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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, 06/08/2015 - 12:21

You can tell by the color. Squash bug eggs are copper colored. We've added a better picture to this page for you. 

 <span>Roy Burnett</span> Tue, 06/02/2015 - 10:36
I have an Apricot tree that produces loads of very sweet apricots, --- but every year we find that most of them have eaten spots about 1/8" to 3/8" in diameter. The first year I built a 10ft cage with 3/4" netting to keep the birds out, we got the same eaten spots. This year I changed the netting to 3/8"and had the same problem. Yesterday my wife found several large gray bugs feasting on the fruit, they look just like your photos of squash bugs. Has anybody out there had the same problem ,And if so have you found a solution? Thanks
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 06/05/2015 - 17:23

Squash bugs are a type of "true bug." Although they are not known to attack apricots, there are lookalike true bugs that do, such as various types of stink bugs. They may cause catfacing (corky areas) and deformed fruit. For more information, see:

http://www.epa.gov/pesticides/controlling/stinkbugs/

http://www.ent.uga.edu/peach/peachhbk/insects/plantbugs.pdf

http://fruitandnuteducation.ucdavis.edu/education/fruitnutproduction/Apricot/Apricot_Pests/Apricot_Insect_Mite_Nematode/

http://entnemdept.ufl.edu/creatures/veg/bean/green_stink_bug.htm

http://www.ladybug.uconn.edu/factsheets/BrownMarmoratedStinkBug.htm

 For other apricot pests, see:

http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/apricots.html

http://utahpests.usu.edu/ipm/htm/fruits/fruit-insect-disease/pub-apricot-pests

 <span>Lauradaniels</span> Sun, 01/04/2015 - 17:42
Why are these bugs in my house. I find them all the time on tv screen and many different rooms in my house.
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 01/05/2015 - 15:36

Squash bugs and stink bugs may invade homes in the fall as they look for a warm place to shelter during the winter. They may cluster in attics, walls, etc.

Other lookalikes, such as pine seed bugs, can accidentally come into the home as well during the late summer etc, as they bask in the sun on the south side of buildings.

To deter these bugs, seal up cracks around windows, doors, foundations.

 <span>Darrick</span> Tue, 12/30/2014 - 21:20
I use duct tape to remove both bugs and egg clusters. I have had a terrible problem as I've mulched leaves directly into my garden for years. Once I started my morning rounds with duct tape the zucchini started to flourish.
<span>Jan Bazen</span> Wed, 09/17/2014 - 17:11
The squash bugs destroyed the squash and zucchini before moving on to my watermelons and killing those vines. So once everything is cleaned up and vines destroyed, will using the soapy water kill any eggs and bugs left at end of season? And can the same thing be repeated before planting crops in the spring?
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 09/18/2014 - 10:56

You did the right thing in cleaning up the infected plants but these pests might be back again.  Single (unlated) bugs overwinter under plant debris, then in spring find a mate and start again, leaving eggs on the underside of leaves. A very cold winter could be your relief; they are more likely to survive mild winters.

Neem and horticultural oil and other soap products have been indentified as control agents but good penetration is needed. Consult a local nurseryman for product.

If they show up again, the Colorado extension recommends early season treatment with diatomaceous earth and or pyrethrins, as organic methods.

Next season, consider resistant varieties, rotation to non-cucurbit crops, and/or row covers (these help to keep the bugs from landing on your plants).

Here is further advice, from Utah's coop extenstion (useful in any location): https://extension.usu.edu/files/publications/factsheet/ENT-120-08.pdf

 <span>Mark Clipsham</span> Thu, 08/28/2014 - 17:12
Plant dill with your squash - or tear some off a plant and put it next to the squash and repeat every week or so. Didn't get any squash til last year - first year I started using the dill. All the plants died the many years before after setting fruit and it getting pretty far along. Now I'm the "squash lady". We give away wheel barrow after wheel barrow of squash - I'm planting much less next year. The dill is pretty much gone by now but the plants are big and healthy (last of August); if they all died now I would consider the year a phenomenal success. I am going to start planting a row of dedicated dill from now on every month or so - buy the dill seed in bulk from the coop ("hippie grocery store").
<span>Lung Shepherd</span> Sat, 08/23/2014 - 05:59
The bed bugs are blood suckers, which keep away your sleep during the night. You cannot just get rid of them overnight, but would require competent natural based bed bug treatment products. You can do things on your own by placing the order online and treat this menace on your own.The www.hygeanatural.com helps us for all this problems.