Squash Vine Borer and Downy Mildew
“Oh, what a pretty bug” was my initial thought when I found a squash vine borer (Melittia satyriniformis) resting on a catnip leaf earlier this week. It’s a moth-family insect I wasn’t familiar with and after reading about it, I felt rather sick. This is what finished off my melon plants last year. The borer deposits tiny, copper-colored eggs on the tops and undersides of squash, gourd, or melon leaves; or on the stems, the larvae crawl over to the vine base, chew into the vine, set up a cozy little home, and suck the life out of the plants. The leaves wilt and that’s the end. One day the plant looks great – the next day it’s dead. Disgusting.
I called the MSU Extension garden hotline and Sevin was suggested. After collecting many baby toads and placing them in the garden, I just can’t bring myself to applying it. Sevin is an effective, but nasty pesticide. It’s not natural or organic and I just can’t use it. Instead, I applied EndAll by Safer - an organic garden compliant formula of pyrethrin, potassium salts of fatty acids, and neem oil. Between the EndAll, vigilance, and placing a yellow bowl of water to attract and drown the borer adults, I am keeping my fingers crossed. I have only seen two borers and one is too many.
At the far end of the garden, I noticed the squash in the Three Sisters mounds didn’t look right. All of it has signs of downy mildew and once it’s visible, it could be the end of any hope for pumpkins, zucchini, summer squash, or butternut squash. It appears that if the borer doesn’t kill everything, the mildew might. Downy mildew is spread by airborne spores from a fungus-like organism and all the rain we have had likely fueled it. What is loud and clear in my reading is that I should not have planted my squash in the same place as last year. Ugh. There is still a slight chance that I have caught it early enough (no flowers yet) so I applied Garden Fungicide by Safer brand. It contains sulfur that kills the mildew on contact and prevents its spread.
In better news, the tomato plants are over five feet tall and loaded with blossoms, I’ve harvested more basil, the rest of the radishes and lettuce will be picked today if I can stand the heat, I have harvested and dried 35 bundles of catnip, and have just parts of the squash area left to weed. I have been weeding – a lot. Even though the rain has made the task of pulling easier, the volume is a bit much and I am in the garden almost every day trying to keep up.
After this oppressing heat passes, I’ll take a very close look at the squash, gourd, and melon plants to look for borer evidence. I may perform “surgery” by slicing any infected vines open, picking the larvae out with tweezers and killing ‘em, then covering the vine base with mulch.