striped lady bug

Asked May 6, 2016, 5:15 PM EDT

This odd bunch of striped lady bugs seem to be eating plants. Should they be considered a pest? The plant is being eaten to a skeleton but we did find one aphid too on the same plant.

Multnomah County Oregon

1 Response

The insects are not lady beetles. They are coreopsis beetles, Caligrapha californica. There’s very little information about these beetles but, when they are present in a garden, they commonly strip all the leaves from coreopsis plants. In our region, their populations seem to peak every five years or so.

Some people manage the beetles by bagging the remains of the plant, along with the feeding beetles still in place and, then, cut the plant off at ground level and discard the tightly secured mess in the trash.

The insects in your image are adults. More than likely you can also find some of the larvae (youngsters). They’re small and all black. Both the adults and larvae eat the leaves. See http://growingthehomegarden.com/2009/05/leaf-beetle-larvae-calligrapha.html.

You might also try to flick the insects into soapy water. This is likely to work best if you act early in the day while the critters are still sluggish from the cold.

More images at http://oregonstate.edu/dept/nurspest/Calligrapha%20californica.html. Unfortunately, some of the links here are broken.

This site suggests drenching the plant with insecticidal soap. (I suspect that will be more effective against the larvae than the adults.) They also say “The solution must be rinsed off two to three hours after each application, then reapplied in four to seven days.” http://www.ehow.com/how_5692469_care-tickseed-flowers.html