We have all fought the squash bug and lost the battle. This bug is the most serious enemy of our growing successful squash and pumpkin in the USA. The squash bug is only found from Canada to South America. Both adults and nymphs damage plants by sucking juices out of the leaves. The leaves then lose nutrients and water, become speckled, then yellow, then brown, and finally, the plant totally wilts. The squash bug also injects a toxin that expedites the plant's withering and death.
The squash bug has an ongoing life cycle. The adults we failed to eliminate last season will pass the winter under whatever shelter they can find - leaves, boards, stones, or debris. They will re-emerge as soon as the weather warms up (yes, just about the time those vulnerable baby squash plants are emerging). The adults mate soon after re-emerging and begin laying eggs in groups of a dozen or more. These eggs hatch in 10-14 days, and it only takes these new nymphs 4-6 weeks to reach maturity. So, all stages can be observed simultaneously throughout the season. How in the world do we control these multiplying monsters?
Let's just say that planning for control begins way before you plant the first seed. The very first line of defense includes several Systemic Strategies. Sanitation is a key measure. If adults over-winter under debris, get rid of all those hiding places. Next, plan to plant this year's crop where no squash or pumpkin grew last year; rotate your crops. While the bugs are quite capable of traveling, rotating and planting a little later will delay a bug population build-up. Companion planting is also worth a try, using repellent plants that deter the squash bug. They include catnip, tansy, radishes, nasturtiums, marigolds, bee balm and mint.
The second line of defense is Mechanical and Physical Strategies. The use of tightly secured barriers, such as floating row covers physically exclude the pests and prevent them from reaching the squash plants in large numbers. The covers can stay on until just before the female flowers appear. This is not labor intensive, and starts you out ahead of the war games. Another physical strategy is the use of kaolin clay products. Sprayed on the plants regularly at least every two weeks it forms a light-colored protective coating believed to deter the squash bug. Last season, I gave it a try. I sprayed half of my squash crop (both summer and winter) with kaolin and left the other half unsprayed. The results were measured daily by inspecting all leaves and counting (and removing) the number of squash bugs found in each area. While the method is definitely labor intensive (mixing and spraying every two weeks to cover new growth), I found 2/3 less squash bugs inhabiting the Kaolin covered plants. However, if I hadn't found and removed them by vigilant inspections, how much would they have multiplied?
The third line of defense is the Material Strategy. This includes biologicals and botanicals, such as sabodella, insecticide soaps and neem oil. Success with these is most effective on the nymphs. Once the adult bug emerges, this line of defense is not very effective.
Let me add my own suggestion to what all the experts have suggested: Vigilance. Checking under all the leaves each day will reward you with finding and removing the first line of adults, busily mating. Get rid of these, and their life's production cycle is interrupted,. With all these defense options to be tried, I wish you a great squash growing season!
FAQs
Keep your gardens clean of all old cucurbit vines and crop or leaf debris. With winter hiding places removed, squash bugs rarely survive the cold, so it cuts down on cucurbit invasions the next season. Tilling the soil well after harvest also goes a long way toward eliminating these pests.
Does anything repel squash bugs? ›
Companion planting is also worth a try, using repellent plants that deter the squash bug. They include catnip, tansy, radishes, nasturtiums, marigolds, bee balm and mint. The second line of defense is Mechanical and Physical Strategies.
Do coffee grounds keep squash bugs away? ›
The two best DIY sprays to use against squash bugs are a homemade soap spray or a coffee ground spray. You can spray these under your plant leaves twice a week to help repel squash bugs (just remember to re-spray if it rains).
What is the best insecticide for squash bugs? ›
The most effective products for adults were cyhalothrin (Spectracide Triazicide) and cyfluthrin (Tomato and Vegetable Insect Killer). It is especially critical to reduce the overwintering population of squash bugs by working the soil and/or removing foliage and fruit immediately after harvest.
How do farmers control squash bugs? ›
The best method for control is prevention through sanitation. Remove old cucurbit plants after harvest. Keep the garden free from rubbish and debris that can provide overwintering sites for squash bugs. At the end of the gardening season, compost all vegetation or thoroughly till it under.
Will squash bugs come back every year? ›
It is very likely that these bugs will come back every year in a shared setting like a community garden. If you grow squash family plants, start checking them for these bugs and eggs early in the spring. Eggs hatch about every 10 days. Check plants at least once a week for these insects in all stages of life.
Does vinegar repel squash bugs? ›
There is no evidence that vinegar kills squash bugs. Picking them off by hand and destroying them is the most eco-friendly method to quash an infestation.
What are the natural predators of squash bugs? ›
Natural enemies of squash bugs include several species of parasitic wasps and the tachinid (parasitic) fly Trichopoda pennipes, which is squash bug-specific. Although there are predators of squash bugs, predation tends to be low because noxious odors that repel predators are released when squash bugs are attacked.
Will Sevin dust keep squash bugs away? ›
Treat squash during evening hours when insect pollinators are less active, and avoid treating open blooms. GardenTech brand offers highly effective options that kill squash bugs and help protect your harvest: Sevin Insect Killer Dust Ready to Use starts killing squash bugs immediately upon contact.
Do marigolds keep squash bugs away? ›
Flowers like Nasturtiums and Marigolds help to benefit summer squash by a few different ways! They help to repel aphids and beetles away from tomatoes by acting as a trap. They can also be effective against repelling the squash bug and squash vine borer.
You may want to experiment with different companion crops until you find the perfect combination to fit your personal tastes and growing conditions. Avoid planting zucchini and summer squash with all other vining plants which include cucumbers and sweet potatoes as well as pumpkins, winter squashes, and melons.
What eats squash bugs? ›
Natural enemies of squash bugs include several species of parasitic wasps and the tachinid (parasitic) fly Trichopoda pennipes, which is squash bug-specific. Although there are predators of squash bugs, predation tends to be low because noxious odors that repel predators are released when squash bugs are attacked.
How long does squash bug season last? ›
Squash bugs are commonly found in groups on the leaves, stems, and fruit of cucurbits (Figure 1). When disturbed, they produce a foul scent and scurry away quickly. Peak squash bug activity occurs in late summer and continues until the first frost.
