I have been getting a lot of calls about caterpillars that are migrating into people’s yards, gardens, and sometimes their houses. These hairy caterpillars have been taking over vegetable and flower gardens and quickly eating many of the plants’ leaves. Although not a yearly occurrence, these caterpillars migrate every year looking for a place to overwinter as larvae. 

Eristigme acrea, or woolybear caterpillars, as they are commonly called, are the larval form of the tiger moth and are typically are found in soybeans and other legumes during the summer months. There are two generations of caterpillars each year (May and August). The second generation is the one you have noticed now as they are crossing the roads, usually in great haste as if they have someplace special to go. In fact they are only scurrying to find a sheltered location under dead plant debris, etc. where they will spend the winter as a larva. In the spring they will feed briefly before changing into a cocoon and eventually a moth. Eggs laid by the female moths start the cycle over again. In most years, the fuzzy larvae are harmless to a homeowner’s plants, and they go on their way to overwinter without much fuss. Unfortunately, this year they are feeding along the way to their winter homes. This is unusual, but can happen. It is not recommended that you treat for them at this time, since most plants are in a state of decline with the fall season upon us, and they should be moving on soon.

Alicia Boor is the Agriculture and Natural Resources agent for Cottonwood District (which includes Barton and Ellis counties) for K-State Research and Extension. Contact her by email at aboor@ksu.edu or call 620-793-1910.