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How to Identify and Get Rid of Squash Bugs in the Garden

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Tips and Tricks for Preventing Squash Bugs

Catherine Boeckmann
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Pest Type
Garden Pests
Plants Affected
How to Grow Zucchini & Summer Squash: Planting, Care & Harvest Tips
How to Grow Pumpkins: Complete Guide to Planting, Harvesting, and Storing
How to Grow Winter Squash: Butternut, Acorn, Spaghetti & More

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.

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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.

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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 loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
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Comments

Catherine Cox (not verified)

2 days 9 hours ago

So glad to read this info unfortunately the critters did their damage and I removed my zucchini plants. But I got a few squash. Next year I'll be able to fight em off!!! Or prevent em from attacking my favorite veg. Thank you!

bob s (not verified)

2 weeks 6 days ago

Very timely article. I used straw mulch on my zukes and I'm seeing what appear to be squash bugs on the plant, near the crown, for the first time today and picked them off. Should I remove the mulch to provide the bugs less cover and make them easier to find? Nasturtium seeds go in today.

Thanks.

There are different thoughts about mulch when it comes to squash bugs. The bugs do like to shelter in/under mulch (whether straw, plastic, cardboard, etc), however some experts say that the benefits (discouraging weeds, encouraging beneficial insects, conserving moisture, etc.) may outweigh the disadvantages. Also, some experts suggest that squash bugs tend to prefer the organic mulches, such as straw, over plastic etc., as the straw mulch can be cooler and moister. If you are seeing a lot of squash bugs, you might try removing the mulch to see if that reduces their numbers. Or, try a plastic mulch (especially a reflective type) to see if that might help. 

Idaho gardener (not verified)

11 months 2 weeks ago

A friend suggested painting the egg clusters with brush on white out to suffocate the eggs so they don't hatch. I've tried it this year and it seems to be working well!

Lori Gordon (not verified)

11 months 2 weeks ago

wish it was where I could send an article from this site to family or post on Facebook

James N (not verified)

3 years 1 month ago

Why do roaches almost always die on their backs? The Almanac show publicly.

Cockroaches have a high center of gravity due to their long legs, so when they die, they tip over and have no way of righting themselves, especially on smooth surfaces.

Debbymerrifield (not verified)

3 years 10 months ago

Holes in all my growing spaghetti squash. I picked them all not rip yet. What bug is it? And should I throw them all out?

pull your plants just had a ton and insecticide won't touch them