Q: Little black bugs are eating the leaves off my corkscrew willow. What can I use to get rid of them?
A: Willow leaf beetles are having a feast at your expense!
They do great damage to the leaves but rarely kill a willow tree.
Adults are oval and have a greenish-blue metallic color. They usually appear in mid-May and are present off and on throughout the summer. Eggs that are laid in early June result in a population explosion a few weeks later.
Any insecticide labeled for outdoor use will kill adults and larvae. Look for products containing permethrin, bifenthrin, chlorpyrifos or pyrethrin.
Spinosad (Captain Jack’s Dead Bug Brew, etc) or carbaryl (Sevin) are also registered for use on leaf beetles. Spinosad is less toxic; carbaryl is more likely to adversely affect populations of natural enemies or pollinators. Spray when the insects are first seen and repeat in mid-July.