Tent caterpillars in cherry and crabapple trees
Tent caterpillars leave the tent to feed, so Btk sprayed on the leaves around the tent does reach them. Contact sprays aimed at the tent itself do not. The window is short. The caterpillars hatch in March in Kentucky and feed for only four to six weeks, and the University of Kentucky warns that insecticides are generally ineffective against mature larvae. Spray when the tents are new and the caterpillars small. A tent you can reach is simpler to pull out by hand. The Monterey label says Btk does not harm honeybees or ladybirds when used as directed, but it kills any caterpillar that eats treated leaves, butterflies included.
At a glance
- Damage
- Dense silk tents in branch forks in spring; leaves stripped around them
- Type
- Chewing
- Settings
- Garden, Field
- Threshold
- See profile
- Ally
- Bacillus thuringiensis kurstaki
- Rate
- Label rate — 4 tsp per gallon of water on the Thuricide and Monterey B.t. shade-tree and ornamental directions
How to confirm it
A dense white silk tent in the fork of a branch in early spring, with black caterpillars that have a white stripe down the back and blue spots along the sides. They leave the tent to feed. A loose web over the tip of a branch in late summer is fall webworm.
Identification, lifecycle, degree days and every control option are on the full Eastern tent caterpillar profile. Not sure it is this pest? Answer four questions about the damage.