Are Squash Bugs Harmful to Humans?

While tending to your home garden in late summer, your squash patch or cucumbers are wilting, discolored, or dead. The leaves underneath are covered in white or pale-yellow spots, and there are brown/black colored bugs everywhere. Squash bugs now overrun your garden and are damaging your plants; and you need to remove them, but are they going to bite you? Are they going to cause you harm? Do you need to get a professional in to exterminate them?  

Squash bugs (Anasa tristis) are not harmful to humans, even though their saliva can carry cucurbit yellow vine disease and be toxic to plants. The squash bug may only cause discomfort to humans when it is disturbed or squished as it releases an unpleasant aroma. 

Follow along below if you are an avid gardener, just starting, or wondering what these

brown-colored bugs are. We will discuss whether squash bugs bite humans and are toxic and how they affect your garden. There will also be a couple of proven control and prevention methods to keep squash bugs out of your garden discussed. 

Do Squash bugs bite humans?

Squash bugs specifically need carbohydrate-rich food to survive, so they feed on plants with pumpkin being a favorite choice.  Squash bugs are carriers for Anasa wilt and cucurbit yellow vine disease (Serratia marcescens), which only affect plants and not humans. Squash bugs do not bite humans or pose any risk to the health of humans other than their stink.

However, squash bugs do “bite” plants as they puncture the fruit and leaves, injecting toxic venom into the plant. The sap and other nutrients of the plant are sucked up, resulting in the plant being unable to circulate nutrients and water around the plant. The plant will eventually darken in color, wilt, and die.

Squash bugs are most likely to eat plants part of the Cucurbitaceae family. This family includes squash, watermelon, honeydew, cantaloupe, cucumbers, luffa, pumpkin, and zucchini. Pumpkin is a particular favorite of the squash bug. Other squashes such as butternut, acorn, summer, and winter are at high risk of damage.

How to identify squash bugs

There are three different types of squash bugs that are of concern to your garden:

  • Anasa verania (Southern squash bug)
  • Anasa tristis (Western squash bug)
  • Anasa coecuta (cotton stainer squash or spotted summer squash bug)

The Anasa coecuta is easily identifiable by its orange and black head. At the same time, the Anasa verinia has mainly black coloring with either a yellow or orange stripe. The identifying feature of the adult Anasa tristis (the article’s main focus) is its greyish-brown to brown-black coloring. On the outside of the abdomen, there is often a row of brown or gold dots. The dark color palette and the minute dots often make the squash bug appear as tiny black bugs. The shape of this squash bug is shield-shaped and flat. The Anasa tritis will be about half-inch long.

The squash bug lays yellowish to bronze, oval-shaped eggs, which are 1/16 inch long. The nymphs that hatch from these now bronze eggs go through instars (five stages of growth). These young nymphs hatch at 1/10 inch long and progress to half-inch long as adults. The coloring of young nymphs starts with black legs and heads with a light green abdomen. As the nymphs grow larger and older, they will first turn a light grey and progress to a brownish-grey with antennae and black legs.

The Squash bug is most active during springtime, as this is when they mate and feed off cucurbit plants. Female squash bugs appear in gardens from early spring to the middle of summer. The females will lay tiny clusters of about 20 to 30 brownish eggs on the underside of the plants’ leaves. You will observe the eggs between the veins of the leaves and occasionally on the stems.

After about ten days, the squash bug eggs will hatch, with the young nymphs taking four to six weeks to mature. If your garden has been recently disturbed, you will find both the nymphs and the adults under the leaves.

Another way to identify squash bugs in your garden is by the damage done to the plants. Due to squash bugs transmitting toxins into the plants, your plants will appear yellowed, have unformed fruits, and stunted growth. There will also be no flowers present on your squash plants.


How to get rid of and prevent squash bugs 

There are a couple of organic and natural ways to get rid of and prevent squash bugs from destroying your season’s crop. When attempting to prevent and get rid of squash bugs:

  • It is crucial to detect squash bugs early while they are still eggs. Getting rid of adult squash bugs entirely from your garden is harder.
  • Once you spot squash bug eggs on your plants, start picking them off by scraping the eggs off the leaves and letting them fall to the ground. You can scrape off the eggs with your fingernail or a butter knife. Beetles will eat the eggs on the ground. It is essential to check your plants weekly for eggs as they hatch in about ten days.
  • As you see them, you can flick adult bugs of the plants into a bucket filled with soapy water, which will kill them. The bucket of soapy water and dead squash bugs can be emptied down the drain. 
  • Companion planting around plants most affected by squash bugs is a great way to repel them. Plants that repel squash bugs include tansy, nasturtium, catnip, and dill. Sacrificial plants like squash and pumpkin can also be planted to draw the bugs away from your good plants.
  • Get rid of old vines, compost, broken branches and any other shelters in your garden that provide squash bugs a place to breed and stay over winter.
  • Keep the layers of mulches like hay and straw thin as squash bugs love thick layers of mulch to breed and hide.
  • Protective row covers can be placed over your plants to keep out squash bugs. The protective row covers will need to be removed to allow pollination at the plants’ bloom time.   

We have not mentioned pesticides as a preventative or control method. Most often, pesticides kill beneficial insects like bees. Pesticides also do little to prevent squash bugs from hiding and breeding in nearby mulch, old vines, and shelters. 


Squash bugs are a nuisance that often leaves your plants looking very sad with wilted leaves, dead flowers, fruit, and dead plants. Fortunately, it is straightforward to identify the squash bug and start some preventative and control measures.  

It is vital to be proactive in getting rid of and preventing squash bugs in your garden. Removal of squash bugs and eggs is achieved by handpicking them off plants and removing the eggs before they progress into adults. Harvest guards can also be purchased and used to protect your plants against squash bugs. Follow a few of our recommended prevention and control methods if you are overwhelmed by the number of squash bugs in your garden or want to get ahead before breeding season starts.

Even though squash bugs carry plant toxins and can kill your plants, you don’t have to worry about them biting you or harming you. They only stink when squished or disturbed.


I enjoy all things outdoors and I love plants! I've never considered myself to be one with a green thumb, but it's my mission to learn, so I figured I would bring you along for the ride. :) Happy planting!

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