Pictures of winter moth caterpillars

If you have a magnifying glass (10x is good) and you want to look for winter moth caterpillars, attached are a couple of pictures to help. Caterpillars are inside buds now, so to see winter moths, buds need to be peeled open. If a bud has caterpillars it is easier to find frass (insect poop) than caterpillars. Frass looks like small flecks of brown-black pepper in blueberry buds. In apples the frass can be reddish-brown to black.

At URI’s East Farm we sprayed March 30 for winter moth. We did not get very good control – though we don’t know how many caterpillars would be there if we didn’t spray. I think our poor control is due to winter moths hatching over a long period due to cool weather once eggs started hatching around March 27. Rain and snow washed off insecticide and the insecticide didn’t last through the entire time eggs were hatching.

We intend to spray apple trees and blueberries this coming week once fruit buds are at the tight cluster bud stage. Attached are pictures of apple and blueberry tight cluster.

blueberry bud
Blueberry bud 3.16.16

blueberry bud peeled open see frass and wm
Winter moth caterpillar and frass

apple bud

Apple bud at half inch green.

apple bud with frass and wm

Peeled apple bud with caterpillar and frass inside.

apple tight cluster
Apple tight cluster bud stage.

Blueberry tight cluster bud stage.