Winter moth and apple update

Just a quick update on winter moth. It’s a good time to check your blueberries and see whether or not you find winter moth caterpillars. Look on the top of blueberry buds for insect frass (droppings). Consider spraying Bt or a spinosad product (Captain Jack’s Deadbug Brew, Delegate, or Conserve) if you find much damage. Don’t use spinosad if buds are close to opening. Bt is safe to use on open flowers since it does not harm bees.
blueberry bud and frass       blueberry bud with caterpillar
Winter moth frass on blueberry bud.   Blueberry bud pulled apart and see caterpillar.

I haven’t done much scouting around the state, but I have not seen any areas with a high population of winter moth caterpillars. Caterpillars are still small and I haven’t been many places. If you see areas with a lot of damage please let me know.


Just a quick update – At this time no fire blight infection is predicted over the weekend according to Orchard Radar. Check out the two fire blight models on Orchard Radar through bloom. Select either the Greenville or Newport County site, which ever is closer to your orchard.

Greenville fireblight

Newport County fire blight

Check your apple leaves and buds for winter moth damage. It’s often easier to find frass than winter moth caterpillars. Most caterpillars I found today were inside stuck or folded leaves. See attached pictures. If you are finding much damage consider applying a Bt insecticide such as DiPel.
apple leaves with winter moth damage      apple leaves opened see winter moth
Damaged apple leaves from winter moth.        Apple leaves pulled apart and see small caterpillars.

The New England Tree Fruit Management Guide on-line version is available at