Squash Bugs In Home Gardens - University Of Minnesota Extension

Damage caused by squash bugs

Squash bugs primarily attack squash and pumpkins, although they can also attack other plants in the cucurbit family, such as cucumbers.

• They suck the sap out of leaves with their piercing-sucking mouthparts. Their feeding causes yellow spots that eventually turn brown.
• The feeding also affects the flow of water and nutrients, and, when severe, can cause wilting.
• Squash bug is the vector of yellow vine decline, a new disease in our region.
• Larger, sturdier plants are more tolerant of feeding damage, while young plants may die because of feeding.

Managing squash bugs in home gardens

Cultural controls

• Maintain healthy, sturdy plants through proper fertilization and watering to help limit squash bug damage.
• Remove plant debris during the growing season to reduce sites where squash bugs can hide.
• Clean up cucurbits and other plant matter in the fall to reduce the number of overwintering sites.

Physical controls

• Crush eggs that are attached to the undersides and stems of leaves.
• Remove and kill nymphs and adults by dropping them into a pail of soapy water. This is practical only if a few plants are affected.
• Removing squash bugs can be challenging because squash bugs hide under leaves and move quickly when disturbed.
• Trap squash bugs by laying out boards or pieces of newspaper. Squash bugs will group under the boards at night; you can then collect and destroy them in the morning.

Using pesticides

Insecticides are normally not required to manage squash bugs.

Managing squash bugs on farms

Monitoring

• Start scouting for egg masses in July.
• Treatment is most effective on freshly hatched nymphs, so monitoring egg numbers helps in timing effective controls.
• Consider treatment if you find an average of one egg mass per plant.
• Eggs hatch 7-10 days after being laid.

Cultural controls

• Squash bug adults spend the winter in plant debris. Remove crop residues and keep field borders mowed and free of debris.
• If squash bugs are a consistent and severe problem, avoid straw mulches, which give squash bugs the extra shelter they seek at night.
• Some varieties of squash are more tolerant of squash bug damage. Studies have shown that butternut and buttercup squash, and sweet cheese pumpkins tolerate squash bug feeding more than other varieties.

Trap cropping can be used to draw squash bugs outside of the planting. Studies have shown perimeter plantings of blue hubbard squash can draw squash bugs out of crops. The trap crop should still be managed to reduce squash bug populations through thorough egg squashing or insecticide application.

Physical controls

Eggs can be scraped off leaves and squashed during scouting.

Chemical controls

• Chemical controls are most effective on nymphs. Scouting helps time insecticide applications for shortly after nymphs hatch.
• Nymphs often hide on the underside of leaves, so good spray coverage is important
• This pest is active when vine crops are flowering, so remember to protect pollinators when selecting products and making applications. Apply later in the day when flowers are closed.

For insecticide control options, see the Midwest Vegetable Production Guide.