It’s like something out a horror movie…thousands of gray six-legged creatures pour out from under a leaf ready to devour. Meanwhile, deep inside the stem a fat, greasy sluggish creature eats the victim from the inside out. But this is no film, this is your garden. And these monsters are eating your squash.
Earlier this summer my squash plants were kicking out dozens of gorgeous zukes, patty-pans and yellow summer squash. Also a gorgeous albeit misplaced pumpkin plant was crawling over my front lawn, covered in blossoms and little baby pumpkins.
Meanwhile, a spaghetti -squash plant was climbing over my white picket fence, dripping with large ovoid fruits. Now the zucchini plants are turning brown, the tiny zukes are shriveling, the flowers dropping off. The pumpkin leaves are yellowed and the pumpkins themselves, once on their way to impressive jack-o-lantern size, are now stunted and shriveled while the spaghetti-squash vines have already dried up and blown away. Another scene from THE GARDEN OF HORROR? Sort of.
While I, their protector was otherwise engaged–the most hideous monsters were munching on my squash: the dreaded squash borer (caterpillar/moth) and the ubiquitous and rapidly-multiplying squash bug (‘beetle’).
But having identified the enemy is only half the battle–but how do you fight them?
The borer attack actually begins in late Spring, when a moth lays her eggs at the base of your squash plants. Each female lays about 200 eggs, but one at a time rather than in clusters, making the tiny eggs almost impossible to find. They hatch in a few weeks, and the evil little caterpillars that emerge quickly tunnel into the hollow plant stems where they feed, hidden from view for a month or so and then drop down into the soil to pupate. In our area, these new moths will then emerge as adults the following Spring.
One way to avoid the adult moth—which looks like a little red-bellied wasp—is to cover your squash plants with a floating cover which allow water, light and air through, but prevent bugs of all kinds. If you go this route, make sure you plant where squash didn’t grow the previous year (or the moth may emerge inside the row covers—eeek!) and either grow self-pollinating varieties or lift the covers and pollinate the flowers yourself with a little paintbrush as bees won’t be able to get through. In our area, you can remove the covers entirely by the Fourth of July; all the egg-laying action will already be over.
Another prevention is to grow your squash out in the open and use vigilance to get the eggs. You may not be able to see them, but spraying the vine weekly with insecticidal soap (for a homemade recipe click here) will smother them nonetheless. Once the season is underway, carefully inspect each vine once a week; don’t wait for wilting! If you see a hole near the soil line and that distinctive greenish bug poop that the borers push back out of their comfy new home, slit the vine vertically and find the caterpillar inside. Once you have destroyed the enemy you should then cover the damaged vine with compost-rich soil.
If this doesn’t work, in our area you can replant with new squash plants any time after mid-July; it will be too late for the new borers to do their evil work.
The problem with squash bugs is by the time you notice them often they are feeding on your squash in huge multitudes, so again, vigilance is key. Give your squash plants a regular ‘check-up’ early in the season; if you notice patches of tiny red bumps these are the eggs so remove the infected leaves and bag them. If you miss out on that stage you may notice masses of tiny black squirmers or their slightly older little white cousins. At this stage it is still possible to kill off the li’l buggers with repeated sprays of insecticidal soap. But be careful to spray only in the cool of morning or early evening and not during the heat of the day or you will damage the delicate squash foliage. If in doubt, always ‘test’ an area of the foliage before spraying. I find that the gray-brown mature squash bugs are not so readily dispatched with soap but if you kill off enough of the young ones the population will soon be diminished.
There is no need to buy insecticidal soaps as it is easy to make your own. For a sure-fire recipe please click here. I hope this helps you keep your squash plants healthy and your squash growing--it’ll be up to you to deal with that overlooked zucchini that is now the size of a baseball bat!