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The cucurbit family, better known as squash, zucchini, pumpkins, winter squash, etc., is easy to grow and can grow prolifically. However, they have their share of garden pests, with squash bugs at the top.
You know what we are discussing if you’ve ever had a squash bug infestation. If not, prepare yourself. This article examines how to identify and get rid of squash bugs in your garden without synthetic pesticides.
What are Squash Bugs
Squash bugs can be the bane of every gardener. Once they appear, a member of the stink bug family (Coreidae) can drive a gardener bonkers.
Adult squash bugs have wings and are about ⅝ inches long and ⅓ inches wide. They have a dark brown or gray, flat body with an orange and brown striped abdomen. Their size makes them easy to spot once they are adults but not easy to get rid of.
Both adults and nymphs have piercing/sucking mouthparts they use to remove sap from plants. They are carriers of a bacterium (Serratia marcescens) that causes cucurbit leaves to turn yellow and die within a few days when injected.
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Squash Bugs vs. Stink Bugs
Squash bugs and stink bugs are similar in shape, and both have a stinky odor when crushed.
- Stink bugs, however, are wider and rounder than the garden squash bug.
- Stink bugs give off a stinky odor even when not disturbed, so you’ll smell them when they are near. A squash bug has to be crushed to smell.
- Stink bugs are more commonly found inside buildings and homes, whereas squash bugs are always found in the garden near pumpkins, gourds, tromboncinos, squash, etc.
- When stink bugs are in the garden, they are not attracted to vegetables such as zucchini or melons; they prefer tomatoes and legumes (peas, chickpeas, peanuts, etc.).
Life Cycle of Squash Bugs
Unmated adults overwinter in the garden under rocks, wood, dead leaves, etc., where they can find shelter to live out the cold weather. Therefore, getting your garden ready for fall will get you far ahead of them for next spring.
Once spring arrives, they come out of hiding and fly to find your prized squash or melon (cucurbit) plants, where they will feed, mate, and lay eggs.
Females lay about 20 reddish-brown or bronze-colored eggs, mainly on the underside of the leaves. Sometimes, the eggs can be found on the tips of leaves and even on the plant’s stems.
Once laid, the eggs hatch in roughly 10 days into tiny, blackish-gray nymphs resembling spiders.
These nymphs then go through 5 developmental stages, called instars, over the next 4-6 weeks.
5 Instar Level Descriptions Of Nymphs:
- Wingless, spiderlike, often covered with a white powder
- Mottled white to light green-gray with noticeable black legs
- Turning darker brown and beginning to resemble adults
- Begin growing wing pads
- After several molts, they are now larger nymphs that have become adults
Nymphs usually congregate in clusters on the bottom side of leaves in all stages and are easy to spot.
They breed and lay eggs once they reach their final instar, beginning a second generation.
In the south, squash bugs can grow two generations in a season. Northward, there is time for only 1 generation.
And the cycle begins again. Therefore, acting quickly when you spot nymphs or adults is critical!
*NOTE:* Once squash bugs reach adulthood, they are much harder to kill as their body is hard-shelled and harder to get rid of.
Plants Squash Bugs are Attracted To:
- Pumpkins
- Melons
- Winter Squash
- Summer Squash
- Cucumbers
Signs of Squash Bug Damage
As we mentioned, these bugs inject a toxin into the plant when they suck the sap out with their sharp mouthparts. This toxin causes tiny specks on leaves that will first turn yellow and then become brown.
Once brown, plants then turn black or dark gray and become brittle. Leaves will begin to fall apart. Smaller plants are killed completely; larger plants may survive but will lose runners.
*Note:* Squash bugs can also feed on the fruits, causing them to be scared and even shrivel up and die.
When all this happens, it’s common to see nymphs and adults scurry away when you get close.
Biological Controls Squash Bugs
Fortunately, squash bugs do have their natural enemies or predators.
- Praying Mantis
- Spiders
- Tachinid Flies
So when you see these in your garden, do your best to work around them and leave to pray on garden pests.
Plants that deter Squash Bugs
Grow plants that will attract natural predators to your garden.
- Dill
- Parsely
- Tansy
- Coriander
- Thyme
How to Get Rid of Squash Bugs
Early detection is critical! As we mentioned, once squash bugs reach adulthood, they are much harder to get rid of. You want to catch them when they are eggs or in one of their nymph stages.
The process can seem overwhelming, but daily diligence will go a long way.
1. Destroy the Eggs
Get in the habit of walking through your garden daily, looking closely at the leaves for clusters of bronze-colored eggs. When you find them, you can do any of these three things:
- Crush the eggs with your fingers. (The eggs are hard but can be crushed)
- Scrape the eggs off the leaves with a butter knife or other object and let them fall to the ground for beetles to eat or into soapy water.
- Use duct tape on your fingers, sticky it out, and press it against the eggs; they will stick to the duct tape. Then, throw the tape into the trash.
2. Handpick into Soapy Water
Fill a bucket with soapy water. Handpick and fling the bugs into the water to get rid of them. This will keep their odor to a minimum.
They are a challenge to catch, but it is worth it to keep the smell down.
3. Place Wooden Boards Under Plants
We used to think this was a crazy idea until we started putting pieces of wood under our watermelons and cantaloupes as they grew to keep them from rotting. By accident, little did we realize we would be attracting squash bugs with these wood pieces.
How to Use: Lay boards flat on the ground near plants and check under them each morning. Destroy any nymphs or adults you find. You’ll be surprised.
4. Use Duct Tape
As we’ve mentioned, for destroying eggs, duct tape can also be used to catch both nymphs and adult squash bugs.
How to Use: Loop the tape around your fingers with the sticky side out. Use it to press or gently touch the bugs. They will stick to it. You’ll find yourself needing to change your tape a lot.
This, along with vacuuming them, has quickly become our favorite method.
5. Vacuum Them
We know this may sound crazy, but just this last spring, our garden was so overrun with them we ran a drop cord out to the garden and used a shop vacuum to suck them into. It was rather gross, but it worked well.
We put soapy water inside the container, and when they were sucked into it, it killed them. Unfortunately, we had to get rid of the shop vac because of the smell that would blast out each time we turned it on after using it to vacuum them. But it worked well. It is much better than using pesticides or harsh chemicals in the garden.
Will Vinegar Kill Squash Bugs?
There is no real evidence that vinegar kills squash bugs. Vinegar at full strength also burns plants. It’s not recommended to use vinegar as a spray in your garden, but it can be used as a weed killer.
How to Prevent Squash Bugs (Natural Controls)
Prevention is a great way to help control them and minimize damage in your garden. You can do several things and try to keep them at bay.
- Avoid using mulch under plants as it provides hiding places for them to hide
- Dispose of any plants showing signs of yellow vine disease caused by their toxic injection.
- Practice good sanitation in your garden. Clean up any old leaves or debris at the end of the season, giving them fewer places to survive over winter.
- Use companion planting—plant nasturtiums and marigolds around your squash and other cucurbit plants.
- Use row covers or netting as soon as you plant the seeds and leave them on until the plants begin to bloom.
- Use Trellisis. Trellising upwards gives squash bugs fewer places to hide on your gourds, squash, etc.
- If possible, use a three-year crop rotation. This will help keep them confused and unable to find desired plants in the spring.
- In the fall, burn old plants to get rid of them or any possible eggs that may overwinter. We bag our old plants and put them in our trash. We never compost them.
- Plant trap crops. Plant crops such as blue hubbard squash to lure squash bugs away from your desired plants for harvest.
- Grow resistant cultivars such as Butternut squash, Improved Green Hubbard, Royal Acorn, or Early Summer Crookneck squash.
Organic Sprays for Squash Bugs
As a last resort, you can use approved organic sprays to help kill squash bugs. However, these sprays also kill beneficial insects.
Does Diatomaceous Earth Kill Squash Bugs?
Yes! This is another option for killing or controlling squash bugs. DE is a powder made from fossilized sea creatures. It contains tiny sharp edges that cut the underside abdomen area of squash bugs and nymphs as they crawl through it.
How to Use: Sprinkle around the base and directly on plants. It can also be mixed with water and sprayed on the underside of leaves. Since it is water-soluble, it needs to be reapplied if it rains.
*NOTE*: As with organic sprays, DE will also kill beneficial insects as they come in contact with it. So you’ll need to decide on your best attempt.
Squash Bugs Can Be Beat!
Yes, squash bugs can be a real nightmare for gardeners, but hang in there, don’t give up. Try all these suggestions in this article and find your favorite way of controlling and getting rid of squash bugs in your garden.
Remember, prevention is key, so start early in the season, watching and looking for eggs and nymphs and destroying them before they can become adults.
What method do you find most appealing and capable of implementing?
Even More Garden Pests To Know
- How to Identify and Control Aphids
- How to Naturally Get Rid of Yellow Jackets
- 5 Ways to Naturally Control Cabbage Worms
- Control Tomato Hornworms Naturally and Get Rid of Them!
- Get Rid of Earwigs and Protect Your Plants with These Simple Tricks
- How to Get Rid of Squash Vine Borers
- How to Kill Tomato Fruitworms
- How to Get Rid of Ants in Your Garden
- How to Get Rid of Slugs in a Garden
Dianne Hadorn is the owner of Hidden Springs Homestead nestled in the hills of East Tennessee. She is a Master Gardener and enjoys helping others learn how to grow and preserve their own food and sharing tips for living a more sustainable life.