White Bugs on squash - not whiteflies

Asked August 7, 2015, 10:26 PM EDT

I have some very strange looking bugs on my squash pants (spaghetti, zucchini & yellow crookneck). They do not look like whiteflies, or squash bugs. They are tiny (about the size of a pencil tip), long-ish, white, have 2 what appear to be eyes (like black slits on top of the body) and they move more like a worm ... kind of centipede-like. My leaves are dying (yellowing with brown spots). I have tried the homemade mix of rubbing alcohol, water, and dawn dish soap & sprayed but it didn't do much.

Pierce County Washington

5 Responses

Have you seen any of these guys in your squash plants? They are a member of the Coccinellidae family--the ladybeetle family. The Mexican Bean Beetle (Epilachnavarivestis Mulsant) is slightly larger and more rounded looking than the familiar ladybeetle. Most of the beetles from this family are beneficial, but these will skeletonize the leaves of curcurbits (squash, cucumbers, melons, etc.). I'm not certain, but it looks like the immature larvae from this beetle. I'll try to verify it, but if you have seen the adult beetles on your plants, you have your answer. Here is more information about them: http://extension.entm.purdue.edu/publications/E-100.pdf

Here are some treatment options: http://insect.pnwhandbooks.org/vegetable/vegetable-pests/hosts-and-pests/bean-dry-mexican-bean-beetl...

Hi Alice
Thank you so much for your quick response. I actually have these other bugs (see attached) on the same the plant but definitely not as prevalent as the others. They look similar to the ladybeetle but more brownish. The larvae are very white whereas the Mexican beetle larvae looks yellow from the material you sent. And the have little black hairs whereas mine are ALL white.
I haven't had any skeletonization on any of my leaves. Just browning & yellowing. Also I haven't seen any eggs.
Marcie

Hi Alice
Thank you so much for your quick response. I actually have these other bugs (see attached) on the same the plant but definitely not as prevalent as the others. They look similar to the ladybeetle but more brownish. The larvae are very white whereas the Mexican beetle larvae looks yellow from the material you sent. And the have little black hairs whereas mine are ALL white.
I haven't had any skeletonization on any of my leaves. Just browning & yellowing. Also I haven't seen any eggs.
Marcie

Okay, then! You've got GOOD bugs there. That looks like the 20-spotted ladybeetle. It's a beneficial insect, especially the larvae! Aren't you the lucky one! This is a type of Ladybeetle that feeds on downy mildew, a common disease on squash plants. It's a perfect beneficial insect for your organic garden.It looks like the Psyllobora vigintimaculata, also known as the 20-spotted ladybeetle, or small ashy-gray ladybeetle. Here is a little more info about it: https://puyallup.wsu.edu/plantclinic/wp-content/uploads/sites/408/2015/02/PLS-34-Small-Ashy-Gray-Lad...

Thanks for sending me the images of the beetle! This is the 3rd time I've seen it this year.

Also, if you DO have powdery mildew, here's some information about it from WSU's Hortsense: http://hortsense.cahnrs.wsu.edu/Public/FactsheetWeb.aspx?ProblemId=219

Alice
Thank you so so much for the info. I feel much better now - although I feel kinda bad spraying those little guys! the powdery mildew did become a problem a few weeks back even though I'm using a soaker hose!
Have a great weekend!
Marcie