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Trees/oak tree caterpillars


We live at Belair, close to Lake Winneipeg.  For the past two weeks our many oak trees have been infested with tent caterpillars?  Not sure if thats what they are.  They are grey green in colour, about 1 1/2 inches.  They have stripped many of the oak trees and are working on the rest.  The sound of their poop falling is like rain.  Have you had any other reports, and are these indeed tent caterpillars?


These are Forest Tent caterpillars. These caterpillars do not make tents but will eat the foliage. The good news is they have only one life cycle per year so they will live about 2-4 weeks and pupate. hatch into moths and lay eggs. They usually are around in June July. not sure why they are late this year. In a homeowner situation you can spray the tree trunk and this will kill the caterpillars as they crawl down the trunk. BUT the bad news in Canada the insecticides are limited that you can use. In the US we would use: insecticides that provide good tent caterpillar control include those containing permethrin, lambda- cyhalothrin, cyfluthrin, bifenthrin, fluvalinate, esfenvalerate, carbaryl, acephate or malathion.

The good news is they will not kill the tree and next year it will leaf out. In fact you will see some new leaves this year if the cold weather does not come too early.


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Jim Hyland


I am an expert in Forestry, Forest Entomology, Forest Pest Control, and Forest Health. Extensive knowledge in Identification of insects and diseases of trees. Expert on Bark beetles and other insects that attack forests. Also a Registrated Forester with extensive knowledge in the management and care of forests.


34 years as State Pest Management Chief in a Southern state. Extensive knowledge in Forestry.

BS with major in Forest Management and Entomology
Registered Forester
Certified Pesticide Appicator

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