Squash Vine Borer: How to Identify, Prevent and Control Them

Squash plants are a staple in many gardens. They produce abundant fruit that is versatile enough to be used in various recipes. However, if you’re not vigilant in caring for your squash plants, they can fall prey to the squash vine borer, a pest that can destroy an entire crop quickly. In this article, we’ll discuss how to identify, prevent, and control them.

What is a Squash Vine Borer?

The squash vine borer (Melittia cucurbitae) is a type of moth that lays its eggs on the stems of squash plants. Once hatched, the larvae bore into the stem, causing damage and eventually killing the plant. Adult borers are active from June to August and can lay up to 200 eggs per season.

Identification of Squash Vine Borers

The first step in preventing and controlling squash vine borers is to be able to identify them. The adult borer is a wasp-like moth with clear wings and metallic green or blue coloring on its body. The eggs are small and reddish-brown, and they are usually laid in clusters at the base of the plant's stem. The larvae are white with brown heads and can grow up to one inch long.

Preventing Squash Vine Borers

Prevention is the best way to avoid a squash plant infestation. Here are some tips:

Plant Resistant Varieties

Some squash varieties are resistant to squash vine borers, such as Butternut, Royal Acorn, Sweet Cheese and Seminole. By planting these resistant varieties, you reduce the chances of an infestation.

Protective Barriers

You can protect the base of your squash plant stems by wrapping them with aluminum foil or floating row covers. This barrier will prevent the adult moths from laying their eggs.

Clean Up Garden Debris

Remove all garden debris before winter to help reduce the number of squash vine borer cocoons that can survive over the winter.

Delay Planting

Wait until late June or early July to plant your squash plants. This will cause the plants to outgrow the first generation of moths, reducing the chances of egg-laying and larvae infestations.

Controlling Squash Vine Borers

If you suspect that your squash plant has already been infested, you need to take quick action to control the situation. Here are some methods:

Handpicking

If you only have a few borers, you can handpick them out of the plant. Look for entry holes at the base of the stem and remove the larvae with a sharp knife or wire.

Insecticides

If the infestation is severe, you may need to use insecticides specifically designed to kill squash vine borers. These products contain chemicals such as carbaryl or permethrin. Be sure to read the label carefully and follow the instructions for application.

Natural Predators

You can also introduce natural predators of the squash vine borer, such as beneficial nematodes, trichogramma wasps, and braconid wasps. However, these methods are not always effective and may require several applications.

Squash Vine Borer damage on plant.

Squash vine borers can be a devastating pest that can kill off an entire garden crop in a short amount of time. However, by taking preventative measures and being vigilant for signs of infestation, you can reduce the risk of losing your crops. If you do find yourself dealing with an infestation, there are options available to help you control it. By following the tips outlined in this article, you can keep your squash plants healthy and productive throughout the growing season.

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