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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>Cj</span> Sun, 09/16/2018 - 10:04
I plant radishes in succession every two weeks amongst my squash plants throughout the season and the squash bugs stay away. I started this after a couple of seasons of crazy invasions. If I only plant them once, it doesn't help. As soon as the radishes start to mature, the bugs are back. I discovered this by accident and went back to my garden diary to make sure nothing else had changed, but this was it. For me, it is a surefire squash bug repellent, though, I have to say it makes no sense to me either.
<span>Jen</span> Sun, 09/16/2018 - 09:54
You didn’t mention it, but squash bugs love tomatoes as well. They are always on my tomatoes, eating the surface, although that may not be what initially drew them to my garden.
<span>Annette Reed</span> Mon, 09/16/2019 - 06:29
I have a huge infestation on my squash, but have never found any on my tomatoes. I have, however, noticed a lot of stink bugs. They have a similar look but are bigger. Are you sure you don't have stink bugs on your tomatoes?
<span>Allen Melson</span> Thu, 08/30/2018 - 13:49
For 3 years now, after planting at the beginning of May I religiously go out and pick squash bugs off all my vining plants; Squash, butternut squash, cantaloupe, cucumbers, pumpkins, zucchini, and even pole beans, this morning I even found them on my bell peppers, and I drop them in a soapy solution. I have filled two, gallon sized, bottles with these bugs and their carcasses and still they are everywhere. I have companion planted, sprayed Neem oil, sprayed organic soap, scraped off eggs and they are still everywhere. Right now my routine is to gently spray down the plants, to get the bugs to come to the tops of the leafs and then hand pick them. Then I go back and check for eggs and once ever couple of days spray a soapy solution and/or neem oil on the vines and leafs. I have even used sevin in a pinch. In the garden I do not use mulch and have placed stone around the raised beds. In the winter I do a complete clean out and burn the vines giving them no place to bed over the winter. This year is the first year I have been able to keep the majority of my vining plants alive, although all the zucchini plant succumb to them. Help me! PLEASE In the article you state there is only one generation per/year, what do you mean by that? How can I finally rid myself of these things?
<span>April Silveira</span> Wed, 08/29/2018 - 21:34
I’ve pulled all my zucchini and squash plants for the season. I had squash bugs but the plants were hearty and still grew several zucchini and yellow squash from each plant. I’ve been using a fly swatter to kill the bugs when I saw them and now that the plants are gone will the bugs go away? Do they hibernate in the winter? I live in Utah so it will be cold, will that help kill them off? Any advice will be appreciated.
<span>Terry Finley</span> Tue, 08/21/2018 - 08:40
Wow! After reading these responses, it sounds hopeless! You can never find all of the bugs and eggs to pick off, and spraying kills the bees! Actually no acceptable solution here ! ☹️
<span>Rhenda Pence</span> Sun, 04/07/2019 - 18:18
Neem oil in water with a little bit of soap as a wetting agent in a spray bottle. Thoroughly spray every week or so, more if the infestation is bad. It may not totally get rid of them at first because they proliferate so quickly in the spring, but it will keep them under control and eventually you'll get the upper hand. It is only dangerous to "bad" bugs, in that only the ones that eat the plant are effected by it. It also helps with powdery mildew.
<span>Pam Griesinger</span> Sun, 07/29/2018 - 19:43
How do you tell the difference between a squash bug and triatominae? The one I photographed was mostly yellow, not so much brown as squash bug...
<span>Frances</span> Tue, 06/26/2018 - 08:54
I placed plastic bowls between each plant, in them I put some water and a little squirt of dish soap. The next day each bowl had a squash bug or bugs. I changed the water every other day. I made up a quart of squeezed garlic, with cayenne pepper, Tbsp, maybe, just dumped it in, and a squeeze of dish soap. Poured that around the stem every other day. Bug are essentially gone. Found a couple small deposits of eggs, but not the dozens that would be here by now. I'm checking for eggs every other day. The adult bugs are dead in the soap water. But our season is just getting going. I see below someone used Neem oil and I'm going to add that.
<span>Frances</span> Tue, 06/26/2018 - 08:56
I didn't add to fill the quart with water after putting in the garlic and cayenne and soap.