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

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Niney Azman/Shutterstock

Tips and Tricks for Preventing Squash Bugs

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.

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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.

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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 website companion of The Old Farmer's Almanac. She covers gardening, plants, pest control, soil composition, seasonal and moon c...
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Comments

<span>Vicki Bower</span> Mon, 09/09/2013 - 12:44
I have cleared away all the vines & rot. Nothing but dirt now until next Spring. Is there something to treat the soil with now to rid it of the squash bugs?
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 11/01/2013 - 09:58

Fall clean-up is the best thing you can do. Wish for a cold winter as freezing temperatures are helpful in destroying the bug populations. Next season be on the lookout for any early bugs and remove them. Spread diatomaceous earth around the base of new plants next spring when the nymphs hatch.

 <span>Alymcpea</span> Wed, 07/10/2013 - 12:19
This is definitely my summer squash culprit!! I still have a few flowers on my squash plants but they look very sickly. Would it be worth trying to save them or should I just go ahead and pull them out?
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 07/12/2013 - 16:15
The worth of trying to save your squash plants is something only you can decide. But consider: What's in harm in letting the plants keep on keeping on? Sometimes plants have enough strength to produce a few fruits, even when over run with these pests. You could try a few of the solutions posted here (if you have not already), and see if you are able to salvage any of this plant's harvest.
<span>Cyrtonyx</span> Thu, 07/31/2014 - 17:00
Once the bugs have overrun the plant, it is best to pull up the plant carefully and dispose in a large plastic bag. Seal it and put in the garbage.
<span>Cvfarmerjohn</span> Wed, 05/15/2013 - 14:12
Here's an easy method to rid the squash of those nasty buggers once they have hatched: add a little water in your wet/dry vac, add a tiny bit of soap, and suck the pests off the vine and surrounding area. The soap will drown them fast and doing this daily or so will easily keep them in check! Thanks to my gardening friend, Master Gardener Cindy Rentchsler from Chino Valley, AZ for this awesome tip!
<span>Jbush</span> Fri, 11/22/2013 - 14:29
Farmer John is right on! Vacuuming squash bugs is a safe and excellent way to get rid them. When I find them I vacuum them off with my Dust Buster and dump them into a plastic pail with soapy water and they die very quickly. Works fast with no pesticides.
<span>Augusta</span> Mon, 09/24/2012 - 09:00
Rather than using pesticides, mix a good dose of dish soap with water in a spray bottle (I use no particular ratio - just enough to make good suds), and spray directly onto the bugs. It only takes a few minutes and they'll be dead in their tracks.
<span>Katr</span> Fri, 06/20/2014 - 12:12
Do you have a problem burning your plants? I tried this one year and everywhere the soap a pray went, it burned the leaves, causing harm to the plants.
<span>Bobster</span> Tue, 07/21/2015 - 12:48
spray organic soap onto bugs in afternoon, then rinse plants in morning.