Question of the Week – Japanese Beetle

Which insect caused the feeding damage to this collard leaf?

While this chewing-type damage looks similar to caterpillar feeding damage, it was actually caused by a Japanese beetle. The hind end of the culprit is visible below.

Japanese beetles are active and easy to find right now, feeding on a range of plants from roses and hydrangeas to collards and sweet corn. However, since they typically have only one generation per year, this invasion won’t last much longer.

This week’s question serves as a reminder to scout carefully to ensure you know which pest is causing damage before selecting a treatment option. While the pictured damage closely resembles caterpillar damage, caterpillar insecticides (Bt, Coragen, Proclaim, Torac, etc.) won’t manage beetle pests. So, when damage appears, search until you find the culprit. If you can’t find it, it may be gone, in which case no further action is required.

This week’s question is from Justin Ballew, Extension Fruit and Vegetable Research Associate.