Bad Bugs

I found these caterpillars on one of my fruit trees this morning. I scooped them into a small jar so that I could identify them. They are called Redhumped Caterpillars (Schizura concinna). They attack deciduous fruit trees, especially plums, prunes, and walnuts. And, it was my plum tree that they attacked. You can see what type of damage they did, which is typical of these pests. Usually, they go after a single branch near the top of the tree and defoliate it. Young trees can be seriously damaged, but mature trees can tolerate substantial leaf loss without a problem.

The easiest way to get rid of these caterpillars is to just clip off the leaves they are feeding on and drop them into soapy water. There are many natural enemies of these caterpillars, including parasitic wasps. The wasps lay an egg in the caterpillar, where it hatches and feeds on the caterpillar's insides. My thinking is that by the time the wasp larvae kills the caterpillar, the tree's damage is already done. So, I just got rid of them the easy way--into the soapy water they went!