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

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Niney Azman/Shutterstock
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Tips and Tricks for Preventing Squash Bugs

Catherine Boeckmann
Pest Type
Garden Pests
Plants Affected
How to Grow Zucchini & Summer Squash Plants: The Complete Guide
How to Grow Pumpkins: The Complete Guide
How to Grow Winter Squash Plants: The Complete Guide

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 zucchini, winter squash, and pumpkins, but they may also affect other crops in the cucurbit family (like cucumbers, cantaloupe, 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.

Gardening Products
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 ten 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 ÃÛÌÒÁµÈË found each other. She leads digital content for the ÃÛÌÒÁµÈË website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

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Comments

Melvin Wilkes (not verified)

5 years 2 months ago

try using pyrethrum, you can get it I think at either Low's or Menards. I am sure that you can find it on line to at any organic garden supply store. Pyrethrum is a derivative of chrysanthemums, and in the pyrethrum for is a nerve agent against the squash bug and kills it within minutes of contact, also works on the nymphs.
If you find that you have a bad infestation and can not keep up with the egg search you can buy nematodes, I am not sure o which one but you spray the leaves especially on the bottom, however this year the squash bugs were laying eggs everywhere even on neighboring plants, so I spray the nematodes everywhere once I start seeing squash bugs, but the nematodes destroy the eggs.

Rosa (not verified)

5 years 2 months ago

I had never even seen a squash bug in my backyard garden until this year when I saw a huge infestation on each of my 3 squash plants. After harvesting the last few zucchini, I dosed each plant with diatomaceous earth and turned each plant over and buried them all. No sign of any bugs since then. Will doing this kill them and deter them from coming back next spring?

Unfortunately, there’s no guarantee that they won’t return next year, especially if you grow squash plants again (or if your neighbors do). Adults overwinter in dead leaves and other plant matter, so make sure that you clean up around your garden to remove and expose any good hiding place to the elements. If they do return next year, consider taking a year off from squash and growing veggies that are less desirable to them, like leafy greens or root vegetables. 

Amy (not verified)

5 years 2 months ago

The health dangers and risks associated with using commercial insecticides far outweigh the convenience of "getting rid" of bugs. I'll take my chances with bugs over getting cancer anyday.

healthyworld.org/sevin.html

Annette Reed (not verified)

5 years 2 months ago

I have a ton of these all over my spaghetti squash and zucchini. We have sprayed multiple times to no avail. Any suggestions on what else to do would be appreciated.

Kendra (not verified)

5 years 2 months ago

Nothing will help but manual removal of them. Also, get rid of the eggs. I have found that squishing them between my fingernails works, as does duct tape, rolled around your hand, sticky side out, to remove them from the plant.

Gale Green (not verified)

5 years 4 months ago

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!

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.

Tom (not verified)

6 years 1 month ago

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.

Robert and Carol M. (not verified)

2 years 6 months ago

Short answer: No.

Neither does Sevin.