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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>Gale Green</span> Fri, 07/05/2019 - 10:43
A gardener friend told me to plant icicle radishes as soon in Spring as possible, in a circle large enough to plant squash/etc. in. Wait till the radishes bloom (let them 'go to seed') then or slightly after the first of June (we live in zone 7) plant your squash. By that time either the squash bugs will have moved on, died out for the season, or been repelled by the radishes allowed to bloom. I've tried this with some success. Have run into a few late hatching squash bugs, but in such a decreased number that I could easily trap them under boards and/or pick them off. Gardeners seem to/tend to have a 'bragging rights' attitude toward who plants what the earliest or first. Forget it. Plant later...and the squash bugs, for the most part, will have gone to your earlier planting competitors!
<span>Robert And Carol M.</span> Fri, 05/27/2022 - 07:11
They enter the plants at the base, put your bug killer there and use Sevin. My pal and I have used Sevin for over 40 years and we're still kickin'. Do NOT believe the bs propaganda that it is harmful to people and pets. It isn't. It only affects the "nasties", the bugs.
<span>Tom</span> Wed, 09/26/2018 - 10:25
I checked my spaghetti squash the other day and had a bunch of small bugs on running around on the squash. They were and I assumed that they were young squash bugs. The squash was ready to be picked so I picked them and cut out the vines. My question is, does the presence of these bugs effect the edibility of the squash or other fruit that they may live on.
<span>Robert And Carol M.</span> Fri, 05/27/2022 - 07:12
Short answer: No. Neither does Sevin.
<span>Annette Reed</span> Mon, 09/16/2019 - 06:24
The answer is yes. I have a huge problem with squash bugs. I have sprayed multiple times and cant get rid of them. I have not had any problems with them affecting the edibility of the squash. My zucchini and spaghetti squash have been fine to eat. If the damage to the skin is severe, just peel the skin off. The fruit inside is fine.
<span>Robert And Carol M.</span> Fri, 05/27/2022 - 07:06
Get Triazicide at Lowe's, or your favorite store, follow the instructions. I put it on my plots and containers and the slugs/grubs in my older garden popped out the ground and I tossed them onto the concrete. Worked like a charm. There are non in my newer areas... yet, but if I keep using Tz, hopefully there never will be. Spread it out and water it in GOOD. You'll be surprised... and it isn't harmful to people or animals and pets. Have a nice summer.
<span>Kathy</span> Wed, 09/19/2018 - 15:56
I didn't plant any vines and I bought 2 pumpkins the other day and they have squash bugs on them eating the pumpkins is that normal?
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 09/20/2018 - 14:39

Sometimes pests will hitch a ride on crops after they're harvested and shipped out to stores. Remove the bugs from the pumpkins and they won't be a problem.

 <span>Thomas Fowler</span> Sun, 09/16/2018 - 21:07
I will not use insecticides, so I experimented this year with DE. Fantastic experience...works on cucumbers as well. Fewer ticks in the leaf mulch that we use...? Can that be a real thing?
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 09/20/2018 - 14:33

The only thing you have to consider when using DE is that it will also kill pollinators (bees, butterflies, etc.) if sprinkled on and around flowers. Therefore, it's recommended that you only use DE on garden plants when they are not in flower or when you can ensure that pollinators won't accidentally come into contact with it.