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How to Control and Prevent Squash Bugs in Your Garden

By Stephanie Smith
prevent squash bugs

If you have cucurbit vegetables such as pumpkins or summer and winter squash on your gardening list, you can expect squash bugs to find their way to your garden. These prevalent pests can do an enormous amount of damage to winter squash and pumpkins in particular, but they may strike related cucurbits such as melons and cucumbers. By preparing yourself before problems arise, you can keep squash bugs from stealing your cucurbit crop.

Squash Bug Life Cycle

Adult squash bugs are dark gray-brown and measure about 5/8 inch long. In some adults, gold and brown spots alternate along the edge of the abdomen. Their shield-like shape often gets them mistaken for broader stinkbugs, but squash bugs only damage cucurbits. Stinkbugs are much less particular. Adult squash bugs typically live up to 130 days, and two generations per season are common. Adults lay very distinctive shiny, copper-colored eggs beginning in late spring or early summer, which soon hatch into hungry offspring known as nymphs.

During the 33 days before full adulthood, nymphs molt repeatedly and pass through five stages called instars.1 Light green nymphs emerge from eggs and become progressively larger and darker gray with each instar stage. Both nymphs and adult squash bugs feed on cucurbit plants, often congregating in very large numbers.

Squash Bug Damage

When feeding, mature and immature squash bugs pierce the tissue of cucurbits and suck out the plant juices. They feed on leaves, vines and even fruit. The damage done by squash bugs is particularly destructive; they pierce plants in multiple sites, causing vines and leaves to collapse as they suck the sap.

In addition, squash bug saliva released during feeding carries bacteria toxic to cucurbit plants. This causes the injured leaves to wilt, and eventually the plant dies. In some cases, infected nymphs and adults carry the cucurbit yellow vine disease bacterium. Also transmitted via saliva, this may kill plants that might otherwise survive a squash bug assault.1

kill squash bugs
Pest ID & Prevention

Cultural Controls

Smart gardening practices used to care for your garden can reduce the number of pests, including squash bugs, and help keep your plants healthy. Cultural practices such as regular inspections and good garden sanitation are very important in fighting squash bugs.

Squash bugs like to congregate under objects, such as boards and tarps, during the active season. You can set these objects in the garden near cucurbit crops, and then destroy the squash bugs that hide under them. Also check plants regularly for eggs and destroy any egg masses you find on the plants.

Mulching around cucurbits during the growing season is counterproductive, as it gives the squash bugs a place to hide. Mulches can also give adult squash bugs a place to overwinter. Keep your gardens clean of all old cucurbit vines and crop or leaf debris. With winter hiding places removed, squash bugs rarely survive the cold, so it cuts down on cucurbit invasions the next season. Tilling the soil well after harvest also goes a long way toward eliminating these pests. 2

Effective Control Products

One of the best ways to control squash bugs and keep your cucurbits healthy is to use an effective control product proven to fight difficult squash bugs. Sevin® Insect Killer Ready to Use kills squash bugs and more than 500 other insect pests, including stinkbugs, by contact. You can treat squash, pumpkins, cucumbers and melons right up to one full day before your harvest.

Squash family plants rely on insect pollination to form their fruit, so avoid spraying open blooms where beneficial pollinators, such as squash bees, may visit. With Sevin® Insect Killer Ready to Use and its adjustable spray bottle or Sevin® Insect Killer Concentrate, used with an adjustable pump sprayer, you can easily control the coverage area of your treatment spray to get the precision application you desire. Treat squash plants in the evening to avoid contact with bees that visit plants early in the day, and always follow label instructions. Be sure to cover the undersides of leaves as well as other plant parts.

Squash bugs pose a problem for many vegetable gardeners, but GardenTech® and Sevin® brand garden insecticides are here to help. By following these recommendations, you can minimize squash bugs and their damage and enjoy more of the goodness and nutrition your homegrown produce can offer.

Always read the product label thoroughly and follow the instructions carefully, including guidelines for pre-harvest intervals (PHI) and application frequency.

Sevin is a registered trademark of Tessenderlo Kerley, Inc.

GardenTech is a registered trademark of Gulfstream Home and Garden, Inc.


1. J. Capinera, "Squash Bug," University of Florida Entomology & Nematology, February 2014.

2. W. Cranshaw, "Squash Bug: Management in Home Gardens," Colorado State University Extension, January 2013.



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