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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>D.b.</span> Sun, 09/16/2018 - 15:08
I've also had trouble with these pests on my peppers and certain flowers (yep - peppers). The only truly effective deterrent I've found is a product called BioNEEM, from Safer. Apparently, it disrupts the desire to reproduce and feed. VERY EFFECTIVE. I've found it to be effective on most garden pests, including grasshoppers. You can find it on Amazon. Check it out and good luck!
<span>Sandra</span> Fri, 08/05/2022 - 20:58
I use Neem for many things but for me, it didn't work on squash bugs.
<span>D.b.</span> Sun, 09/16/2018 - 15:10
Apparently, it's also an acceptable control for organic producers.
<span>Jessie Pnte</span> Sat, 03/30/2019 - 22:53
DB the Product you mentioned by Safer was it Neem Oil?
<span>Anne</span> Mon, 09/23/2019 - 12:25
Safer has an excellent "Insecticidal Soap" product.
<span>Dan</span> Mon, 07/15/2019 - 18:25
i use a combination of Murphy's oil soap and dish detergent that proves effective but the board technique was new to me.
<span>Krista Wilson</span> Wed, 07/24/2019 - 00:09
This sounds fantastic. What is the ratio you use?? I have lost 3 of my 7 plants to the hugs this year.
<span>Carole</span> Thu, 05/02/2019 - 02:16
I think you meant DE. Diatomaceous Earth. It's a natural silica the will shred internal organs of small pests. Be careful of your worm population also.
<span>Virginia Johnson</span> Sun, 09/16/2018 - 10:47
I am surprised and frankly dismayed that Sevin or such heavy duty chemical pesticide was suggested as a control for squash bugs in an otherwise very informative article. I would suggest there are other more natural sprays that an organic grower (backyard gardeners too) can use to effectively deal with squash bugs. (Garlic sprays and also Dr. Bronner's Peppermint & Hemp Castile Soap - for a couple controls - are what we use on our small farm in Nevad, when all else seems to fail. Thanks for listening; Virginia, at Custom Gardens Organic Farm.
<span>Deborah M James</span> Fri, 10/11/2019 - 01:25
Seven didn't work for me anyway. I haven't been able to grow pumpkins for three years now. The Squash Bugs allow my plants to grown fairly large, giving me a false hope that the plants will survive, but then decimate my plants. This year I was desperate and poured two whole bottles of Seven on the plants after the Squash bugs took over. I intended to destroy the plants with Seven on them but was hoping to get rid of the bugs once and for all. It didn't work at all. I lost my entire crop of pumpkins, squash, zucchini again this year. Bastards.