Tips for getting rid of squash bugs

Story and Photos by Kristi Cook

It happens every year. Carefully tended squash seedlings slowly mature into dark green, leafy bushes loaded with yellow blossoms, causing my mouth to water in anticipation of the summer’s first squash. And much to my dismay, I am never alone in my drooling. Tiny invaders – aka squash bugs – also lurk about, dreaming of sucking the life out of every squash plant before a single fruit reaches my dinner plate. It took a few years of trial and error, but I finally landed upon several organic tactics that not only keep these nasty creatures in check, but also allow my plants to produce heavy crops until I’m ready to let them go. 

The first line of defense during any battle is “Know the enemy.” Both adults and nymphs happily feed on any cucurbit including pumpkins, cucumbers, and watermelons with squash seemingly being their favorite. Employing piercing-sucking mouthparts, nymphs and adults suck sap from every above ground plant part including the fruit. Once fed upon, leaves develop yellow spots and turn brown before quickly dying. This feeding also disrupts the flow of nutrients and water throughout plant tissues, causing plants to wilt if feeding is heavy. Left unchecked, even the healthiest plants succumb to damage.

To minimize damage and prolong plant health, search every plant for eggs, adults, and damage at least every other day. Adults and nymphs usually hang out on the undersides of upper leaves, but be sure to search the lower levels as well. Gently pull back mulch near the stems and you’ll likely find more than a few congregating in the cool darkness. Newly hatched nymphs seem especially fond of this area, while older nymphs and mating adults tend to be a bit braver, often preferring the undersides of crunchy leaves lying on the ground. Plop any squash bugs you find into a cup of soapy water to drown. (It’s a cruel world in the garden!)

Eggs can be found on any plant part. However, the most common location is the undersides of leaves in the V-shapes created by leaf veins. Carefully scrape eggs off with a wet fingernail and crush the hard casings. While it may be tempting to flick the squashed eggs on the ground, I find it’s better to toss them in the soapy water to be flushed down the drain, just in case my efforts fail.

Adult females lay clusters of 10-20 yellowish to bronze elliptical eggs on all aboveground cucurbit parts. Within 10 days, 1/10-inch nymphs emerge, resembling little more than whitish, light green, or black abdomens with hairlike, blackish legs.

The squash bug’s preference for the cool darkness of cover can be used to your advantage. Before the coolness of evening settles in, place boards, cardboard, even some of those crunchy old leaves under the plant’s canopy in direct contact with damp, but not soaked, soil. Early the next morning (keyword here is early) stage an ambush. With soapy water in hand, inspect under each board or leaf and snatch any unsuspecting squash bugs. And while this may sound weird to some, I am convinced these creatures learn the sound or feel of the gardener’s footsteps and hide in anticipation of attack. So, that said, tread lightly as you move about destroying your enemy.

Handpicking is by far the most effective – and time-consuming – method I have employed over the years. However, placing floating row covers over seedlings and leaving in place until the blossoms open saves me several weeks of scouting. The trick is to secure the edges well, as these bugs are persistent and will crawl under loose covers.

Over the course of five to six weeks, nymphs progress through five stages, or instars, as they increase in size, darken in color, and develop wings. Once mature, the large, gray to dark brown adults (appx. 5/8 inch) set about producing even more progeny.

Just remember that cucurbits depend on pollinators, so covers must be removed to allow for pollination. Many gardeners “open” the rows in the early morning when bee activity is greatest and replace midmorning when activity declines. Unfortunately, I find our summers are too hot for even the lightest cover once fruiting begins; however, every garden is different so it’s worth trying if your summers tend to be on the mild side.

While hand-to-hand combat is certainly the most direct approach, other methods work to your advantage as well. Encourage plant vigor, which helps plants withstand attacks, through adequate organic fertilization, sufficient water, and soil-cooling mulch. Practice crop rotation and select insect-resistant varieties when possible. And finally, remove debris in the fall to reduce overwintering sites.

Squashing adults is not always effective, as they are tough and resilient. It’s best to drop them into soapy water to drown and then flush them down the drain.

While organic methods may not completely eliminate the dreadful squash bug, when performed with diligence, plant stress will be reduced to a minimum, allowing you to reap an ample harvest … all while keeping your garden’s ecosystem intact.



Organic Solutions

Organic pesticides to combat squash bugs do exist. Some use neem and pyrethrum with varying results. However, as I’ve mentioned before, in more than 20 years of organic gardening I have never had a pest problem that warranted these measures – and hopefully I never will. I attribute this success to careful – preferably organic – practices that encourage optimal soil and plant health and high levels of beneficials. Should you utilize organic pesticides, just as with any pesticide, follow directions carefully, using only what you absolutely must as no pesticide targets a single species and has the potential to harm the good guys, too.

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