Cool weather is curbing plant and insect development. Winter moth caterpillars are still first and second instars – so very small caterpillars. It is a good time to scout your apple, pear, and blueberry buds for winter moth caterpillars and damage.

Over the last few days apples and blueberries were scouted in Portsmouth, Little Compton, Warren, and South Kingstown, RI and Franklin, MA. I found very few or no caterpillars in Little Compton, Warren and Franklin, but the orchard and blueberries in Portsmouth and South Kingstown had 10-20% of buds infested with winter moth, so an insecticide treatment was recommended. It’s pretty easy to see winter moth damage not if you use a magnifying glass, or have young eyes! Early next week should be a good time to spray a Bt insecticide. I see very few winter moth caterpillar in landscape trees and don’t think any insecticide is needed on landscape trees.

Fig 1, apple buds with winter moth frass

Fig 2, blueberry bud with winter moth frass