Trying to control squash bugs can seem like an insurmountable task when you find them in your vegetable garden.
If you grow zucchini or squash, you may be familiar with trying to deal with a squash bug infestation. These bugs can do a huge amount of damage, particularly to new plants.
Young seedlings and plants that are flowering are most vulnerable to an invasion of squash bugs.
Squash bugs are easy to identify based on their distinctive eggs which the bugs lay on the leaves that they enjoy eating.
These 11 easy tips will keep your garden pest-free. Take charge and find out how to kill squash bugs for good.
What are squash bugs?
The botanical name for squash bugs is Anasa tristis. This bug is very common in the USA and gets its common name from the fact that it is attracted to and lays its eggs on squash, as well as pumpkin plants.
I’ve also seen the bugs on cucumber plants and other curcubits such as melons.
What do squash bugs look like?
The adult squash bugs measure about 5/8 inch long and about 1/3 inch across. Their color varies from dark brown to dark gray. The back of the body is flat.
The underneath of the abdomen and sides of the body has orange stripes.
Squash bug eggs
Their eggs are elliptical shaped and have a dark color to them. They are small – about 1/16 inch in size with a hard shell.
Normally these eggs are on the underside of the leaves especially along the veins of the plant, but the ones on my plant were in plain sight on top!
Eggs hatch in approximately 10 days, and the squash bug nymphs which emerge from the eggs mature in about four to six weeks.
Squash bugs life cycle
The key to the control of squash bugs is to interrupt their life cycle since they have just one generation each year.
The complete life cycle of the squash bug is approximately 6-8 weeks. In colder climates, these bugs have one generation per year. In warmer climates there will be 2 or 3 generations.
The females live over the winter in plant debris and then come out in the spring to lay their reddish browns eggs on the leaves of cucumbers, squash, melons and pumpkins.
Squash bugs damage
An infestation of squash bugs can do a lot of damage to your plants.
These bugs feed on leaves, vines and even the fruit of your plants. Squash bugs suck the sap out of leaves of plants that they feast on. This causes yellow spots which will turn brown and cause the plant to wilt.
They do most of their damage on younger plants. (more mature plants seem to be able to withstand their feeding a bit better but can still be badly damaged by the pest.)
Damage caused by squash bugs is destructive. Not only do they feed on plants, they also release a saliva during the feeding which carries a bacteria that is toxic to curcubits.
Squash bugs vs stink bugs
It’s easy to see why some gardeners mistake the two bugs – squash bugs and stink bugs look quite similar. Each bug also has a foul odor when squashed and have hard outer shells.
Stink bugs are wider and rounder than squash bugs. Squash bugs will do much more damage to your garden than stink bugs will.
Stink bug eggs are light colored. Squash bug egg are darker. The image below shows the two bugs and how they differ.
They are not the only bugs which have a similar look. The spined soldier bug and dock bug are also look a-likes for the stink bug.Vegetable gardens will soon be full of squash and zucchini. But that means there will be squash bugs too! Find out how to control this pest in your garden. Click To Tweet
Squash bugs aren’t the only insect pest that plagues us in the summer months. Flies are a real problem too. See how I used the original Pine-Sol to make a homemade fly repellent here.
Adult squash bug image source – Wikimedia Commons
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 . One 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 and eliminate squash bugs 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 fall will reward you with less 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 have a tendency 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 change 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 which are not affected by this pest.)
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 with mulching any plants.)
Plant squash bug resistant varieties
If possible, search out plant varieties that are resistant to squash bugs. There are some squash types are seem to not be so easily infected by them. These varieties are good choices:
- 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 eggs 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
There are some plants and herbs which squash bugs seem to avoid, so planting them near squash and other curcubits is a good idea. These include:
- Mint (in containers is best. Mint can be quite invasive.)
- Marigolds (calendula)
- Bee balm
How to prevent squash bugs: – attract beneficial insects
Squash bugs prevention means trying to attract beneficial insects that feed on them. You do this by having plants near by that welcome insects which 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 fly, plant dill, Queen Ann’s Lace, carrots, cilantro or calendula near your squash plants. They have pollen and flowers that will attract the fly.
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 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 get 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
It is is a natural pesticide which 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.
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 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.
Pin this post on controlling squash bugs for later
To remind yourself of this post for how to kill squash bugs, pin this image to your gardening board on Pinterest so that you can easily find it later.
Squash bug eggs image source – Wikimedia Commons
What have you found effective in dealing with squash bugs?
Controlling Squash Bugs Printable
This printable gives a handy chart of tips to rid your yard of squash bugs for good.
- Cardstock or glossy photo paper
- Deskjet Printer
- Load the card stock or glossy photo paper in your printer.
- Print out the chart for controlling squash bugs.
- Laminate (optional) and display in your garden shed, or keep in your garden journal.
Be sure to choose landscape and "fit to page" on your printer settings to print out on a normal sized sheet of card stock.
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Thursday 13th of April 2023
I have dealt a lot with squash bugs. Best way is hand pick & remove eggs. The eggs are usually nearly laid, slightly oblong and reddish brown. Best time is early or late afternoon. Water plants ...that drives them up to climb ( they don't like getting wet) and will force them to move & be easier to spot the adults. The younger nymphs are white or pale, and are normally clustered. Wear gloves (cuz squash leaves are prickly) & it will be less gross to crush the bugs. Best deterrent. You can also plant one plant earlier to be a trap plant and attract the bugs to it. . I usually have ones that sprouts on its own, so I use it.
Wednesday 27th of July 2022
Thank you SO much for all this information! I have never even heard of squash bugs before and this is our second year with them 😠! I have tried some of these tips already, but after reading all of this, I think I may be able to get a handle on them for next year! Thank you again!!
Monday 30th of August 2021
My yellow squash were infested with squash bugs and powdery mildew. The squash continued to grow but they grew white! Are they still edible white?
Monday 30th of August 2021
There is a disease that can happen by eating some plants in the squash family that have been infected by disease. It is called toxic squash syndrome. IF you bite into squash that is extremely bitter, the plant may have been infected.
Sunday 8th of August 2021
I use tulle cloth to cover my Zucchini plants. It works really well. The biggest problem is that the cloth tears very easily. Then I have to sow the hole closed.
Secondly, I have to be the bee and pollinate the flowers myself. It's not a big deal. In order to cover the Zucchini plants I bought some 1/2" PVC pipe and bent them over my raised beds about every 3' forming a half hoop.
I also put the 1/2" PVC pipe horizontally on top of and over my half hoops and tied this horizontal PVC pipe in place with some light string. My raised beds are built our of 2" x 6" treated boards. On top of these boards I nailed into place a 3/8" x 1.5" strips of treated wood set off center. You will have to rip some 2"x6" treated boards to get the desired strips. To keep this cloth in place I used paper binders that would open to the thickness of the offset strips and clipped the cloth to these strips.
The tulle cloth can be purchased from a wholesale house much cheaper than a fabric shop; and, it comes in 9' widths. This seems to be the right width for a 4' wide raised bed. Over time the cloth does stretch. The squash bugs and stink bugs seems to be controlled. It is now early August and the plants do not seem to be bother by these bugs. However, smaller bugs like aphids can still be a problem. To set this system up can be a little costly. However, gardening is a hobby. Hobbies do get to be expensive.
Best of luck.
Monday 9th of August 2021
Thanks for the tips, Jerry.
Tuesday 23rd of February 2021
I definitely disagree with the use of tachinid flies. They are killing our monarchs and other butterflies.