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How to Identify and Get Rid of Squash Bugs in the Garden

Image Credit:
Niney Azman/Shutterstock
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

Let’s squash the squash bug population! Squash bugs can be the bane of a gardener’s existence, sucking the life out of your precious cucurbit plants. Here are tips on how to identify, control, and get rid of squash bugs in your garden.

What Are Squash Bugs?

Squash bugs are very difficult to manage once their numbers get out of control and can cause a lot of havoc.

They are most commonly found on squash plants (hence the name), such as pumpkins, winter squash, and zucchini, but they may also affect other crops in the cucurbit family (like cantaloupe, cucumbers, and watermelon). Other pests that are commonly found on squash include squash vine borers and aphids.

Generally, they attack young tender plants and seedlings, causing them to wilt and die. However, they cause little damage to plants in late summer and fall.

Note: Squash bugs are often mistaken for stink bugs, as they are similar in appearance, and both have a foul odor when squashed. However, stink bugs are wider and rounder than squash bugs.

Identification

How to Identify Squash Bugs

The adult squash bug is a flat-backed insect that is fairly large (over 1/2 inch long) and usually dark gray to dark brown.

The edges and undersides of the abdomen have orange stripes. Although they can fly, they often simply walk around on plants.

Young squash bugs, or nymphs, may be gray or light brown and have black legs. They move quickly and often congregate in groups on the undersides of leaves.

Squash bugs overwinter in dead leaves, vines, under boards, and even in buildings.

In early June, they mate, laying small clusters of eggs (about 20) on the undersides of the leaves, and the females will continue to lay eggs through mid-summer. You’ll find adults beneath damaged leaves and near the plant crown, where they use their piercing mouthparts to suck out nutrients from the plant.

Squash Bug Damage

These bugs inject a toxin into the plant and suck the sap right out of it with their sharp, sucking mouthparts. This causes yellow spots that eventually turn brown. The leaves will wilt because the damage prevents the flow of nutrients to the leaves, and then they will dry up and turn black, crisp, and brittle. The leaves also sometimes have ragged holes. Smaller plants will die, and squash bug feeding can decimate young fruit.

The wilting can resemble bacterial wilt, which is a disease spread by cucumber beetles (yet another squash pest), so be sure to find the bugs or eggs and identify them correctly.

Control and Prevention

How to Get Rid of Squash Bugs

  • Early detection is critical! You want to catch squash bugs before they grow into adults, or they become very difficult to get rid of completely.
  • Pick bugs off the plant early. Fill a bucket with water and liquid dish soap and flick bugs into soapy water. Once the bugs are dead, it’s fine to dump the water anywhere.
  • Pick egg masses off the plants in the morning and later in the day. You can also simply scrape the eggs off the leaves with a butter knife and let them fall onto the ground, where beetles will eat them. Eggs hatch in about 10 days, so be sure to check for them on at least a weekly basis.
  • Place a board or shingle in the garden at night (or pieces of newspaper). During the night, both adults and nymphs will congregate underneath the board. Squash between two hard surfaces in the morning and dispose of them.
  • Keep checking your plants at least daily. If there are no more than a few vines infected, keep collecting and destroying the bugs and crushing the egg clusters that you find on the undersides of leaves.
  • Remove plant debris during the growing season to reduce sites where squash bugs can hide. 

Using pesticides

Insecticides are not effective in managing squash bugs once they are adults, so don’t bother trying.

In the event that you catch the squash wilting very early in the season and you catch this when eggs are hatching, then insecticide application is probably needed to manage it. See your local garden center or cooperative extension service for controls that are locally approved. The best time to apply pesticides is early morning or late at night (during minimum bee activity). Be sure to spray underneath the leaves, where most squash bugs are found.

It is not necessary to treat squash bugs found in the garden during late summer or fall.

Squash bugs on pumpkin

How to Prevent Squash Bugs

  • Prevention is key: In the fall, burn or compost old squash vines to rid your garden of any possible shelters for breeding and overwintering.
  • Avoid thick layers of mulches like straw or hay that provide an environment that these bugs seem to love.
  • Practice crop rotation.
  • Consider keeping squash plants covered until blossoming begins. Remove the cover for pollination needs. There is typically only one generation of squash bugs per year, and you can avoid them by covering your plants for the first month of spring. You can also delay planting your squash until the early months of summer.
  • Companion planting can be useful in repelling squash bugs. Try planting nasturtium and tansy around your plants that are commonly affected by squash bugs.
  • Select varieties of squash that are resistant to the squash bug if you have a big problem. ‘Butternut’, ‘Royal Acorn’, and ‘Sweet Cheese’ varieties are all more resistant to squash bugs.
  • Clean up cucurbits and other plant matter in the fall to reduce the number of overwintering sites.

Garden Pests

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann is the Executive Digital Editor of Almanac.com, the digital home of The Old Farmer’s Almanac. She leads digital editorial strategy and publishing across a wide range of Almanac sub...

Read more from Catherine Boeckmann

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Comments

<span>King Ralph</span> Fri, 05/27/2022 - 14:02
squash bugs , and stink bugs, have developed resistance to seven dust...it is ineffective in north carolina squash and stink bugs.....you must use a special type of super seven to have any effect...see your local feed and seed store....
<span>Ruth Merrill</span> Thu, 07/08/2021 - 16:22
I read and tried wrapping my finger with duct tape. The eggs and the bugs stick to it, it works perfectly.
<span>Jan Jack</span> Mon, 05/31/2021 - 20:00
There is a very simple way to avoid getting squash bugs and cucumber beetles at all. Simply do not sow your seeds until the middle of June. By the time your plants are up and have their first primary leaves those insects are long gone...on to other gardens where the food source is up and tasty. It will NOT DELAY your harvesting by much as it is warmer by mid June and the plants catch up quickly. I'm 76 and this was my grandfather's practice.
<span>Bev</span> Sat, 08/19/2023 - 14:55
Is this for specific zones? I’m in zone 7a
<span>Cheryel Lemley…</span> Mon, 05/31/2021 - 13:08
I read about bay leaf treatment, tried it, ground up some old bay leaves to a powder, dusted one plant, and watched with glee as they all scrambled away.
<span>Mary</span> Mon, 05/31/2021 - 11:45
In response to Lynn LaMar, you are gardening in the wrong season. In zone 10 our growing season is the fall and winter. Zucchini's are hard to grow here in the best of times, but impossible in the heat and humidity of summer.
<span>Jennifer Cresap</span> Fri, 08/14/2020 - 13:49
You can also put fire or smoke ash in with seed or plant when you plant. It provides some prevention.
<span>Jennifer Cresap</span> Fri, 08/14/2020 - 13:45
We spray a neem oil and dish soap solution on everything including squash and pumpkin . This has been pretty effective . We have to spray every five days or so . This is an all natural option . We still do checks we get a few here and there. Check leaves for eggs pull those or scrap and burn leaves or put in neem solution.
<span>Lynn Lamar</span> Thu, 06/18/2020 - 09:28
Believe it or not, at 69 years old I am a 'new gardener' in SW Florida, of all places. lol I researched what I could grow and where and how and I'm happy happy with my little garden BUT. I had planted only 5 zucchini plants since it's only me and I've already lost 3 with 1 more in the wings under destruction. I've read all about bugs and nothing seems to fit the description of what's happening to my plants. I've just started 3 more babies and they're coming up strong. I've done everything recommended short of "the board." I don't see anything except little black dots under the leaves in the morning and I remove and squash them. I just bought very expensive organic essential oil spray "Dr. Earth Final Stop" that has stopped nothing...Use food grade DE around the base and that seems to slow things down. Also, Mrs. Meyer's hand soap with water in a spray bottle also seems to slow things down. My tomatoes look fine. My beans look fine. I have containers of rosemary, mint and lavender stationed right next door, yet, the destruction continues. I have one little guy struggling to grow and he looks shriveled and done for. This is crazy!! What's next folks????
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 06/18/2020 - 11:58

Could you describe in more detail what's happening to your plants? We may be able to help identify the culprit.

Aside from squash bugs, the other main pests of squash tend to be slugs (when plants are young) and squash vine borers (when plants are a little older). However, the issue could also be unrelated to pests—are they getting enough water, too much direct sun, etc.