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Shelterbelt Centre Pest Leaflets
Poplar Budgall Mite
Hosts: Poplar
Appearance and Life History: The poplar budgall mite is about 0.2 mm and
is visible only through a microscope. All life stages overwinter within the galls. Mites are active
within the galls from April to October, completing a generation every 2 to 3 weeks, which results
in 8 or more generations per year. From May to August, some of the mites migrate to new,
unfolding leaves, where they begin feeding by sucking the plant sap.
Damage: During feeding, the mites inject a substance that causes a woody,
cauliflower-like gall to form. The mites are protected from predators and insecticides while
inside the gall. Newly formed galls are soft and green, but later in the summer become hard and
brick red. Galls may grow to 3-4 cm in diameter. Galls tend to be more abundant on the lower
branches. Infested branches are stunted, crooked, and have sparse foliage. Several years of
attack result in branch dieback therefore reducing the aesthetic and shelter value of the tree.
Galls can persist on the tree for 5 years or more. Infested trees become stressed and more
susceptible to secondary insects and diseases.
Control: No pesticides are currently registered for control of this mite.
Annual pruning and burning of galls will reduce infestations on individual trees but this is not
practical for plantations. Pruning should be done in the fall when the trees are dormant and the
mites are in the galls. Planting resistant clones is the best long term solution. Hybrid poplars
such as 'Walker', 'Assiniboine', and 'Manitou' are resistant to poplar budgall mite whereas
'Northwest' is very susceptible. 'Assiniboine', and 'Manitou' have the added benefit of being
male clones and therefore do not produce seed fluff.
For more information contact:
PFRA Shelterbelt Centre
Indian Head, Sask. S0G 2K0
Phone: (306) 695-2284 or Fax: (306) 695-2568
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