Control Squash Bugs 12 ways – How to Kill Squash Bugs

Trying to control squash bugs can seem like an insurmountable task when you find them in your vegetable garden.  These 12 easy tips will help you take charge and learn how to kill squash bugs for good.

A squash bug (Anasa tristis) is a destructive garden pest that feeds on squash, zucchini, pumpkins, and other cucurbit plants. Both adults and nymphs damage leaves and vines by sucking plant sap, which can lead to yellowing, wilting, and reduced harvests. They are easily identified by their distinctive eggs, laid on the leaves that the bugs enjoy eating. 

If left untreated, squash bug infestations can quickly spread through a vegetable garden during the growing season. This guide explains how to control squash bugs naturally, including hand removal, neem oil, diatomaceous earth, and prevention methods to help protect your plants

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Why squash bugs are harmful

Squash bugs can weaken and destroy squash plants quickly, especially during warm weather and on young plants.

Heavy infestations reduce plant vigor, damage vines and leaves, and may lead to smaller harvests or collapsed plants if left untreated.

Tips to control squash bugs

Looking for tips on how to kill squash bugs in your garden? The first thing to remember is that treatment seems to work best if it takes place when the plants are young and also when they are flowering. 

Early detection of squash bug nymphs is very important. Once you have a big infestation of adults, they can be very difficult to kill.

Many beginning gardeners make the vegetable garden mistake of neglecting to inspect for bugs, and yet that is the start of the solution.

Here are some ways to try to eliminate squash bug infestations and some ideas for organic squash bug control:

Garden cleanliness helps with squash bug control

The adult bugs are attracted by garden refuse. Remove vines, leaves, and plant debris in the late fall and destroy them.

This will ensure that they will not be in the areas in your garden that attract the bugs when it is time to plant your vegetable garden.

It is tempting to leave vines and debris until the following spring, but doing this just gives bugs and disease a breeding ground.

Time spent cleaning away vines and dead plants in the fall will reward you with fewer problems next year.

Garden refuse can be recycled in a compost pile, but don’t have it too close to the areas where you will be planting your vegetables.

Don’t compost your dead plants in the fall.  Those little pests tend to overwinter and will cause trouble all over again the next growing season.

How to kill squash bugs by practicing crop rotation

Many garden problems occur when you plant the vegetables in your garden in the same spot each year. Instead, rotate the crops often, so that the bugs and diseases don’t get a chance to really take hold.

It is good to rotate your crops each year, replacing those varieties that are prone to infestation. 

Choose a planting area where squash bug-resistant varieties were grown the year before (or where other crops grew that are not affected by this pest)

Find out more about crop rotation here.

Mulch can harbor bugs

We all love mulch for its ability to control weeds and conserve moisture, but mulch can also attract squash bugs.  Bare soil in vegetable gardens seems to work better for me than mulched soil when it comes to deterring squash bugs.

Squash bugs love to hide under the mulch and use it as a protective cover. If you do want to use it in your vegetable garden, don’t lay the mulch right up to the base of the plant. (A good idea when adding organic leaf mulch to any plants.)

Plant squash bug-resistant varieties

If possible, search out plant varieties that are resistant to squash bugs. There are some squash types that seem not to be so easily infected by them. These varieties are good choices:

• Butternut
• Early Summer Crookneck
• Improved Green Hubbard
• Royal Acorn

For a zucchini variety that is not as attractive to squash bugs, try growing zuchetta tromboncino rampicante. This variety is a relative to both zucchini and yellow squash, and has a similar flavor to its cousins.

If you can’t find resistant types in your store, be sure to inspect the undersides of the leaves often for egg clusters and destroy the infested leaves.

What kills squash bugs?

Timing is a factor in controlling squash bugs.

Planting squash a bit later in the season works if you have the time for this and your growing season is long enough. The majority of the bugs will have already hatched and perished earlier in the year.

For this reason, a second planting of squash often does better than the first!

Use companion plants that repel squash bugs

Certain herbs, flowers, and trap crops are often incorporated into a squash bug management strategy. While these plants won’t eliminate squash bugs on their own, they may help support natural pest control efforts by masking plant odors, attracting beneficial insects, or serving as trap crops.

See our complete guide to plants that repel squash bugs for recommended flowers, herbs, and trap crops.

How to prevent squash bugs: – attract beneficial insects

Squash bug prevention means trying to attract beneficial insects that feed on them. You do this by having plants nearby that welcome insects that love to eat squash bugs.

What eats squash bugs? There are some insects that are very beneficial to have on your side when you are fighting pests. One of these is the Tachinid Fly (Trichopoda pennipes) 

This bug is also known as the caterpillar fly. This fly also helps to control Japanese beetles and grasshoppers, and a few other pests.

This little bug can be very effective in helping to control squash bug populations. The female fly lays her eggs on the adult squash bugs. When the eggs hatch, they burrow into the squash bug to feed, eventually killing the bugs.

To attract tachinid flies, plant dill, Queen Ann’s Lace, carrots, cilantro or calendula near your squash plants. They have pollen and edible flowers that will attract the flies.

How to kill squash bugs

Sometimes, even if you have practiced good garden cleanliness and planted wisely, you may wander out one day and find these bugs enjoying a meal of squash leaves.

Instead of reaching for the insecticides, there are other things that you can do to prevent squash bugs from doing their damage.

Remove infestations immediately

Ignoring a squash bug infestation will just make it worse in the long run, since it will allow them to take over the plant. If you find infested leaves, remove them from the plant and destroy them.

Don’t forget to inspect cucumbers, melons, and pumpkins. Squash bugs love them too!

Hand-picking of squash bugs

Be vigilant with young plants. If you notice squash bugs on plants, hand-picking of the bugs is very effective.   

Examine your plants often and crush the eggs when they are spotted.  Be especially vigilant early in June, which is a common time for the eggs to be laid.

To pick off the bugs, simply inspect the plants and pick off any adult bugs you may find and drop them in a bucket of soapy water.

You will generally find the bugs on the underside of the leaves or at the base of the plants.

Using wide packing tape with the sticky side out, wrapped around your hands, is also a great way to pick the bugs off the plants.  This will allow you to pick the eggs off the leaves. You can discard the tape later.

This can be a daily job, and if you decide to let it go for a few days, you may end up with a problem that is not so easy to control.

Squash bugs organic control –  neem oil and diatomaceous earth

With vigilance, insecticides are often not necessary, but if you do develop an infestation that you cannot manually control, you may need to use them. I like to choose organic options when possible. 

Some to try are:

Neem oil for squash bugs 
Neem oil is a natural pesticide found in seeds from the neem tree. It is yellowish brown in color, has a bitter taste, and smells like garlic/sulfur.
It is a natural pesticide that effectively controls this pest. Spray it on all leaf and stem surfaces as the label suggests.

Neem oil coats the surface of the squash bug eggs, rendering them less likely to hatch into adults, and it will kill off both the new nymphs and mature adults.

Some gardeners use Neem oil mixed with baking soda as a prevention for squash bugs and also to treat powdery mildew.

Diatomaceous earth

This powder is made from the fossilized remains of tiny, aquatic organisms called diatoms.

Applications of diatomaceous earth around the base of the plant can be an effective method in controlling squash bugs. It is a treatment that is also considered organic.

This powder does not work as well on adult squash bugs because of their hard shells, but it does help to get rid of the squash bug nymphs.

Note: Be careful not to get diatomaceous earth on the blossoms of the plants, because this product affects not only squash bugs and other, more beneficial insects, which are attracted to the pollen of flowers.

With a bit of care in both planting and tending of your plants, you should find that you can control these pests for good this year.

For more information on other invasive pests, see this post on dealing with invasive pests.

Admin note: This post first appeared on my blog in June of 2013. I have updated the post with additional information and new photos, as well as a printable for your garden journal and a video for you to enjoy.

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Admin note: This article on how to control squash bugs first appeared on the blog in June 2013. This post has been updated with new photos, a printable how-to card, and a slideshow video about controlling squash bugs.

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