Tent caterpillars in crabapple trees

(Question)

Tent caterpillars have taken up residence in my crabapple tree! What should I do? They are also in my neighbour’s yard.

(Answer)

First, you can destroy the tents and insects manually. In the early morning or late afternoon or on cool rainy days, when the caterpillars are at rest, you can cut the tents away and dispose of them in a sealed garbage bag.

You can also try using BT (bacillus thuriengiensis) a biological insecticide that is not harmful to the environment. It will only kill the caterpillars and is relatively safe for other creatures. BT must be ingested by the caterpillars to be effective. It is most effective in the early season when the caterpillars are young. Opening the tent prior to applying BT will help ensure that the caterpillars are exposed to the spray.

In the fall, remove the egg cases and cocoons by gently scraping them off the bark.

Even so, some eggs will survive, so next year, in early spring spray the tree with dormant oil, following the package directions.