Both summer squash varieties (also called zucchini) and winter squash types are a regular find in home vegetable gardens. They are productive and easy to grow. However, squash certainly face their share of garden pests, the most common of which is the squash bug. If you’ve ever faced a squash bug infestation, you know how challenging these pests are. This article examines how to get rid of squash bugs effectively and without the use of synthetic chemical pesticides.
What are squash bugs?
Squash bugs (Anasa tristis) are a member of the stink bug family. If you disturb or injure them, they emit a foul odor. Like other stink bugs, they feed on plants by piercing plant tissue with their needle-like mouthpart and sucking out the plant sap. Squash bugs are found all across North America and are native to the continent. They feed on all members of the cucurbit family but tend to prefer summer and winter squash, as well as pumpkin vines and gourds. They are not as problematic on cucumbers and watermelons.
Squash bugs overwinter under plant debris as adults. They emerge in the mid to late spring and seek out their host plants. Adult squash bugs are ½ to ¾ of an inch long, dark gray to dark brown, and shaped like an elongated shield. Soon after emerging, they start to feed and mate. Females lay eggs on squash plants, typically on the undersides of leaves. Squash bug eggs are bronze-colored and football-shaped and are always laid in clusters.
In 10 to 14 days, the eggs hatch into tiny, light gray, wingless nymphs that typically congregate on the underside of a leaf or along a plant stem. Their lifecycle passes through 5 different stages before they mature into adult squash bugs and repeat the process again. Both adult squash bugs and squash bug nymphs feed on and damage plants. In cooler growing areas there is one generation per year. But in warmer growing zones (or even during warmer years), there can be multiple generations or even a year-round overlap of generations. This is why learning how to get rid of squash bugs is so important.
What does squash bug damage look like?
Squash bug damage is distinctive. It appears as mottled yellow spots on the leaves that eventually turn brown. Severe infestations result in dark brown leaves that turn crispy and dry.
Squash bugs also feed on the developing fruits of squash plants, typically at the stem end. On fruits, they cause sunken, pale areas that eventually lead to fruit rot.
The good news is that, unlike cucumber beetles, squash bugs do not spread bacterial wilt. However, their feeding does damage the vascular tissue of the plant, which in severe cases, can lead to sudden plant wilting and even plant death.
Why learning how to get rid of squash bugs is important
While plants tolerate small to moderate amounts of squash bug damage and still produce a good crop, controlling squash bugs in the current growing season means you’ll have fewer of them the next season. If the population gets out of control and there are lots of adults to overwinter in your garden, they are more difficult to manage at the start of the following season. In other words, the more squash bugs overwinter, the more eggs are laid the following spring.
When it comes to managing any pest in the vegetable garden, prevention is always key. If you had squash bugs in the garden, clean out infested plant debris at the end of the growing season so they have fewer places to hide. Do not use loose mulch products, like straw or hay, because squash bugs like to take shelter in them. In addition to these tips, here are 8 other methods to use to successfully get rid of squash bugs in your veggie plot.
How to get rid of squash bugs: 8 methods
As a horticulturist and former organic market farmer, I’ve tried many strategies when it comes to figuring out how to get rid of squash bugs. Some have been more successful than others, but none of them involved synthetic chemical insecticides, whether in spray form or powder. There’s no need for them, really. Squash bugs are unharmed by many pesticides because of the way they feed combined with their tough exoskeleton, so spraying these products may prove more dangerous to you than it does to the squash bugs. If you want to know how to get rid of squash bugs safely and organically, here are 8 strategies to use.
1. Grow resistant varieties
While no squash variety is fully resistant to squash bugs, some are less attractive to the insects and more tolerant of their damage. By growing squash bug-resistant varieties, you’re hedging your bets and limiting your losses. Here are three squash types that are more resistant to squash bugs:
- Royal acorn
- Round zucchini varieties, like ‘Eight Ball’
On the other hand, there are also a few varieties that squash bugs adore. If you don’t want to have to worry about how to get rid of squash bugs, don’t grow blue hubbard squash or pumpkins as they are favorites. However, in the next section, I’ll introduce a clever way you can use blue hubbard squash to trick and trap squash bugs.
2. How to get rid of squash bugs using companion planting
There are three ways to use companion plants to control squash bugs.
- Combine zucchini with nasturtiums. On an Iowa State research farm, researchers noted a reduction in squash bugs and squash bug damage when summer squash was interplanted with a companion plant of nasturtiums.
- Another study found that growing tansy with winter squash plants resulted in reduced squash bug egg laying.
- Grow your squash in a mixture of plants, rather than in long rows. Big areas of a single crop are like a welcome mat to pests, including squash bugs. Mixing your squash plants in happy harmony with lots of other flowering plants and vegetables will make it harder for pests to home in on them.
A fourth way involves using a trap crop. As mentioned, squash bugs much prefer blue hubbard squash to other varieties. Plant blue hubbard squash as a sacrificial trap crop to lure the pests away from your desired crop. Site the hubbard squash several feet away from the variety you want to harvest and plant it a few weeks earlier. You can then destroy the squash bugs found on your hubbard squash, suck them up with an old vacuum cleaner, or just let them do their thing. Learn more about this technique in this article on companion planting strategies for zucchini.
4. Attract beneficial insects to control squash bugs
You might be surprised to learn that beneficial insects play an important role in figuring out how to get rid of squash bugs. There are several “good” garden bugs that feed on squash bugs and by encouraging them to come to your garden, you’ll have a form of natural pest control. Here are the two primary beneficial insects that help manage squash bugs and some plants to include in your garden to help support them.
- Spiders. While web-spinning spiders aren’t big predators of squash bugs, hunting (or cursorial) spiders are. Though they aren’t technically insects (they’re arachnids), they do fit into the beneficial insect category. These hunting spiders crawl around on the soil and up into plants to eat their prey, almost exclusively at night. Encourage them by planting a lot of flowering plants and low-growing herbs in and around your squash plants.
- Tachinid flies. This large group of parasitoidal flies use squash bugs (and many other insects) to house and feed their developing young. The female fly lays an egg on the back of the squash bug and the little larva burrows into the squash bug and… well… you can guess what happens from there. There are thousands of species of tachinid flies, but not all of them use squash bugs as a host. Others use various caterpillars, other true bugs, and even beetles. Plant dill, calendula, marigolds, mint, fennel, catnip, and other plants with small flowers in the vegetable garden to provide the adult tachinid flies with plenty of nectar.
5. Use a physical barrier
Row covers, fine screening, insect netting, or even tulle fabric are useful tools in controlling squash bugs. Cover plants when they are young and leave the cover in place until the plants come into flower. You’ll have to remove it at that time to allow access to pollinators. But by that time, the squash bugs have gone elsewhere, and the plants are strong and healthy. Growing squash under mini hoop tunnels is a great tool for limiting squash bugs. Check out our online course called How to Build and Use Mini Hoop Tunnels in the Vegetable Garden to learn more about how to do this.
6. How to get rid of squash bugs with duct tape
When it comes to learning how to get rid of squash bugs, using duct tape is my favorite trick of all. Wrap a piece of duct tape, sticky side out, around your hand. Then search your squash plants for the clusters of bronze-colored eggs. Tap the duct tape against the egg cluster to collect them. Use it to collect young nymphs and even adult squash bugs, too. Catching the females early in the spring, before they lay eggs, is a great strategy if you can regularly search the plants.
When you’re done, discard the tape in the trash bin. Do this every 7 to 10 days to always stay ahead of the hatch cycle.
7. How to handpick squash bugs
Handpicking adult squash bugs and dropping or knocking them into a bucket of soapy water is yet another way to get rid of squash bugs. I’m also quite keen on using my pruning shears to cut them in half when I spot them in the garden. They’re kind of big and messy to squish between your thumb and forefinger (plus the stink they emit tends to linger on your hands for quite a while), so I opt to use my pruners instead. I know, it seems kind of gruesome, but it’s definitely a quick death.
8. Using squash bug traps in the garden
There are a few possible ways to trap squash bugs to get rid of them, especially when it is a large infestation.
- Lay wooden boards or squares of cardboard around the base of squash plants in the afternoon. Often squash bugs will congregate beneath them in the evening and night. Then the following morning, lift the boards and brush the squash bugs into a bucket of water with dish soap. It won’t catch all of them, but it will make a dent.
- Trap squash bug adults and nymphs in shallow bowls filled with 2 tablespoons of molasses, a splash of cider vinegar, and a pint of water placed beneath the plant’s leaf canopy. If possible, change the liquid bait several times per week and position the bowls so their rims sit level with the soil surface. A word of warning that you may also catch some “good” bugs in these traps, too. If you find you’re catching too many good guys, switch to another method.
9. Spray products for controlling squash bugs
While I do not advocate using commercial synthetic chemical-based spray products or dusts, if you are really struggling with how to get rid of squash bugs and the previous 7 methods have not worked, there are a few organic spray products that will work.
- Insecticidal soap: Made from fatty acids, insecticidal soap breaks down the soft exoskeleton of squash bug nymphs as well as the eggs. Insecticidal soap must come in direct contact with the nymphs or eggs in order for it to work. It is not effective against the adults.
- Neem oil: Neem is another product that’s often recommended for squash bug control. I have hesitation in recommending it, though, because it has systemic properties, which means it is absorbed into the plant and travels throughout its vascular system where it could end up in the pollen and nectar and affect pollinator health. It’s not nearly as detrimental as synthetic systemic pesticides, but it is definitely something to consider when making the choice.
Our online course Organic Pest Control for the Vegetable Garden, provides even more information about managing squash bugs and other pests naturally in a series of videos that total 2 hours and 30 minutes of learning time.
With these 8 methods of squash bug control, gardeners are able to get a solid grip on squash bug numbers and damage. If you have other growing problems in your squash patch, head next to our article on Zucchini Growing Problems which has more useful solutions. You’ll also find more great info about managing pest problems organically in my book, Good Bug Bad Bug.
Have other pests to tackle? Check out the following articles:
- Cabbage worm organic controls
- How to get rid of slugs
- Guide to vegetable garden pests
- How to prevent squash vine borers
- Rose pests