Elytroderma needle cast

Elytroderma deformans

Elytroderma deformans is a unique needle cast fungus in B.C. that has the ability to spread from needles to shoot tissue and then re-infect new needles from shoot tissue the following year.

On this page

• Description
• Host
• Damage symptoms
• Management
• Identification images

Description

Elytroderma needle cast occurs throughout the range of ponderosa pine and lodgepole pine in B.C. Elytroderma needle cast infection can result in perennial infections that allow the fungus to survive during years of unfavourable weather conditions for spore infection. It causes large conspicuous brooms on ponderosa pine, but on lodgepole pine, it often goes unrecognized or is mistaken for lodgepole pine dwarf mistletoe.

Throughout most of the range of lodgepole pine, infections are restricted to the lower crown where they cause abnormal ring growth and large elongated knots. Lower infected branches often remain alive when uninfected branches above them are shaded out.

In the Cariboo IDF (Interior Douglas-Fir and SBPS (Sub-Boreal Pine-Spruce) biogeoclimatic zones, if the tree leader becomes infected the disease can remain in the upper crown for 40 years or more. These older infected trees have much reduced growth rates and shade out and serve as an infection source for lodgepole pine regeneration coming up below.

Only the current year’s foliage is infected, but needles don’t begin to show symptoms until the following year. Infected one year old needles turn red in the spring, gradually fade and then are cast. Conspicuous elongated fruiting bodies that form on the needles in mid-summer, help differentiate elytroderma from lophodermella needle cast, another common foliage disease of lodgepole pine. Repeated needle casting can result in branches that resemble lions tails (only tufts if current years needles are present at the ends of the branches). Infected needles often have stunted growth.

Host tree species

Ponderosa pine and lodgepole pine. All ages of trees are susceptible but new spore infections on lodgepole pine generally occur on younger trees within one or two meters of the ground.

Damage symptoms

Only the current year’s foliage is infected, but needles don’t begin to show symptoms until the following year. Infected one year old needles turn red in the spring, gradually fade and then are cast. Conspicuous elongated fruiting bodies that form on the needles in mid-summer, help differentiate elytroderma from lophodermella needle cast, another common foliage disease of lodgepole pine. Repeated needle casting can result in branches that resemble lions tails (only tufts if current years needles are present at eh ends of the branches). Infected needles often have stunted growth.

Management

A lodgepole pine progeny trial with a high incidence of elytroderma needle cast in the Chilcotin indicated that families from the colder SBPSxc and IDFdk4 were more susceptible to elytoderma needle cast than families from the warmer SBS and IDFdk3. The initial infection period of many mid rotation lodgepole pine stands in the Cariboo infected with elytroderma needle cast can be traced back to lophodermella needle cast outbreaks in the mid to late nineties. Younger lodgepole pine stands, that were established after this time, show lower rates of elytroderma needle cast infection. Because of the systemic nature of this disease, the Hawksworth rating system, where elytroderma needle cast infected branches are used in place of dwarf mistletoe infected branches, is well suited for rating elytroderma needle cast severity. Read a detailed land management handbook on elytroderma needle cast.

Land Management Handbook 74 Elytroderma needle cast on lodgepole pine in British Columbia Elytroderma needle cast on lodgepole pine in British Columbia

Identification images

Further reading 

Read more about elytroderma needle cast in the Field Guide to Forest Damage in B.C. (PDF, 6.5MB)