Over the weekend, I noticed my squash and pumpkin vines were wilted. I assumed the stretch of days where it felt like 100 – 115 with the humidity was the culprit. Well, the heat wave passed and they were still wilted. I checked the soil yesterday thinking they weren’t getting enough water and noticed some strange looking yellow sawdusty, pus-y stuff on the roots.

I touched one of the roots to see what it was and the whole thing broke in half and it was filled with fat white larva. I screamed like a little girl, of course, because I touched the disgustingness with my bare hands.


After some searching, it turns out it’s squash vine borer. The squash vine borer is a moth with a red body and black wings that hatches from its cocoon in late June/early July. They lay eggs near squash, pumpkin, melon and cucumber plants. The eggs hatch about a week later and bore their way into the stems of the plants. The yellow sawdusty, pusy-y looking stuff is called frass and it must be the innards of the plants. The larva eat the inside of the stem and block the flow of water to the rest of the plant. After a month, they leave the plant and go into the soil until they turn into moths the next summer.
From my research online, the most effective way to control them is to prevent them from laying their eggs near the plants. In late June, you can put a yellow bowl or pan (they’re attracted to yellow) of water in the garden. Check frequently for the moths. When you see them, cover your plants with row covers, making sure they moths cannot get under them. Leave the row covers on for a couple of weeks. I’ll probably go this route next year and sprinkle diatomaceous earth on area around the roots for good measure.
If the larva get into the plant, you can slit up and down the stem and kill the larva as you go. Then you have to heap soil over the cut portions and keep it moist. I tried this but the larva were a good foot up the stem and there’s no way I could mound soil over it because I have the plants trellised. I’m so sad because I have some good size fruit on the plants.

There are chemical options but I didn’t bother looking closely at them because I don’t want to use chemicals in the garden.
One of the most important things is to destroy the plants with the larvae to lessen the impact the following year.