Squash plants are thriving in this summer heat, and for many gardeners, that means the harvest is just beginning. But before you start planning your next zucchini bread or squash casserole, you might need to consider who else is eyeing your crop—and I’m not just talking about your neighbors.
Insects are starting to move in, and if you’re not careful, they could get the first—and biggest—bite. Luckily, with a little vigilance and timely action, you can stay one step ahead.
Know Your Enemy
When it comes to pest control, the first step is always identification. Applying the wrong treatment wastes time and money—and won’t solve the problem. Fungicides won’t stop insects, and insecticides won’t touch fungi. Take a close look at your plants, do a little research, or bring a sample to your local extension office for help identifying the issue before you reach for the sprayer.
Meet the Squash Vine Borer One of the most destructive squash pests is the squash vine borer. This stealthy invader lays its eggs on the base of squash, pumpkin, and gourd plants.
Once hatched, the larvae burrow into the stem and feed from the inside out. Look for sawdustlike frass (insect droppings) near an entry hole which is often the first visible clue.
As the larvae feed, the plant may wilt suddenly and begin to rot at the base. Severe infestations can take out the whole plant. After feeding, the larvae drop into the soil to pupate and overwinter, ready to start the cycle again next year.
How to Fight Back
Control starts with prevention. Clean up plant debris, rotate crops, and inspect stems near the soil for eggs. If you catch the larvae early, you can carefully slit the stem to remove them or insert a wire into the entry hole to kill them. Yes, it’s a bit invasive—but it may save your plant.
For chemical control, use insecticides labeled for vegetables, applied when eggs are being laid—typically when vines begin to run. Follow label directions closely, and plan on reapplying every 7–10 days for 3–5 weeks.
The Squash Bug Invasion Right behind the vine borer is another heavy-hitter: the squash bug. Adults are brownishblack, shield-shaped, and tend to cluster on the underside of leaves and around fruits.
Nymphs are smaller, gray, and teardrop-shaped with black legs. These bugs overwinter in plant debris and emerge in the growing season to lay eggs—small, oval, and reddish-yellow—on the undersides of leaves where veins form a V. Squash bugs are more damaging than they look. While feeding, they inject toxins that can cause Anasa wilt, a condition that causes plants to collapse and die. Again, early detection is key. Crush eggs when you find them and apply insecticides when nymphs are active—not once they’ve matured into adults. Reapplication will be needed regularly throughout the season.
Bottom Line: Squash season is here, and so are the pests.
With a bit of observation and a timely response, you can protect your plants and enjoy a bountiful harvest… without sharing too much with the bugs.
Elizabeth Exstrom is the Horticulture Extension Educator with Nebraska Extension in Hall County. For more information contact Elizabeth at elizabeth. exstrom@unl.edu, her blog at http://huskerhort.com/, or HuskerHort on Facebook and Twitter.