killing catalpha sphinx worms

Asked August 14, 2019, 1:05 PM EDT

I have a catalpha(cigar ) tree and this is the second year we have had sphinx caterpillar worms on it. It is a very large tree. How can I kill these worms???

Jefferson County Ohio

1 Response

Catalpa sphinx worms are the caterpillar stage of the Catalpa sphinx moth. These caterpillars feed on Catalpa leaves and can sometimes completely defoliate a tree. Trees will typically leaf out again, although repeated cycles of defoliation can cause die back and unsightly damage. Chemical treatment is often not recommended as natural predators often keep this pest in an acceptable balance. However, if chemical treatment is desired, there are some formulations of carbaryl, malathion or acephate that can be used. Treatment should be done when the caterpillars are small. Hiring a certified arborist to treat the tree might be your best course of action. In addition, in the Fall, clean up any debris (or till the area) under the tree to reduce the number of overwintering pupae. If you see any caterpillars with whitish eggs on them don't destroy these. There is a small native wasp that preys on the caterpillars by laying its eggs on them. The wasps then hatch and feed on the "worms". It's also interesting to note that Catalpa sphinx worms are prized as fishing bait. Here is a link to more information about the Catalpa sphinx:
Remember to read and follow all label directions when electing any chemical control.