Squash Vine Borer

The squash vine borer is a serious pest that can cause significant damage to cucurbit crops. It’s important to monitor your cucurbit crops for the presence of squash vine borers and to take steps to control infestations as soon as possible to prevent significant damage.

Host Plants

The squash vine borer (Melittia cucurbitae) is a pest that primarily feeds on plants in the cucurbit family, including:

• Squash (summer and winter)
• Pumpkin
• Zucchini
• Melons
• Cucumbers

In addition to cucurbits, the squash vine borer can also attack other members of the gourd family, such as gourds and ornamental plants like the moonflower.

Regions impacted

The squash vine borer is native to North America and is found throughout the United States and Canada.

Description

The squash vine borer is a moth in the family Sesiidae. As an adult, it has a wingspan of about 1 inch (2.5 cm) and is orange-red in color with black markings. The hind wings are translucent with a bright orange fringe.

The squash vine borer larva is a pale yellow, legless grub that can reach up to 1 inch (2.5 cm) in length.

Life Cycle

The life cycle of the squash vine borer involves the following stages:

• Egg stage: Female squash vine borers lay their eggs on the stems of cucurbit crops, such as squash, pumpkin, zucchini, melons, and cucumbers. The eggs are usually laid singly and are covered in a powdery substance.
• Larval stage: The eggs hatch into larvae, which are pale yellow, legless grubs that can reach up to 1 inch (2.5 cm) in length. The larvae tunnel into the plant’s stems and feed on the sap.
• Pupal stage: The larvae eventually pupate inside the stems of the plant.
• Adult stage: The pupae emerge as adult moths, which are orange-red in color with black markings. The hind wings are translucent with a bright orange fringe.
• Overwintering: In regions with cold winters, adult squash vine borers will overwinter in protected sites, such as leaf litter or other debris near the base of the plant.

Damage and Detection

The larvae feed inside the plant’s stems, tunneling into the stem and feeding on the sap. This feeding can cause the stems to wilt, yellow, and eventually die, leading to a significant reduction in yield.

To detect squash vine borers, you can look for the following signs:

• Wilting or yellowing of leaves: If you notice wilting or yellowing of leaves on your cucurbit crops, it could be a sign of squash vine borer damage.
• Sawdust-like frass: If you see sawdust-like frass (excrement) near the base of the stem, it could be a sign of squash vine borer damage.
• Exit holes: If you see small, round exit holes in the stem, it could signify that the larvae have pupated and emerged as adult moths.

Prevention and Control

Preventing squash vine borer infestations requires a combination of cultural, preventive, and control measures. Here are some steps you can take to prevent squash vine borers:

• Practice crop rotation: Rotating your cucurbit crops to a different location each year can help reduce the build-up of squash vine borer populations.
• Clean up debris: Destroying crop residue after harvest can help reduce the number of overwintering sites for squash vine borers.
• Early detection: Monitoring your plants regularly for the presence of squash vine borers and controlling infestations as soon as possible can help prevent significant damage to the plant.
• Row covers: Covering plants with row covers can prevent adult squash vine borers from laying eggs on the stems of the plants.
• Stem wrapping: Wrapping the stems of your cucurbit crops with a material such as aluminum foil or tree wrap can prevent squash vine borers from tunneling into the stems.
• Timing of planting: Planting your cucurbit crops later in the season, after the main flight of adult squash vine borers has passed, can help reduce the impact of these pests.
• Companion planting: Some plants are believed to repel squash vine borers and can be used as companion plants in the garden. Plants often used as companion plants for cucurbit crops include marigolds, nasturtium, and radishes.

Here are some steps you can take to get rid of squash vine borers:

• Mechanical control: Hand removing and destroying egg masses and larvae can help reduce the population of pests.
• Chemical control: If necessary, insecticides can be used to control squash vine borers. Chemical controls should be used as a last resort, and it’s important to choose an insecticide that is safe for use on food crops and to follow all label instructions carefully.

It’s important to monitor plants for the presence of squash vine borers and to control infestations as soon as possible to prevent significant damage to the plant. If you have questions or concerns about squash vine borers on your plants, it is best to consult with a local horticulturist or agricultural extension office for specific recommendations for your area. They can provide guidance on effective control measures and can help you determine the best course of action for your specific situation.