Squash Bugs

How to Identify and Get Rid of Squash Bugs

squash-bugs-pests

The squash bug is sometimes confused with a stink bug, but it can cause much more damage to your plants.

Barbara Pleasant

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What are those bugs on your squash? Squash bugs, probably. Here are tips on how to identify, control, and get rid of squash bugs in your garden.

What are Squash Bugs?

Squash bugs can be the bane of a gardener’s existence! They are very difficult to manage and can cause a lot of havoc. Squash bugs 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.

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 squash bug is fairly large (over ½-inch long) with a brownish or gray body and flat back. The edges and undersides of the abdomen have orange stripes. They are able to fly, but they often simply walk around on plants. Young squash bugs, or squash bug nymphs, are gray and have black legs. They move quickly and often in groups on the undersides of leaves.

squash-bug-nymphs.jpg
Photo Credit: University of Massachusetts Amherst. Newly-hatched squash bug nymphs are small with black legs and move around in groups.

Squash bugs overwinter in your dead leaves, vines, under boards, and even in buildings. They fly to garden plants to mate as soon as vines start forming, and they lay egg masses on the undersides of the leaves. You’ll find adults beneath damaged leaves and near the plant crown.

adult-squash-bug-identiication
Photo Credit: University of Delaware Cooperative Extension. Squash bugs lay small brown eggs on the undersides of leaves.

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 are very difficult to get rid of completely.
  • Pick egg masses off the plants in the morning and later in the day. One reader fills a vase with water and liquid dish soap and flicks the squash bugs into the water. Once the bugs are dead, it’s fine to dump the water anywhere. 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. During the night, both adults and nymphs will congregate underneath the board. Squash between two hard surfaces in the morning and dispose.
  • Insecticides (such as carbaryl/Sevin) are most effective if applied when eggs are hatching. See your local garden center or cooperative extension service for controls that are locally approved.
  • 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.

Squash bugs on pumpkin

How to Prevent Squash Bugs

  • Prevention is key: In the fall, be sure to burn or compost old squash vines to rid your garden of any possible shelters for breeding and over-wintering.
  • Avoid deep, cool mulches like straw or hay that provide an environment that these bugs seem to love.
  • Practice crop rotation.
  • Consider keeping vines covered until blossoming begins. Remove the cover for pollination needs. There is 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.

Plants Affected

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Reader Comments

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A six week  life cycle is the

A six week  life cycle is the average so you may have two generations of squash bugs before harvest in the fall. Squash bugs start laying eggs when your plants are young in early summer. Eggs hatch after about two weeks and the nymphs feed for about a month before becoming adults. The adult females continue to lay eggs during this time

I have found the only way to

I have found the only way to save my squash, pumpkin, and cucumber vines (yes, once they kill all your squash they'll go for your cucumbers!)
1) use a decoy squash plant or two out in the open
2) grow your real squash in raised beds/boxes under ag ribbon
3) once they show up, pick over your plants every day
4) squish the eggs too! if you just scrape them off the leaves and they drop to the ground they'll still hatch
5) use the board/cardboard trick mentioned above
6) sprinkle diatomaceous earth around/on your squad plants- it cuts into their exoskeletons and kills them (warning: it also kills beneficial insects)

I don't use soap on my plants except in very dilute amounts- it does cause burning to the leaves in hot weather.

I live in the high desert in

I live in the high desert in southern california. I'm pretty sure I'm the only house with a garden in quite a large radius and this is my first garden.

I didn't think I'd have to deal with a lot of specialized garden bugs because of my isolation from farms, but these showed up and I can't bring myself to grab them lol.. I would up zip tying a couple pieces of sponge to bbq tongs so I could grab them without crushing them and then dump them in a red solo cup of water and laundry detergent, they drown in a minute or so.

Never gardened before, did a lot wrong but learning a lot and going to scale up big time next year :) Thanks for all the free resources!!

The squash "stink bugs" I

The squash "stink bugs" I have are not even touched by a soapy water spray! I had one survive the wash machine! They are invading my house too! ( Long Island, NY)

I have cleared away all the

I have cleared away all the vines & rot. Nothing but dirt now until next Spring. Is there something to treat the soil with now to rid it of the squash bugs?

Fall clean-up is the best

The Editors's picture

Fall clean-up is the best thing you can do. Wish for a cold winter as freezing temperatures are helpful in destroying the bug populations. Next season be on the lookout for any early bugs and remove them. Spread diatomaceous earth around the base of new plants next spring when the nymphs hatch.

This is definitely my summer

This is definitely my summer squash culprit!! I still have a few flowers on my squash plants but they look very sickly. Would it be worth trying to save them or should I just go ahead and pull them out?

The worth of trying to save

The worth of trying to save your squash plants is something only you can decide.
But consider: What's in harm in letting the plants keep on keeping on? Sometimes plants have enough strength to produce a few fruits, even when over run with these pests.
You could try a few of the solutions posted here (if you have not already), and see if you are able to salvage any of this plant's harvest.

Once the bugs have overrun

Once the bugs have overrun the plant, it is best to pull up the plant carefully and dispose in a large plastic bag. Seal it and put in the garbage.

Here's an easy method to rid

Here's an easy method to rid the squash of those nasty buggers once they have hatched: add a little water in your wet/dry vac, add a tiny bit of soap, and suck the pests off the vine and surrounding area. The soap will drown them fast and doing this daily or so will easily keep them in check! Thanks to my gardening friend, Master Gardener Cindy Rentchsler from Chino Valley, AZ for this awesome tip!

Farmer John is right on!

Farmer John is right on! Vacuuming squash bugs is a safe and excellent way to get rid them. When I find them I vacuum them off with my Dust Buster and dump them into a plastic pail with soapy water and they die very quickly. Works fast with no pesticides.

Rather than using pesticides,

Rather than using pesticides, mix a good dose of dish soap with water in a spray bottle (I use no particular ratio - just enough to make good suds), and spray directly onto the bugs. It only takes a few minutes and they'll be dead in their tracks.

would that work for broad

would that work for broad coverage over the whole garden , through a hose sprayer ? and will they move throughout all my
plants or are they particular to squash , cucumbers ? I have corn and bell peppers , watermelon and strawberries . My brussel sprouts and canteloupe seem only partially nibbled . . . ?

Do you have a problem burning

Do you have a problem burning your plants? I tried this one year and everywhere the soap a pray went, it burned the leaves, causing harm to the plants.

spray organic soap onto bugs

spray organic soap onto bugs in afternoon, then rinse plants in morning.

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