Birthing bugs

Asked June 13, 2019, 3:08 PM EDT

Found these lumps on a leaf and watched what transpired to be a birthing of a sorts...what are these?

Multnomah County Oregon insect identification

3 Responses

Hello from Ask an Expert - I'm working on the photos of the insect you want to identify. Could you tell me what plant/tree you found these on? It will help narrow down the field.


I don't know what the name of the plant is. The plant was not flowering, about 3 feet high with somewhat eliptical leaves.

Thank you for using Ask an Expert for help with identification of these insect larvae.

After consulting a university entomologist, it seems that the insect is in the beetle family (coleoptera). This is a large family of bugs, which includes many leaf beetles (chrysomelids)—pests of viburnum shrubs, alder trees, other ornamentals, and a number of vegetable crops. Though I cannot confirm it, this could be the cottonwood leaf beetle. Here is a US Forest Service publication on that insect:

The red galls may be evidence of an aphid infestation. As these insects feed, they cause the leaf tissue to enlarge and enclose the insects—protecting them from predators.

If you would like assistance controlling either of these insects, contact the Multnomah County Master Gardeners at 503-445-4608 (Monday through Friday-- 10:00 am to 2:00 pm).

Have a good gardening year,