg masses during the dormant season.

Prune and destroy tents containing the caterpillars while tents are small.

Biological Control

Bacillus thuringiensis (Dipel, Foray, Bioprotec) applied during the season to control other caterpillars will also control young tent caterpillars. Bt is not toxic to bees or other beneficial insects when applied during bloom.

Chemical Control

There are no insecticides registered to control these pests on blueberries. Dormant oil sprays applied from January until mid-February to control scale will also kill tent caterpillar egg masses.

Insecticide sprays applied to control other pests will also control young tent caterpillars. The fall webworm usually appears after harvest: control is not necessary unless populations are high. Spot treatments of infested bushes can be done.

Panel Body

Hosts

Almost all small fruits and ornamentals.

Damage

Roots

Larvae feed on and girdle the roots, rootlets and basal crown area and are especially harmful to young plants. The larvae are the most damaging stage.

Leaves

Adults feed at night on leaves, notching the leaf edges.

Bush. Stunted, poor yields, and may die.

weevils

Identification

Blueberries are mainly attacked by black vine weevils. The following description is for this insect. Obscure and strawberry root weevils have similar life cycles to black vine weevils and are about one-half the size.

Larva

White with brown heads, legless, C-shaped, up to 1.3 cm long when fully grown.

Adult

Black to grey-black beetles with curved snouts, often orange or yellow specks on wing covers, about 1.3 cm long, and a hardshelled body.

Life History

Overwinters in the soil as larvae or as adults. Adults emerge from the soil beginning in late April. Large numbers emerge in late June. The beetles do not fly but are strong walkers and invade new plantings during July and August. They begin to lay eggs in or on the soil in early June and continue until mid-September. Upon hatching, the larvae work through the soil and begin feeding on the roots.

Monitoring

Start to watch for characteristic leaf notching in late April. Be especially observant in early May and early July of bushes that are close to older plantings or weedy headlands.

At night, inspect foliage of plants with notching using a flashlight, especially on warm, still evenings. Adults will readily fall from the bush — place a white sheet under bush and shake vigorously. During the day, inspect under plant debris and in cracks in the soil. Lay boards on the soil for weevils to hide under. Lift up every few days and inspect for adults.

Management

Cultural Control

Check the field history before planting. Root weevils will attack newly planted blueberries if present on the previous crop grown in the field. To reduce weevil population, plant infested fields to a non-host crop, such as cereal cover crops, for 12 to 16 months before planting blueberries.

Plant stock that is free of weevils.

Control weevils in vegetation and ornamentals planted adjacent to the blueberry field, if appropriate.

Chemical Control

Apply control measures only if leaves have fresh leaf notches or the field has a confirmed history of weevil infestation. For best results, begin an adult control program when most of the adults have emerged from the soil in the spring to early summer but before they begin to lay eggs. It can take 3 to 5 weeks from emergence to egg laying. Sprays will be most effective if applied at night.

Use one of the following:

Chemical Control of Weevils
Product Active Ingredient Rate PHI* Comments
Actara 25WG 25% thiamethoxam 210 to 280 g/ha (84 to 112 g/acre) 3
  • Group 4A
  • Use sufficient water to obtain coverage of foliage.
  • This product is highly toxic to bees exposed to direct treatment or to residues on blooming crops and weeds.
  • Do not apply Actara or allow it to drift onto blooming plants if bees are visiting the treated area.
  • After application, wait at least 5 days before placing bees in the treated field.
  • Apply when weevils or weevil damage is detected.
  • Use the higher rate for heavy infestations.
  • Repeat application if insect populations rebuild.
  • Do not apply more than twice per season.

Exirel

100 g/L cyantraniliprole 1000 to 1500 mL/ha (400 to 600 mL/acre) 3
  • Group 28
  • Use enough water to obtain good coverage. 
  • Use the high rate when pest pressure is heavy.
  • Do not apply more than 4 times per season or a maximum of 4.5 L/ha (1.8 L/acre). 
  • Tank mixes and sequential applications with strobilurin (Pristine, Cabrio), copper and captan fungicides are not recommended as crop injury has resulted under lab settings.
Malathion 85 E 85% malathion 1.0 L/ha (400 mL/acre) 1
  • Group 1B
  • Use 1000 L/ha of water.
  • Spray bushes for thorough coverage.

*PHI = Pre-harvest interval (days)

Admire as applied for aphid control will also help to suppress weevils if adults are present at time of spraying.

 

Other Blueberry Pests

 

Birds can cause serious crop losses by eating or “pecking” the fruit before harvest. Understanding the birds’ feeding behavior can help when planning a control strategy.

The use of scaring devices is regulated by the Farm Practices Protection (Right to Farm) Act. For more information on birds and their control, and on the regulations, refer to the "Birds" section of the Berry Management Guide: Pest Management (PDF).

Damage

The incidence of calyx contaminants is very low in the Fraser Valley. However, berries harbouring calyx contaminants can be downgraded or rejected by buyers.

Identification

The major contaminants of blueberry calyxes are the egg sacs of spiders (dwarf and comb-footed), and pupae of lacewings and syrphid flies. Contaminants usually appear as a white “furry” mat in the calyx end of the fruit.

Life History

Spiders and lacewing and syrphid larvae eat or parasitize other insect pests and are considered “beneficials.” Contaminants appear in calyxes of blueberries, from mid-June until early August. Studies have not found a pattern of occurrence linked to time of season, location in the field or on a plant, plant variety, vegetation management or insecticide use.

Management

Cultural Control

The best way to manage this problem is to try and remove contaminated fruit on the grading lines.

Chemical Control

Control sprays are not recommended. Sprays against the egg sacs or pupae found in calyxes are usually ineffective, and may result in outbreaks of thrips, mites, aphids and caterpillars.

 

Snails are slug-like creatures with protective shells. The shells can be up to 2 cm in diameter and have yellow and brown rings. Snails climb into the blueberry bushes and eat the moss and lichens on the branches. Occasionally they eat the leaves and berries. Their protective shells allow them to stay in the bushes during the day.

Snails can end up with the picked berries, especially when mechanically harvesting. Snails that are the size of blueberries cannot be removed mechanically and can end up in the pack.

Cultural Control

Control weeds and keep cover crops mowed as tall grasses and weeds provide protection and may attract these pests.

Chemical Control

If present in large numbers, control snails in the spring before they climb into the plants. When the pests are active and conditions dry, apply in the evening at the base of plants or to the headlands.

Sluggo or Ferramol (0.76% ferric phosphate) slug and snail bait at 25 to 50 kg/ha (10 to 20 kg/acre) scattered by hand or granular applicator between the rows and near the base of the plants when snails are detected. Apply the highest rate if infestation is severe. Re-apply at least every two weeks if snails continue to be a problem. Do not place in piles.

Note: ferric phosphate is not harmful to pets, birds or wildlife.

 

Blueberry Disease Management

Rates of fungicides recommended are for mature blueberry plantings unless otherwise specified. Reduced amounts of spray volume should be applied for smaller, immature bushes. For small area applications refer to the Berry Production Guide: Sprayer Calibration (PDF).

Damage

Alternaria fungus can cause fruit rot and leaf spot. Leaf spot is not usually a serious problem except that leaf spots will produce spores during cold, wet periods which then can cause fruit infections.

Symptoms

Leaf spots are small (1 to 5 mm wide) and light brown to grey with a brownish red border. Infected fruit becomes soft with a flat, fuzzy greenish-black mould which contains many spores. Fruit can begin to rot before and after harvest.

Disease Cycle

The Alternaria fungus overwinters on the ground, on and in twigs, and on plant debris. Infected tissues produce spores during the spring which are transferred to fruit by wind and other means. Fruit infection may occur before harvest or during the post-harvest period.

Monitoring

During the spring, check for leaf infections if weather has been cool and wet. High levels of disease development on leaves may promote fruit infection. Watch the crop closely during harvest. If fruit infection was severe, watch for leaf symptoms the following spring.

Management

Cultural Control

The most important control measure is to cool fruit rapidly after harvest. Do not let fruit become over-ripe. Minimize wounding or bruising during the harvesting operation.

Biological Control

None.

Chemical Control

Where Alternaria fruit rot has been a problem, apply fungicides at green tip, pink bud and petal fall. For control of alternaria leaf spot, apply at green tip, pink bud and petal fall.  Use one or more of the following:

Chemical Control of Alternaria Leaf Spot and Fruit Rot (Alternaria spp.)
Product Active Ingredient Rate PHI* Comments

Bravo 500

or

Bravo 720/ Echo 720

500 g/L chlorothalonil

 

720 g/L chlorothalonil

7.2 L/ha (2.9 L/acre)

 

5.0 L/ha (2.0 L/acre).
54
  • Group M
  • Apply in 1000 L/ha (400 L/acre) of water.
  • If the bushes are small, reduce spray volume appropriately. 
  • Do not re-enter treated areas within 48 hours of application.

Inspire Super

86 g/L difenoconazole, 249 g/L cyprodinil 836 to 1475 ml/ha (338 to 597 ml/acre) 1
  • Group 3 + 9
  • Use a minimum of 200 L/ha (81 L/acre) of water.
  • Do not apply more than two consecutive treatments of Inspire Super before alternating with another fungicide with a different mode of action.  
  • Do not use more than 5.9 L/ha (2.4 L/acre) per crop per season. 

*PHI = Pre-harvest interval (days)

Other fungicides registered for Mummy Berry, Anthracnose and Botrytis fruit rot will help protect against Alternaria.

Damage

Anthracnose is present at low to moderate levels in all blueberry production areas in B.C., but not on all farms. Under warm and wet conditions, the fungus causes primarily pre- and post-harvest fruit rot, but can also cause shoot and blossom blight and stem canker. The fungus often spreads from infected berries to healthy berries during and after harvest leading to significant post harvest losses.

Symptoms

On berries, infected areas initially appear as soft, sunken spots near the calyx (blossom)-end of the fruit. As the disease progresses, the fungus produces salmon to orange coloured masses of spores on sunken fruit surfaces which become more apparent on harvested fruits.

Heavy infections on flower buds and young twigs can cause shoots and blossoms to turn brown to black colour. Stem cankers are rare, but brown to black sunken lesions of 1/8” in diameter with raised margins can appear on stems under favourable conditions.

Disease Cycle

The pathogen Colletotrichum acutatum over winters in or on live twigs and flower buds, and also on dead twigs, spurs and fruit trusses. In the spring, the fungus produces spores which get splashed onto flowers and developing fruits mainly by rain and overhead irrigation. At least twelve hours of continuous leaf wetness at temperatures between 12 to 27o C is required for new infections to occur. Some infection may also occur at cooler temperatures.

Infected young shoots and blossoms may show blight and die-back like symptoms. Berries are susceptible to infection at all stages in their development. The fungus remains dormant on the developing berries until berries begin to ripen. Spent fruit trusses can be infected after harvest.

Monitoring

Watch the crop during harvest for symptoms of the disease.

Management

Cultural Control

Prune to allow good air movement. This speeds up the drying of plants after a rainfall.

Where possible, avoid overhead irrigation. If using overhead irrigation, sprinkle in the early morning so plants dry during the day.

Cool fruit as soon as possible after harvest and store at cool temperatures to slow down rot.

Spores can be spread on totes, flats and harvesting machines. Where possible, avoid introducing anthracnose to the farm through infested totes and flats. Do not take a harvester from an infected field to a healthy field.

Chemical Control

Where anthracnose has been a problem, apply fungicides from bloom through berry development at 7 - 21 day intervals. Use the shorter spray interval when disease pressure is high.  Time application to provide protection when conditions are wet and average temperatures are above 15ºC. Alternate the use of fungicides from different chemical groups to delay the development of resistance.  Use one or more of the following:

Chemical Control of Anthracnose
Product Active Ingredient Rate PHI* Comments

Allegro 500

40% fluazinam 2.24 L/ha (0.9 L/acre) 30
  • Group 29
  • Use 300 to 1000 L/ha (120 to 400 L/ac) of water.
  • Do not apply more than twice in succession.
  • Do not apply more than 4 times per season. 
Aliette WDG 80% fosetyl-Al 5.6 kg/ha (2.2 kg/acre) 1
  • Group 33
  • Use 300 to 1000 L/ha (120 to 400 L/acre) of water.
  • Begin sprays at the pink bud stage and continue on a 14 to 21 day interval.
  • Do not apply more than twice in succession.
  • Do not apply more than 4 times per year.

Bravo 500

or

Bravo 720/ Echo 720

500 g/L chlorothalonil

 

720 g/L chlorothalonil

7.2 L/ha (2.9 L/acre)

 

5.0 L/ha (2.0 L/acre).
54
  • Group M
  • Apply in 1000 L/ha (400 L/acre) of water.
  • In unusually mild springs, apply at green tip and pink bud and petal fall, otherwise apply only at petal fall.
  • If the bushes are small, reduce spray volume appropriately. 
  • Do not re-enter treated areas within 48 hours of application. 
Cabrio EG   20% pyraclostrobin 1.0 kg/ha (400 g/acre) 1
  • Group 11
  • Use enough water (up to 1000 L/ha) to get good coverage.
  • Apply beginning at full bloom and continue through early fruit development.
  • Do not apply more than 4 times per season. Allow at least 10-14 days between applications.
  • Do not apply more than twice in succession.

Confine Extra

53% mono and di-potassium salts of phosphorous acid 4.0 to 5.0 L/ha (1.6 to 2.0 L/acre) 1
  • Group 33
  • Use enough water to provide coverage.
  • Begin sprays when conditions are favourable for disease and continue on a 7 to 21 day interval.
  • Do not apply more than twice in succession.
  • Do not apply more than 5 times per year.

Inspire Super

86 g/L difenoconazole, 249 g/L cyprodinil 1161 to 1475 ml/ha (470 to 597 ml/acre) 1
  • Group 3 + 9
  • Use a minimum of 200 L/ha (81 L/acre) of water.
  • Apply in early bloom.
  • A second application can be made 7 to 10 days later.
  • Do not apply more than two consecutive treatments of Inspire Super before alternating with another fungicide with a different mode of action.  
  • Do not use more than 5.9 L/ha (2.4 L/acre) per crop per season.  

Pristine WG

25.2 % boscalid, 12.8 % pyraclostrobin 1.3 to 1.6 kg/ha (0.52 to 0.64 kg/acre) 0/1
  • Group 7 + 11
  • Use enough water to obtain good coverage.
  • Apply at full bloom through fruit development.
  • Do not apply more than 4 times per crop per season.
  • Do not apply Pristine or other products containing Group 7 or 11 fungicides more than twice in succession.
  • Do not re-enter treated fields for hand harvesting within 1 day of application.
  • If mechanical harvesting, application can be made up to the day of harvest
Quash 50% metconazole 180 g/ha (72 g/acre) 7
  • Group 3
  • Use enough water to obtain good coverage.
  • Apply at bloom. 
  • Do not apply more than 3 times per year.
  • Do not make more than 2 sequential applications. 
  • Do not apply more than 540 g/ha (216 g/acre) per season.

Quilt

125 g/L propiconazole, 75 g/L azoxystrobin 1.0 L/ha (0.4 L/acre) 30
  • Group 3 + 11
  • Use enough water to obtain good coverage.
  • Do not apply more than 3 times per season.

Switch 62.5 WG

37.5% cyprodinil and 25% fludioxinil 775 to 975 g/ha (310 to 390 g/acre) 1
  • Group 9 + 12
  • Use 500 to 1000 L/ha (200 to 400 L/acre) of water to obtain good coverage
  • Do not apply Switch more than twice in succession

*PHI = Pre-harvest interval (days)

Damage

Root rot caused by the fungus, Armillaria, is not widespread in B.C. blueberry fields, but in recent years the incidence has increased. It can cause substantial damage to blueberries.

Symptoms

Plants infected with Armillaria can express a range of symptoms, depending on the age and vigour of the plant and soil conditions. Generally, symptoms are slow to develop and can take a few years to express. Plants may show initial symptoms of nutrient deficiency followed by a gradual decline/dieback over several years.

Affected plants tend to have small, chlorotic leaves and produce less fruit. Severely infected plants lose vigour, wilt and die. Infection may confined to a localized area or randomly spread throughout the field, depending on the distribution of the pathogen in the soil.

Disease Cycle

Armillaria is known to infect nearly five hundred plant species, mostly woody perennials. The fungus is most likely to be present in fields that are adjacent to wooded areas or have recently been cleared. Armillaria survives as mycelial strands or shoestring-like structures called “rhizomorphs” and thrives on organic debris and decaying roots and stumps. Infection of blueberry roots occurs, primarily, when roots come in contact with rhizomorphs.

Further spread of the fungus between infected and healthy plants is by root-to-root contact. If the infection is confined to the roots plants show gradual decline over several years. However, if the fungus girdles the crown, then decline and death is rapid.

Monitoring

In late spring and summer, look for early symptoms of nutrient deficiency and reduced plant vigour. The growth of Armillaria is often visible as pale-yellow or white, thread-like mycelium and/or dark-brown to black rhizomorphs beneath the bark of the infected roots and base of the stem or trunk region. In late summer and fall, if conditions are favourable, the fungus may produce yellowish brown mushrooms at the base of the affected plants.

Management

Cultural Control

Newly cleared fields selected for blueberry planting should be thoroughly worked and all stumps, root pieces and decaying wood materials removed. Newly cleared fields should be left fallow for at least two to three years or cropped to annual non-host crops to reduce the inoculum of the fungus. Soil fumigation can be used to further reduce or eliminate the fungus. Fungal inoculum found in the deeper soil may not be killed by fumigation.

In established fields, infected plants, including the trunk and all roots should be removed and burned. Examine all adjacent healthy plants and remove them if infected or suspected of infection. Soil fumigation of the infected area helps to reduce the inoculum and spread of the fungus. Avoid using sawdust mulch in and around infected area.

Biological Control

None.

Chemical Control

None.

Damage

Mosaic is becoming more common in B.C. blueberry fields. Losses due to this condition are difficult to assess, but reports from other regions show a 15% yield reduction on mosaic-infected Bluecrop.

Symptoms

Affected leaves show mild to bright mottle and mosaic patterns of chrome yellow, yellow, and yellow green. Infected leaves may also show areas of pink colouration. Mottle and mosaic symptoms may vary depending on the blueberry variety. Mosaic symptoms typically appear on basal shoots only. However, in some cases, symptoms can be seen on the whole bush. Detection is difficult as infected bushes do not always have symptoms each year. Fruits on diseased bushes ripen late and are poor quality.

Disease Cycle

The disease cycle of blueberry mosaic virus is not fully understood. Blueberry aphids may play an important role as a vector in virus transmission and spread in the field. The virus may be carried on planting stock as well.

Monitoring

Pay close attention to and do periodic scouting for symptoms on leaves. Monitor and manage blueberry aphid populations. Mosaic virus is difficult to confirm and can be confused with other disorders. Graft-transmission is the only test available to confirm the presence of mosaic. This is an expensive procedure and not frequently used.

Management

Cultural Control

Use virus-free planting stock. Prune and fertilize to maintain good vigour Removing infected plants is the only control but may not be cost-effective.

Biological Control

None.

Chemical Control

None.

Damage

This disorder was first described in B.C. in 2000. It causes partially developed fruit to drop prematurely resulting in virtually no fruit production on affected plants.

Symptoms

At bloom, red streaking appears on new leaves and developing flowers. As the season progresses the red colouration of the leaves disappears and by harvest time no visible foliar symptoms can be observed. Fruit initially develops normally, but only attains a size of 3-5 mm and usually drops several weeks prior to harvest.

Because there is no fruit load, affected plants are much more vigorous and upright than healthy plants and can be easily identified at this time. Any fruit that is retained on affected bushes is often misshapen. Symptoms recur every year on affected plants. This condition has been observed only in the Bluecrop variety.

Disease Cycle

This disorder spreads from year to year within affected fields. The causal agent has not been determined yet. Research is underway to identify the causal agent of the disorder.

Monitoring

Inspect fields at bloom for red streaking on the leaves and/or blossoms. Following fruit set look for plants which drop immature berries. At harvest watch for individual plants which are particularly vigourous, upright and stand above the field canopy.

Management

Cultural Control

Remove affected plants.

Damage

Blueberry scorch, caused by Blueberry scorch virus (BlScV), is a serious disease that was first detected in B.C. in 2000 and has since become widespread in all blueberry production regions. BlScV can spread by as much as 5% annually in infected fields. Damage caused by BlScV can be severe, resulting in significant yield losses on infected plants. Plants do not recover.

Symptoms

Symptoms of BlScV infection may not develop for one or more years following infection (latent period). Symptoms usually appear during bloom, and may include blighting of blossoms and young leaves, leaf chlorosis and dieback. While blossoms and/or leaves may be blighted, the shoot tissue remains green.

On some varieties, blighted blossoms may be retained on the bush into the following year. Subtle symptoms may be observed on some varieties, most notably Bluecrop. These symptoms can include yellowing of leaf margins or leaf mottling, overall pale color, low number of blossoms and a twiggy appearance to the bush. Sometimes red line patterns may develop on the leaves of infected cultivars in the fall. Infected plants have decreased or no fruit production.

There are believed to be at least 5 different strains of BlScV present in B.C. These strains are closely related to the East Coast and Northwest strains and more research is needed in evaluating their impacts on different blueberry varieties.

Disease Cycle

In BlScV-infected plants virus levels are highest in the buds during the spring and numbers decrease rapidly as the plant grows. BlScV is transmitted non-persistently by aphids. The virus does not replicate in the aphid and it must be transmitted fairly quickly to new plants in order to survive. The resident aphid of highbush blueberry (the Blueberry aphid, Ericaphis fimbriata) and migrant aphids (aphid species that feed briefly on blueberry while moving from one crop to another) have both been shown to transmit BlScV.

BlScV can also be transmitted through infected planting stock. A cutting taken from an infected plant will be infected with BlScV. Since propagation materials are widely distributed, this mode of virus transmission can be very serious, resulting in long-distance spread of BlScV.

Monitoring

Fields should be closely monitored for symptoms of BlScV starting during bloom. Laboratory testing is needed to confirm the presence of BlScV. If any suspicious symptoms are observed, submit a sample to the BCAGRI Plant Diagnostic Laboratory consisting of about 10 healthy green leaves from around the symptomatic area. Flag the sampled bushes so they can be located again should removal be necessary. Samples can be collected from plants showing suspicious symptoms from bloom until late-August.

Fields should be monitored for aphids. See Aphids in this section.

Management

Cultural Control

Only use virus-free planting stock that has been grown according to an accepted propagation protocol includes virus testing.

Manage aphids. See Aphids in this section.

Remove infected plants including the root system. Infected plants will act as a source of new infection for surrounding healthy plants, as long as they remain in the field.

Biological Control

None.

Chemical Control

None.

Damage

Shock virus was first detected in B.C. in 2001. It has since been found in many fields throughout the Fraser Valley.

Symptoms

Blossoms and new shoots blight at early bloom. At this stage, scorch virus and shock virus symptoms may look the same although shock symptoms usually occur earlier in the season. Plants recover and later in the season produce a second flush of growth.Infected bushes appear normal by late summer, although there will be little fruit. All varieties appear to be susceptible, but Berkeley, Bluegold, and Bluetta are very susceptible.

These symptoms occur for 1 to 4 years and then the plant appears to recover. A good crop can be produced in well-managed fields although recovered plants are still infected with the virus. Pollen produced from these plants is contaminated with the virus. Thus, the virus can spread to nearby healthy bushes during pollination.

Disease Cycle

It is spread by infected planting stock and by insects carrying infected pollen to healthy plants.

Monitoring

Watch for symptoms of the virus at early bloom. Laboratory testing is necessary for correct identification. If any suspicious symptoms are observed, submit a sample consisting of 10 healthy green leaves from around the symptomatic area to the BCAGRI Plant Diagnostic Laboratory. Flag the sampled bushes, should control be necessary. Samples can be collected from plants showing suspicious symptoms from bloom until late-August.

Management

Cultural Control

Only use virus-free planting stock that has been grown according to an accepted propagation protocol includes virus testing.

There are no known resistant varieties.

Do not establish new plantings next to virus-infected fields.

Biological Control

None.

Chemical Control

There are no chemical controls.

Damage

This disease can be damaging under cool, wet conditions. Severely infected flower buds and canes can reduce yields. Young plants may be killed if lesions are extensive. Frost and winter injury on plant tissues encourages bacterial entry into plants and increases blight severity.

Symptoms

Symptoms first appear in late winter on young canes as water-soaked lesions. These lesions develop into irregular brownish-black areas up to a few millimeters long which can expand to the entire length of one-year-old canes. Buds found within these lesions on infected canes are killed and stems may become girdled. Flower buds may be killed before they fully open. Spring frosts often accelerate bacterial blight incidence and severity. The disease also attacks young plants and cuttings in propagation beds.

Disease Cycle

This disease is caused by the bacterium Pseudomonas syringae pv. syringae. The bacterium lives on plant surfaces, e.g. stems and buds, but it can only cause damage after it gains entry into the plant. It enters through natural openings, wounds, and frost- and winter-damaged tissues.

Once the bacterium gains entry, under favourable conditions, it multiplies and spreads internally. Most strains of this bacterium kill plant tissues by producing plant toxins. At below freezing temperatures, the bacterium also produces a protein which triggers ice nucleation resulting in freezing damage to plant tissues. Freeze damaged tissue can be more prone to secondary infection.

Monitoring

Look for symptoms of the disease during pruning to determine if fall copper sprays will be required.

Management

Cultural Control

Prune out and remove diseased wood, especially before fall rains, to reduce the chance of new infections.

Apply the appropriate amount of nitrogen based on tissue test results. Over-fertilization or N applications after mid-July can cause overly vigorous growth which is very susceptible to fall infection.

The Duke, Bluecrop, Patriot, Brigitta, Jersey and Bluetta varieties are susceptible. Elliott, Rancocas and June have shown some resistance. Bluecrop, Patriot, Brigitta and 1613A appear to be more susceptible to blossom blight than others.

Biological Control

None.

Chemical Control

Surveys in 2000 and 2001 have shown that copper tolerant strains of the bacterium exist in some fields. Copper applications to fields with tolerant bacteria will increase copper tolerant populations which may result in higher disease levels. Higher copper rates will not provide better control and will increase the risk of plant damage in the spring. Repeated copper applications over time will continue to select for more copper tolerant strains in the field. Alternatives to copper are being explored.

Chemical Control of Bacterial Blight
Product Active Ingredient Rate PHI* Comments

Copper Oxychloride 50

Copper Spray Fungicide

50% copper oxychloride 2 to 4 kg/ha (0.8 to 1.6 kg/ac) 2
  • Group M2
  • Use 500 to 1000 L/ha (200 to 400 L/ac) of water
  • Use a spreader sticker
  • Apply the high rate (4 kg/ha) once before fall rains and again at 50% leaf fall.
  • Apply the low rate (2 kg) in the spring at bud burst and at two week intervals if the weather is cool and wet
  • Apply under fast drying conditions to reduce the risk of plant injury. Avoid application on cool, cloudy days.
  • Maximum of 6 applications per year.
  • Do not re-enter treated fields within 48 hours of application. 
Cueva Copper octanoate 1.8% 470-940 L/ha (188-377 L/acre) 1
  • Group M1
  • Use in a 0.5 % to 2% solution
  • Apply at the start of flowering and continue every 7 to 10 days.

Serenade Opti 

QST 713 strain-Bacillus subtilis 0.6 to 1.7 kg/ha (0.24 to 0.68 kg/acre) 0
  • Group 44
  • Use enough water to obtain thorough coverage.
  • Apply before fall rains and again during dormancy before spring.  
  • Approved for organic production

*PHI = Pre-harvest interval (days)

Damage

The fungus Botrytis occasionally causes significant losses especially if wet weather occurs during bloom, fruit ripening or harvest. Infected fruit often does not develop symptoms until after harvest which creates dissatisfaction with retailers and consumers.

Symptoms

Twigs infected by Botrytis appear grey and dried-up. Grey, fuzzy growth can be seen on infected twigs. Infected blossoms turn brown and dried-up and may resemble symptoms of blueberry scorch or bacterial blight.

Fruit rot symptoms often are not visible until after harvest when the distinctive grey, fuzzy growth develops. Healthy berries next to infected ones quickly become infected. With prolonged wet weather after bloom, old flowers can remain attached to developing berries. Then Botrytis may infect developing berries through the flower tissue. These berries develop purplish, sunken areas where the old flower has stuck. Infected berries usually do not mature.

Disease Cycle

Botrytis is a very common fungus. It cannot be eliminated from fields, only reduced. The fungus overwinters on branch tips, and on dead plants or organic debris on the ground. In the spring, masses of spores are produced on this material and carried by wind currents to new blueberry growth.

Blossoms, twigs and fruit can be infected under periods of high relative humidity (>95%) and cool temperatures (15-20°C). Twigs damaged by cold are more susceptible to infection. The fungus enters through blossoms and may remain in a dormant state until the fruit is harvested. The fungus produces numerous spores on infected twigs, blossoms and pre- and post-harvested fruits.

Monitoring

Examine twigs for symptoms of Botrytis infection. Alert workers to symptoms of twig infection and attempt to prune these out where possible.

Watch for infection of blossoms.

Management

Cultural Control

Improve air movement in the plant canopy through selective pruning. Avoid high levels of nitrogen which promotes excessive leaf growth. Carefully time overhead irrigation so plants can dry as quickly as possible. Early morning applications are preferred. Cool fruit as quickly as possible after harvest.

Biological Control

None.

Chemical Control

To guard against losses from fruit rot, protect the blooms with sprays applied at the start of blossom. Repeat sprays in 7 to 10 days and, if necessary, during fruit ripening. To delay development of resistance rotate sprays from the different groups. Use one or more of the following:

Chemical Control of Botrytis Blight and Fruit Rot
Product Active Ingredient Rate PHI* Comments

Captan 50 WP

or

Captan 80 WDG

50% captan

 

80% captan

3.6 kg/1000 L of water/ha (1.44 kg in 400 L/acre)

 

2.0kg/1000L of water/ha (0.8kg in 400L/acre)

2/3
  • Group M
  • Do not re-enter treated fields within 72 hours of application unless protective clothing is worn.
  • For hand harvesting, do not apply within 3 days of harvest.
  • For machine harvest, do not apply within 2 days of harvest.
Cantus WDG  or Lance WDG 70% boscalid 560 g/ha (224 g/acre) 0
  • Group 7
  • Use enough water to obtain good coverage.
  • Do not apply more than 4 times per crop per season.
  • Do not apply Group 7 fungicides more than twice in succession. 
Elevate 50 WDG 50% fenhexamid 1.7 kg/ha (0.7 kg/acre) 1
  • Group 17
  • Use enough water (up to 1000 L/ha) to obtain good coverage.
  • Apply up to 4 times per season
  • Do not make more than two consecutive applications

Ferbam 76 WDG

76% Ferbam 3.75 kg/1000 L 40
  • Group M
  • Use a minimum of 500 L/ha (202 L/acre) of water.
  • Do not apply more than twice per crop per season for Botrytis.  
  • Not acceptable to some markets. Check with your packer before using
Fontelis 200 g/L penthiopyrad 1.0 to 1.75 L/ha (0.4 to 0.70 L/ac) 0
  • Group 7
  • Use a minimum spray volume of 100L/ha (40L/ac) 
  • Begin applications prior to disease development and continue on a 7 to 10 day interval
  • Use the higher rate and shorter interval when disease pressure is high
  • Make no more than 2 sequential applications
  • Maximum 5 applications and 5.25 L/ha (2.1 L/ac) per season
Inspire Super 86 g/L difenoconazole, 249 g/L cyprodinil 1033 to 1475 ml/ha (418 to 597 ml/acre) 1
  • Group 3 + 9
  • Use a minimum of 200 L/ha (81 L/acre) of water.  
  • A second application can be made 10 to 21 day later.
  • Do not make more than two applications per crop per season for Botrytis.

Kenja 400SC

400g/L Isofetamid 0.99 to 1.24  L/ha (400 to 500 mL/acre) 7
  • Group 7
  • Do not use more than 2 consecutive applications of isofetamid or other group 7 fungicide.
  • Do not use more than 3 applications per year
Luna Tranquility 125 g/L fluopyram, 375 g/L pyrimethanil 1200 ml/ha (486 mL/acre) 0
  • Group 7 + 9
  • Use a minimum of 500 L/ha (202 L/acre) of water.
  • Do not apply more than twice per crop per season for Botrytis.  
Luna Privilege 500 g/L fluopyram 500 mL/ha (200 mL/acre) 0
  • Group 7
  • For post-harvest disease control, make last application close to  harvest
  • Do not apply more than 2 applications per season or a maximum of 500g of fluopyram 
  • Do not use more than  2 consecutive applications of group 7 fungicides
Maestro 80 DF 80% captan 2.25 kg/1000 L of water/ha (0.9 kg in 400 L/acre) 2é3
  • Group M
  • Do not re-enter treated fields within 72 hours of application unless protective clothing is worn.
  • For hand harvesting, do not apply within 3 days of harvest.
  • For machine harvest, do not apply within 2 days of harvest.

Diplomat 5 SC

5% Polyoxin D zinc salt 463 to 926 mL/ha (185-370mL/acre) 0
  • Group 19
  • Use enough water to obtain good coverage.
  • Do not apply more than 150g a.i/ha per season
Pristine WG 25.2 % boscalid, 12.8 % pyraclostrobin 1.3 to 1.6 kg/ha (0.52 to 0.64 kg/acre) 0
  • Group 7 + 11
  • Use enough water to obtain good coverage.
  • Do not apply more than 4 times per crop per season.
  • Do not apply Pristine or other products containing Group 7 or 11 fungicides more than twice in succession.
  • Do not re-enter treated fields for hand harvesting within 1 day of application.
  • If mechanical harvesting, application can be made up to the day of harvest
Regalia 20% extract of R. sachalinensis 0.125 - .0.25% v/v in 400 to 800 L/ha (160 to 320 L/acre) of water 0
  • Group P5
  • Bacterial-based fungicide, provides suppression of fruit rot.
Scala 400g/L pyrimethanil 2.0 l/ha (0.78 l/acre) 0
  • Group 9
  • Use a minimum spray volume of 1000 l/ha (393 l/acre).
  • Do not apply more than 2 times per crop per season.  
Sercadis  300 g/L fluxapyroxad 250-666 mL/ha (100-266 mL/acre) 0
  • Group 7
  • Use enough water to obtain good coverage.  
  • Do not apply more than 3 times per crop season.
  • Provides suppression of Botrytis 
Serenade Opti QST 713 strain-Bacillus subtilis 1.7 to 3.3 kg/ha (0.68 to 1.32 kg/acre) 0
  • Group 44
  • Bacterial-based fungicide, provides suppression of fruit rot.
Switch 62.5 WG 37.5% cyprodinil and 25% fludioxinil 775 to 975 g/ha (310 to 390 g/acre) 1
  • Group 9 + 12
  • Use 500 to 1000 L/ha (200 to 400 L/acre) of water.
  • Do not apply more than twice in succession.
  • Alternate with fungicides from other groups.

Timorex Gold 

23.8% tea tree oil 1.5 to 2.0 L/ha (0.6 to 0.8 L/acre) 2
  • Group 46
  • Use 400 to 800 L/ha (160 to 320 L/acre) of water.
  • Avoid spraying in the heat of the day or when temperatures are above 35ºC.

*PHI = Pre-harvest interval (days)

Damage

This disease is usually of minor importance but can be an issue in the nursery.

Symptoms

It is characterized by the presence of dark brown, rough galls on the roots, crown, stems and branches. The galls are normally round but they may appear as elongated structures on branches where several galls have grown together. Stems may be girdled by crown gall. Leaves above the infection may turn red and look similar to Godronia canker “flags.” Symptom development is often worse following winters where cold injury has occurred.

Drawing of roots infected by crown gall

Disease Cycle

Crown gall is caused by a bacterium. It is introduced into the plant as infected cuttings or through wounding. A common method of introduction is on infested pruning shears.

Monitoring

Look for swellings at the crown or along the branches. Use fluorescent tape to identify infected plants, and show pruners how to reduce the risk of contaminating healthy plants after working on infected ones.

Management

Cultural Control

Obtain clean nursery stock.

If galls are found on established bushes, prune out and destroy infected stems. Take precautions to avoid spreading the disease on the pruning shears. Disinfect pruning shears after each cut by dipping them in a solution of 5% Virkon, Chemprocide or CleanGrow (16 mL/L) or a 1:10 dilution of household bleach.

Caution: bleach will corrode metal. Make fresh solutions frequently as the pruning shears will not be disinfected if the water is dirty.

Control weevils as the crown gall organism can enter the blueberry plants through weevil feeding wounds.

Biological Control (pre-plant only)

Dygall is a formulation of a naturally occurring bacterium that attacks the crown gall bacterium. It is applied to cuttings or plant roots before planting in infested soils. Dygall may be ordered from:

Mori Nurseries Ltd.

(416) 468-3218.

Only trained nursery personnel should use this product.

Chemical Control

None.

Damage

Godronia or Fusicoccum canker is the most serious canker disease of blueberry in B.C. Disease incidence seems to be increasing in recent years. Branches on affected plants are killed, reducing yields. Plants will die if too many branches are killed.

Symptoms

The leaves of infected branches turn a bright reddish-brown. These so called “flags” clearly stand out, even from a considerable distance, during the growing season.

Disease Cycle

The Godronia fungus overwinters as mycelium in living stems and crowns of infected plants. Small, black dots (pycnidia) that contain spores develop on the previous season’s cankers. The spores are released in wet weather and spread by water. Spores are released from early March to October but most infections occur during wet conditions in spring and fall. Infections usually begin at leaf scars and axils of leaf and flower buds, but may also occur at other openings in the bark. Cankers first appear as small, reddish discolourations on the stem.

As the cankers enlarge, the centres usually become grey and the margins develop a reddish or dark brown colour. The cankers eventually girdle the stem, causing wilting and sudden death. Dead leaves turn a bright reddish-brown and remain attached. This symptom is called the “flag.”

Monitoring

It may take two or more years for complete girdling of the cane to occur. The “flag” in any given year may be the result of infections from several years ago – a point to consider when evaluating the effectiveness of control measures. Infected branches should be pruned out when first observed. Inform pruners of symptoms.

Management

Cultural Control

Prune out and remove all diseased branches.

Prune to promote good air movement around plants.

Try to avoid overhead irrigation in fields with Godronia canker. If overhead irrigation is used, try to schedule irrigation periods early in the morning so plants can dry as quickly as possible.

Duke, Earliblue and Bluecrop are highly susceptible to this disease. The effect on Duke may be more severe as it is slow to produce replacement shoots from the crown. Rubel and Rancocas are resistant.

Biological Control

None.

Chemical Control

There are no fungicides registered for control. Fungicides applied for mummy berry, fruit rot and other diseases may help reduce Godronia infections.

Damage

This fungal disease is a serious disease of blueberries in south-coastal BC. Yield losses can be large if the disease pressure is high and the spring is wet. All varieties are susceptible to mummy berry but they differ in susceptibility to the primary and secondary disease stages.

Symptoms

Spring Symptoms

Developing leaf shoots and flower clusters suddenly droop. Within 24 hours, the upper sides of these shoots and the veins in the leaves turn brown, and then develop a tan-grey fuzz. Secondary spores are produced in the fuzzy area. Bees are attracted by the sugars produced there and spread the secondary fungal spores to flowers. Affected leaves, shoots and flowers eventually fall off the plant. No further symptoms are seen until the berries start to ripen.

Berry Symptoms

Infected berries turn cream to pink and then tan or whitish grey just before they start to ripen. White cottony mycelium can been seen when the berry is cut in half. The infected berries usually shrivel, harden, become pumpkin shaped and fall off the bush before harvest.

Diagram of the lifecycle of a mummy berry

Disease Cycle

Primary Infection

Mummies — the hard, black, pumpkin-shaped form that contain the fungus inside can live for several years in or on the soil. The fungus requires a chilling period during the winter before they can start to produce the trumpet-shaped cups (spore-producing structures called apothecia) in the spring. In late February to March, small cups grow from the mummies and produce spores (ascospores). These are ejected into the air about the time the buds start to open.

The spores infect opening vegetative and flower buds. This stage is called the primary infection. Mummies buried 2.5 cm or more in the ground will not develop spores because the sprout-like structure (stipe) that grows from the mummy must be exposed to light before it can mature into an apothecium. Spores are only produced in the cup (apothecium).

Secondary Infection

Infected buds become watersoaked, wilt and turn brown. A second type of spores (conidiospores) form on the diseased shoots about 3 weeks after the primary infection. These secondary spores are carried by the wind, water and pollinating bees to healthy flowers.

The spores germinate and grow into the base of the flower where the berry will develop. This stage is the secondary infection. Infected berries develop normally until they near maturity. Before harvest, infected berries eventually turn whitish grey, and fall to the ground. Eventually the outside part of the berry decays and the black, pumpkin-shaped berry with fungus within remains on the soil surface.

Monitoring

Starting in mid-February monitor for bud development. Time fungicide applications according to plant growth stage. Start to apply fungicides when 5 mm of green tissue is showing on the leaf buds or when the bud scales are showing on the flower buds. Infection cannot occur before the buds have reached this stage. Continue protective sprays for primary infections until leaf buds start to unroll.

Keep a close watch for the development of primary infections. If seen, apply 1 to 2 additional sprays to protect the opening blossoms from secondary infections. This stage usually occurs between late April and late May depending upon the variety and growing conditions.

Caution: Fruit russetting has been observed when Funginex is applied during 50-80% bloom. These later sprays are not necessary if primary infections are prevented. Therefore, it is extremely important to prevent berry infections by monitoring the field for the development of the plant buds.

Management

Cultural Control

Anything that damages the mummies or the developing apothecia will reduce mummy berry infections. In fields that do not have permanent cover crops between the rows and/or sawdust mulch, mummies may be raked between the rows in early spring. Rotovating or frequent harrowing after raking will bury mummies and destroy developing apothecia. Disease development is usually most severe in low-lying, moist areas, or beside windbreaks where air circulation is poor.

Biological Control

None.

Chemical Control

Timing of fungicide sprays is critical for successful mummy berry control. It is especially important to protect the buds from primary infections. To prevent primary infections, apply the first spray when 5 mm of green tissue is showing on developing leaf buds or when the bud scales are exposed on the flower buds. This usually occurs in March but varies with location and weather conditions.

Repeat the spray in 10 to 14 days  If wet weather continues, a third spray in another 10 to 14 days may be required. These sprays protect the buds but do not kill the apothecia on the ground.  Use one of the following:

Chemical Control of Mummy Berry
Product Active Ingredient Rate PHI* Comments
Actinovate  0.0371% Streptomyces lydicus 425 to 840 g/ha (172 to 340 g/acre) 0
  • Group NC
  • Use 200 to 1400 L/ha (80 to 566 L/acre) of water to obtain uniform coverage.  
  • Repeat applications at 7 to 14 day intervals.  
  • Apply spray within 4 hours of mixing.
  • Bacterial-based biofungicide, provides suppression of mummy berry.
Allegro 500 40% fluazinam 2.24 L/ha (0.9 L/acre) 30
  • Group 29
  • Use 300 to 1000 L/ha (120-400 L/acre) of water
  • Do not apply more than 4 times per season.
  • Provides suppression of mummy berry.
Fontelis 200 g/L penthiopyrad 1.0 to 1.75 L/ha (0.4 to 0.70 L/ac) 0
  • Group 7
  • Use a minimum spray volume of 100L/ha (40L/ac) of water
  • Begin applications prior to disease development and continue on a 7 to 10 day interval
  • Use higher rate and shorter interval when disease pressure is high
  • Make no more than 2 sequential applications
  • Maximum 5 applications and 5.25 L/ha (2.1 L/ac) per season
  • Provides suppression of mummyberry

Funginex DC

190 g/L triforine 3 L/ha (1.2 L/acre) 60
  • Group 3
  • Use in 1000 L/ha (400 L/acre) of water
  • Thoroughly wet the bushes including all buds and shoots. 
  • Do not re-enter treated fields within 48 hours of application. 
  • Fruit russetting has been observed when Funginex is applied during 50-80% bloom

Indar  

75% fenbuconazole 140 g/ha (56 g/acre) 30
  • Group 3
  • Use enough water to obtain good coverage.
  • Do not apply more than 4 times per season. 

Inspire Super 

86 g/L difenoconazole, 249 g/L cyprodinil 558 to 836 ml/ha (226-338 ml/acre) 1
  • Group 3 + 9
  • Use a minimum of 200 L/ha (81 L/acre) of water. 
  • Do not make more than four applications a year.  
Mission 418 EC or Bumper  418 g/L propiconazole 300 mL/ha (120 ml/acre) 60
  • Group 3
  • Use a minimum of 200 L of water per hectare (80 L/acre).
  • Do not use more than 4 applications per year. 
  • Do not re-enter treated fields for pruning within 5 days of application. 
Diplomat 5 SC 5% Polyoxin D zinc salt 463 to 926 mL/ha (185-370mL/acre) 0
  • Group 19
  • Use enough water to obtain good coverage.
  • Do not apply more than 150g a.i/ha per season.

Proline 480 SC

480 g/L prothioconazole 315 to 420 mL/ha (126 to 168 mL/acre) 7
  • Group 3
  • Use enough water to obtain good coverage.
  • Do not apply more than twice per year.
  • Do not apply more than 820 mL/ha (328 mL/acre) per crop per year.
Propulse

200 g/L fluopyram,

200 g/L prothioconazole

750 mL/ha (300 mL/acre) 7
  • Groups 3 and 7
  • Begin applications when scales have separated on 40% of the flower buds
  • Do not apply more than twice per year
  • Do not apply more than 2000 mL/ha (800 mL/acre) per crop per year

Quash 

50% metconazole 180 g/ha (72 g/acre) 7
  • Group 3
  • Use enough water to obtain good coverage.
  • Do not apply more than 3 times per year.
  • Do not make more than 2 sequential applications.
  • Do not apply more than 540 g/ha (216 g/acre) per season.

Quilt

125 g/L propiconazole, 75 g/L azoxystrobin 1.0 L/ha (0.4 L/acre) 30
  • Group 3 + 11
  • Use enough water to obtain good coverage.
  • Do not apply more than 4 times per season.
Regalia Maxx 20% extract of R. sachalinensis 0.125 - .0.25% v/v 0
  • Group P5
  • Use 400 to 800 L/ha (160 to 320 L/acre) of water.
  • Repeat applications at 7 to 10 day intervals.
  • Bacterial-based biofungicide, provides suppression of mummy berry.

Serenade Opti 

QST 713 strain-Bacillus subtilis 2.0 to 3.3 kg/ha (0.8 to 1.32 kg/acre) 0
  • Group 44
  • Repeat applications at 7-14 day intervals.
  • Bacterial-based biofungicide, provides suppression of mummy berry.

Topas 250E or Jade or Tilt 

250 g/L propiconazole 500 mL/ha (200 mL/acre) 60
  • Group 3
  • Use a minimum of 200 L of water per hectare (80 L/acre).
  • Do not use more than 4 applications per year. 
  • Do not re-enter treated fields for pruning within 5 days of application. 

*PHI = Pre-harvest interval (days)

Damage

A serious disease in eastern highbush blueberry growing regions which is becoming more prevalent in BC blueberry fields. When cankers are found, they are often associated with bushes that were wounded or growing under stressful conditions.

Symptoms

Cankers develop on one-, two- and three-year old stems. Cankers on one-year old stems are 5 to 15 cm long—much longer than young Godronia cankers. Older cankers on two- and three-year old stems are grey and somewhat flattened. When the canker girdles the stem, the leaves turn red and remain attached to the stem. The appearance is similar to Godronia canker “flags.”

Disease Cycle

The fungus overwinters inside infected stems and produces spores in the spring. Spore release is triggered by rainfall and may occur from blossom bud swell until late August. Wounded plants are more susceptible to infection.

Monitoring

Watch for the appearance of “flags” during the summer.

Management

Biological Control

None.

Cultural Control

Prune out infected branches by cutting as deep into the crown as possible. Destroy prunings.

Promote good air movement by pruning and controlling weeds.

Chemical Control

Chemical Control of Phomopsis Canker
Product Active Ingredient Rate PHI* Comments

Aliette WDG

80% fosetyl-Al 5.6 kg/ha (2.2 kg/acre)   1
  • Group U
  • Use 300 to 1000 L/ha (120 to 400 L/acre) of water.
  • Begin sprays at the pink bud stage and continue on a 14 to 21 day interval.
  • Do not apply more than 4 times per year.

Allegro 500

40% fluazinam 2.24 L/ha (0.9 L/acre) 30
  • Group 29
  • Use 300 to 1000 L/ha (120 to 400 L/ac) of water.
  • Do not apply more than 4 times per season.

Bravo 500

500 g/L chlorothalonil 7.2 L/ha (2.9 L/acre). 54
  • Group M
  • Apply before disease development. 
  • Do not re-enter treated areas within 48 hours of application. 

Bravo 720 or Echo 720

720 g/L chlorothalonil 5 L/ha (2.5 L/acre) 54
  • Group M
  • Make three applications at green tip, pink bud and petal fall. 
  • Do not re-enter treated areas within 48 hours of application. 
Cabrio EG 20% pyraclostrobin 1.0 kg/ha (0.4 kg/acre) 1
  • Group 11
  • Use enough water (up to 1000 L/ha) to get good coverage.
  • Apply prior to disease development.
  • Do not apply more than 4 times per season.
  • Allow at least 10-14 days between applications.
  • Do not apply more than twice in succession.
Quash  50% metconazole 180 g/ha (72 g/acre) 7
  • Group 3
  • Use enough water to obtain good coverage.
  • Apply before bloom when conditions favour disease. 
  • Do not apply more than 3 times per year. Do not make more than 3 sequential applications.
  • Do not apply more than 540 g/ha (216 g/acre) per season.

Pristine WG

25.2 % boscalid, 12.8 % pyraclostrobin 1.6 kg/ha (0.64 kg/acre) 0/1
  • Use enough water to obtain good coverage.
  • Apply before disease development.
  • Do not apply more than 4 times per crop per season.
  • Do not apply Pristine or other products containing Group 7 or 11 fungicides more than twice in succession.
  • Do not enter treated fields for hand harvesting within 1 day of application.
  • Do not enter fields for all other activities until residues have dried.
  • If mechanical harvesting, application can be made up to the day of harvest.

*PHI = Pre-harvest interval

Damage

Root and crown rot is primarily caused by Phytophthora cinnamomi. It can cause substantial damage to plants grown under wet conditions resulting in decline, yield loss and plant death. In addition to P. cinnamomi, several other soil pathogens, including Pythium spp, notably Pythium sterilum, can also contribute to the severity of the disease.

Symptoms

As a result of root and crown damage, leaves become yellow or reddish as they starve for nutrients. New growth may be stunted, and leaves may develop brown edges. Leaves may also start dropping from the base of the bush upwards. These symptoms are similar to those caused by nutrient deficiencies, Godronia canker or crown gall.

Affected bushes are often grouped together in low-lying or wet areas. Roots are soft and brown under the bark and the entire root system is reduced. As the infection progresses, crown tissue becomes brown under the bark.

Disease Cycle

This species of Phytophthora infects many other trees and shrubs in the Pacific Northwest and is common in soil. Infection is favoured when soils are wet over long periods as a result of compaction, poor drainage or over-irrigation. Warmer temperatures between 20-32°C favour P. cinnamomi. This is a different species from the one that causes raspberry root rot. The raspberry pathogen is favoured by cooler temperatures.

Monitoring

Examine the root system and crown of ailing plants to determine if the roots have been damaged, especially in low areas. Scrape the outer layer of tissue from the root or crown to look for the typical brown colour.

Management

Cultural control

Pre-plant

Select suitable well-drained sites and install subsurface drainage, where needed.

Plant nursery stock at the same depth they were planted in the pots. Deep planting may cause crown death that resembles Phytophthora root rot.

Established Plantings

Carefully manage irrigation. Avoid drought stress but do not overwater and cause roots to be in wet soil for long periods.

Avoid any extra stress on the plants such as fertilizer or herbicide burn.

After heavy rains, observe areas with poor drainage. Improve the drainage in these areas.

Remove plants infected with Phytophthora.

Biological Control

None.

Chemical Control

Soil Drench

Ridomil Gold 480SL or 480EC (480 g/L metalaxyl-M) at 37 ml per 100 m of row. Apply to the soil surface in a one-meter wide band centered over the row in spring just prior to growth. If the row spacing is 3 m (10 ft), use 0.5 L/acre. Rain or irrigation is essential to wash Ridomil into the root zone as soon as possible after application. Do not apply more than once per year. Do not apply within 80 days of harvest.

Foliar Application

Chemical Control of Root and Crown Rot (Foliar Application Only)
Product Active Ingredient Rate PHI* Comments

Aliette WDG

80% fosetyl-Al 5.6 kg/ha (2.2 kg/acre)   1
  • Group U
  • Use 300 to 1000 L/ha (120 to 400 L/acre) of water.
  • Apply first spray in late spring when there is at least 7 cm of new growth and continue on a 14 to 21 day interval.
  • Do not apply more than 4 times per year.

Confine Extra

53% mono and di-potassium salts of phosphorous acid 6.0 L/ha (2.4 L/acre) 1
  • Group 33
  • Use enough water to provide coverage.
  • Begin sprays when conditions are favourable for disease and continue on a 7 to 21 day interval.
  • Do not apply more than twice in succession. Alternate with fungicides from other chemical groups.
  • Do not apply more than 5 times per year.

Phostrol

53.6% mono- and dibasic sodium, potassium and ammonium phosphites 2.9 to 5.8 L/ha (1.1 to 2.3 L/acre) 0
  • Group 33
  • Use a minimum of 400 L/ha of water (160 L/acre). 
  • Begin sprays at the pink bud stage and continue on a 14 day interval.  
  • Do not apply more than 4 times per season.
  • Phostrol may cause crop injury in the form of brown spots and marginal leaf necrosis. 
  • Can be applied up until the day of harvest.  

*PHI = Pre-harvest interval (days)