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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

<a title="View user profile." href="/author/editors">The Editors</a> Mon, 02/29/2016 - 14:37

One of the most common squash pests is the beetle, but this does not sound like that. (The beetle has a triangle-shape "shield" on his back—but no gel. Yes, you know that.) 

It sounds like you are a victim of the squash borer. Take a look at the pics of it here and you'll find several suggestions for eliminating or combatting it lower on the page: http://www.almanac.com/content/squash-vine-borer

Here's a bit more; note especially the last paragraph and best last chance at keeping, maybe not saving, the plant: http://www.extension.umn.edu/garden/insects/find/squash-vine-borers/

Slugs are famous for their gelatinous trail. Here is a little more on those: http://www.almanac.com/content/slugs

 

We hope this helps.

<a title="View user profile." href="/author/editors">The Editors</a> Mon, 02/29/2016 - 14:37

One of the most common squash pests is the beetle, but this does not sound like that. (The beetle has a triangle-shape "shield" on his back—but no gel. Yes, you know that.) 

It sounds like you are a victim of the squash borer. Take a look at the pics of it here and you'll find several suggestions for eliminating or combatting it lower on the page: http://www.almanac.com/content/squash-vine-borer

Here's a bit more; note especially the last paragraph and best last chance at keeping, maybe not saving, the plant: http://www.extension.umn.edu/garden/insects/find/squash-vine-borers/

Slugs are famous for their gelatinous trail. Here is a little more on those: http://www.almanac.com/content/slugs

 

We hope this helps.

 <span>Erich Walz</span> Fri, 02/19/2016 - 20:42
I have had good luck controlling them by wetting down the leaves in the late morning. The squash bugs must not like getting wet because once I am done they run up to the top side of the leaves to dry off. I just pick them off into my cup of soapy water. Doing this allows me to see where the adults are at and then I can find the egg masses on those plants and remove with duct tape.
<span>Danny Finigan</span> Tue, 09/08/2015 - 17:51
Great info in this piece. I too have found early detection and persistence to be key in controlling these bugs. I use a little butane torch on the egg masses and bugs. A small portion of the leaf will be burned but this method seems to work pretty well. I've had some very large and productive squash plants this year despite the presence of the bugs. I learned a lot, and next year will be even better I'm sure.
<span>Lynne Cota</span> Fri, 09/04/2015 - 11:06
Very helpful info concerning the squash beetle. I believe burning all the infected plants at season's end will go along way to get rid of them next year. I do have wood raised beds, so I'll probably always have to do close inspection during squash season. Thank you again for the solutions. lpc
<span>Bill Mcdonald</span> Wed, 07/22/2015 - 16:52

should i pick squash being eaten by squash bugs?

<a title="View user profile." href="/author/editors">The Editors</a> Fri, 07/31/2015 - 12:01

You can harvest mature squash that has been attacked by squash bugs. The squash should be safe to eat, as long as there are no rotten areas (which you'd want to cut out). If you have used an edible-crop-approved pesticide, be sure to read the label to determine the amount of time you need to wait until it is safe to harvest the crop; wash the squash thoroughly before eating.

 <span>Melody Pietrzyk</span> Thu, 07/02/2015 - 15:26
I spent a better part of my afternoon ridding my plants of squash bugs and eggs. I dropped the eggs and bugs in a bucket of soapy water. Unfortunately I knocked over the bucket in the garden with all the eggs and dead bugs.... Will the eggs still hatch? Im so mad right now. I lost all my pumpkins and squash plants to the pests last year I am on a mission to save them this year.
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 07/06/2015 - 15:19

The eggs will probably not hatch if they are not attached to a leaf. You can cover the area with cardboard or newspaper mulch or put some black plastic or landscape fabric down to be on the safe side.

 <span>Bubby</span> Sat, 06/06/2015 - 14:50
I usually find clusters on the underneath sides of the leaves in July. Today I checked my plants, the fruit is growing nicely, not big enough to pick, but I swear I see what looks like an egg here and there on the stems and the squash themselves. Nothing on the leaves though and the 'eggs' I see are not in clusters. Are these eggs??