Squash Bug

Anasa tristis

Adult squash bug [Credit: Oorangeaurochs ]
Adult squash bug [Credit: Oorangeaurochs ]
Juvenile squash bugs
Juvenile squash bugs
Squash bugs attracted to a pumpkin in the autumn
Squash bugs attracted to a pumpkin in the autumn

Host Plants:

On Crops: Squash, pumpkins

Where Found:

Throughout North America, wherever squash is grown


Adult squash bugs are large, mottled gray stink bugs the size of a thumbnail. Although they are able to fly, adult squash bugs are most often seen lurking among squash foliage, looking for mates. Females lay groups of reddish-brown eggs on leaves, which hatch into fast-moving young squash bugs with gray bodies and black legs. Young squash bug nymphs tend to feed in groups, often on leaf undersides or on ripening fruits.


Squash bugs use sharp, sucking mouthparts to feed on sap and juices from squash and pumpkin plants. Heavy feeding can leave ragged holes in leaves, and young fruits can be ruined by squash bug feeding. If feeding continues uncontrolled, plants become weak and stop producing.

Preventing Problems:

Use row cover (garden fleece) to protect plants for their first month or so in the garden, or until they begin flowering heavily and need to be visited by bees and other pollinators. Delaying planting of your main crop of squash until early summer can reduce squash bug problems. You also can use highly attractive zucchini as a trap crop. With all squash and pumpkins, check foliage for squash bug eggs twice weekly in summer, and rub them off with a wet cloth or scrape them off with a table knife. Eggs that fall to the ground are eaten by crickets and ground beetles, who mistake them for weed seeds

Managing Outbreaks:

Place old towels or open pizza boxes under infested plants and jiggle the leaves to make squash bugs drop to the ground. Shake the collected bugs into a tub of soapy water. Also place towels or boards beneath plants overnight. First thing in the morning, gather and drown squash bugs hiding under the covers. Neem sprays can help slow the growth of young squash bugs and reduces egg-laying by adults. In mid fall, after the first frost, place a small pumpkin where squash grew that year. On warm days squash bugs will come out and gather on the pumpkin, where you can collect them in soapy water.

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