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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>William Bernard</span> Sat, 07/15/2017 - 23:27
Ugh last night I had a beautiful lush pumpkin plant . Went outside to water and it was wilted and dead!???I have other squash and melons that are beautiful close to the dead one that so far unaffected? ? I pulled it up and found some squash bugs and eggs when removing it.could it be possible for the insects to kill it over night? ?????
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 07/19/2017 - 09:25

Hi William,

It's not likely that squash bugs would kill your pumpkin plant overnight. However, it could be that the vine had a squash vine borer in it, which would kill it quickly. Go here to read more https://www.almanac.com/pest/squash-vine-borer#comment-80153.

 

 <span>Poppy Puja Farm</span> Tue, 07/11/2017 - 12:57
Found an exciting way to remove squash bugs; connected a narrow tube on to a shop vac with an inch or two of soapy water at the bottom, worked like a charm
<span>Carolyn Homoly</span> Wed, 06/27/2018 - 01:38
I am going to try this tomorrow. Squash bugs just killed all my zucchini and yellow squash, and have moved on to the cucumbers. Over my dead body will they get my cucumbers!!!!!
<span>Charlie Kincaid</span> Sat, 07/08/2017 - 23:36
I disagree that there is one generation per year of squash bugs. I typically fight them all summer, and even if I kill them and they disappear for a time, they return each time after a few days. They also get on butternut squash.
<span>Andrea</span> Tue, 06/20/2017 - 12:27
Yes, most assuredly, squash bugs are "the enemy", but, to my minds eye, so is commercial pesticides (seven and the like). For the last 3 years (this is the 4th) I have been using neem oil on my squash. So far, the bugs are gone and the plants live and produces abundant amounts of produce. I hope this year is no different. I have also used neem on the grapes, cabbage and cauliflower (works fabulously on the worms that invade them), and the little light green afids on the fruits trees. The Neem did not work on the black acids much to my dismay.
<span>Jerry Myers</span> Sat, 09/23/2017 - 08:56
where do you find neem oil and how do you apply it
<span>Bonnie</span> Mon, 07/23/2018 - 12:39
I would like more detail on the 4TBS neem oil per gallon soil drench. Was it applied before or after squash bugs appeared? How often did you drench the soil under the plants? Is it also necessary to spray the undersides of the squash plant leaves daily ? Any experience with using neem oil soil drench for over wintering squash bugs?
<span>Palerydr</span> Sun, 09/16/2018 - 09:39
I've been using Neem with excellent results for 2 years now. I get mine on Amazon or Ebay. The most important thing is to get 100% pure cold pressed Neem oil ...(and don't leave it sit out, the coons will get it all the first nite) not the most pleasant smelling stull but it works. I fill a gallon sprayer with water and add 4 Tbls. of Neem, 2 heaping Tbls of common baking soda (omit this if used on acid loving plants), and a good squirt of dish soap. Shake well before and even now and then during applications to keep the NEEM oil mixed well with the rest of the ingredients. The baking soda provides an added bonus against blights (early and late) and molds. It makes a alkaline environment on the surface where it's sprayed and those nasty pests can't colonize in it. It's important to start treatment before signs of squash bugs, blights, or molds appear and continue through the season. For blight and mold it will even stop it after you first notice it. If it looks like it's being a little rough on young plants cut the Neem by a half. I use this solution on several things in my garden that are troubled by pests.
<span>Bonnie</span> Mon, 07/23/2018 - 12:39
I would like more detail on the 4TBS neem oil per gallon soil drench. Was it applied before or after squash bugs appeared? How often did you drench the soil under the plants? Is it also necessary to spray the undersides of the squash plant leaves daily ? Any experience with using neem oil soil drench for over wintering squash bugs?