Question
I think I have identified this caterpillar as a hackberry leaf slug, but it only said to use a leaf feeding insecticide. Please tell me what I need to use or do and will this keep them from coming back?

Answer
You can spray the foliage with an insecticide but will need to be able to reach all the foliage in order to kill all the caterpillars. Killing them will drastically reduce the population so the numbers may be small next year or none at all. Here is a list of insecticides for caterpillars.

Caterpillars (cankerworms, Eastern tent, euonymus, European pine shoot moth, fall webworm, gypsy moth, spiny elm, walnut, white-market tussock moth)

?       Bacillus thuringiensis (Thuricide, Dipel)

?       Carbaryl (Sevin)

?       Cyfluthrin (Bayer Power Force Multi-Insect Killer)

?       Dimethoate (Cygon, Hi-Yield Cygon)

?       Esfenvalerate (Ortho Bug-B-Gone Multipurpose Spray)

?       Imidacloprid (Bayer Advanced Tree %26 Shrub Insect Control)

?       Insecticidal soap (Safer抯, Concern)

?       Permethrin (several products)

?      Pyrethrin (several products)



Usually the slug type caterpillars are not doing much damage to the tree by eating the leaves and are not controlled. But the above will work.