Larch dwarf mistletoe
Last updated on January 30, 2025Arceuthobium laricis
Larch dwarf mistletoe is found in the southeastern region of B.C. in the range of the western larch where it causes reduced volume and wood quality among infected trees.
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Description
Aerial shoots of this species are 2 to 3 cm long, square in cross-section, purplish-green in colour, and are fan-like in arrangement where branched. Green berries containing sticky seeds are produced at the shoot tips. When mature, these seeds are forcibly ejected for distances of up to 15 m, to infect other susceptible trees.
Incidence of infection on immature trees and resulting damage appears comparable to that caused by dwarf mistletoe on lodgepole pine or hemlock.
Host tree species
Western larch is the preferred host. Lodgepole pine, western white pine, subalpine fir, grand fir, and interior spruce are occasionally attacked. Trees of all sizes and ages are susceptible.
Damage symptoms
Mortality and spike-top occur after prolonged infection. Infected branches and stems are usually very swollen. Witches’ brooms are dense and upright and have branches that are very swollen near the base.
Identification images
Further reading
Read more about larch dwarf mistletoe in the Field Guide to Forest Damage in B.C. (PDF, 6.5MB)