Squash Vine Borer

Melittia cucurbitae

Content coming soon for this insect guide.

Insect Profile

Beneficial Rating

-5 Pest

Active Months

JanFebMarAprMayJunJulAugSepOctNovDec

US Distribution

NortheastSoutheastMidwest

Habitat Preferences

Gardensfarms

Taxonomic Group

Moth

Order

Lepidoptera

Family

Sesiidae

Lifecycle

The Squash Vine Borer has one generation per year in northern regions and two in the south. Adults emerge from cocoons in the soil from late June to early July. They lay flat, brown eggs singly at the base of susceptible plants. The eggs hatch in about one to two weeks, and the larvae bore into the stems to feed. The larval stage lasts for four to six weeks, during which they feed on the plant's vascular tissues, causing wilting and eventual death. After this period, the larvae exit the stems, burrow one to two inches into the soil, and pupate in a cocoon where they overwinter.

Overwintering Strategy

Pupae overwinter in cocoons 1-2 inches deep in the soil.

Native Range

North America east of the Rocky Mountains

Attracted By

SquashzucchinipumpkinsgourdsHubbard squashyellow sticky traps

Repelled By

Butternut squashCucuzzirow coversaluminum foilnylon stockings

Organic Control Methods

Organic control methods for the Squash Vine Borer focus on prevention and timely intervention. Physical barriers like row covers (removed during flowering to allow for pollination) or wrapping the base of stems with aluminum foil or nylon stockings can prevent egg-laying. Planting resistant varieties such as Butternut squash or Cucuzzi is also effective. Early planting can help plants become strong enough to withstand an attack. After harvest, remove and destroy all plant debris. Tilling the soil in fall and spring can destroy overwintering pupae. If borers are present, they can be manually removed by slitting the stem and picking them out; the slit portion of the stem should then be covered with moist soil to encourage secondary root growth. Parasitic wasps can be introduced to predate the eggs. Applying Bacillus thuringiensis (Bt) or diatomaceous earth to the stems can also be effective.

Companion Planting

A trap crop of an early-planted Hubbard squash can be used to lure the moths away from other squash varieties. Planting extra squash can also help ensure a harvest despite some losses. While not a repellent, planting resistant varieties like Butternut squash and Cucuzzi alongside more susceptible ones can reduce overall pest pressure.