Eriophyid Mites - Family Eriophydae

On Mountain Ash                   damage to leaves
Mountain Ash                                                            Maple


Three Stages of Infection                     Blister Mite on leaves
Boxelder                                                              Apple
Helen Atthowe, Missoula County Extension


TYPES
HOSTS
DESCRIPTION:
Aculops tetranothrix Willow Red or yellow pouch galls
Appleleaf Blister Apple and crabapple species Rusty blisters on leaves
Chokecherry Finger Gall Chokecherry Green/red galls on the upper surface of leaf
Eriophyes celtis Hackberry Witches' brooms
Eriophyes negundi Boxelder Cottony growth and pouch in leaves
Honeylocust Rust Honeylocusts Rusty colored leaves
Linden Fingergall Lindens Small finger galls on leaves
Pear Russet Pears Russetting discoloration of fruits
Pearleaf Blister Pears Rusty blisters on leaves
Phyllocoptes didelphis Aspen Velvety red or brown growth on leaves
Phytoptus sorbi Mountain Ash Yellow pouch galls in leaves
Plum Fingergall Wild plum Green finger galls on lower leaf surface
Poplar Budgall Poplars, Cottonwoods Distortion of buds
Triestacus spp. Pine Rosetted growth and stunted needles
Unknown Lilac Rusty colored leaves


CONTROLS: Eriophyid mites usually overwinter as eggs on their hosts. Treat with horticultural oil as the first buds break in the spring. Dormant bud oil sprays may not be particularly effective. If eriophyid mite feeding has been heavy (>50% of leaves damaged), you might consider a second horticultural oil or insecticidal soap application when the first leaves begin to expand. Most woody species in Missoula have shown no detrimental effects from heavy eriophyid mite infestation during a five year monitoring period.


Missoula County Extension Office; Missoula, Montana 59808 - Updated for 2006