How to Prevent and Get Rid of Squash Bugs (Beetles) in Your Garden

These destructive insects often feed in large quantities on pumpkins, cucumbers and squashes. Here's how to get rid of squash bugs using proven organic methods.

Squash bugs are destructive insects that often feed in large quantities on pumpkins, cucumbers and winter squash.

Well known and widespread in North America, the squash bug (Anasa tristis) is a potential problem for all vegetable crops of the Cucurbitaceae family.

They are often found in large numbers and tend to clump together on leaves, vines and fruits.

Damage is caused by both nymphs and adults by sucking sap from the foliage and vines of squashes, pumpkins, cucumbers and other closely related plants.

While feeding, they inject a toxic substance that causes the host plants to wilt. When heavily fed, the leaves turn black, crisp and die.

This condition is often called "anasa wilt," which closely resembles bacterial wilt, a true plant disease.

Smaller plants may die, while larger plants often recover when feeding is stopped. Severe infestation may prevent fruit formation.

Read on to learn what the squash bug is, as well as how to identify it and get rid of it.

What is a squash bug?

Squash beetles (Anasa tristis) are insects most commonly found on squash plants (hence the name), such as squash, winter squash, and squash.

They consume the plant juices of these squashes through their piercing mouthparts. This fertilizing causes yellow spots to appear on the plants, which eventually turn brown.

They affect many members of the cucurbit family, such as cucumbers, and can cause complete plant death.

Adult squash bugs are grayish-brown to black insects that are 5/8 inches long. Squash bugs are a member of the true bug family, which also includes shield bugs and stink bugs.

Like its relatives, the squash bug takes on a shield-like shape. At first glance they may appear completely black, but their abdomen has slight variations in hue.

When disturbed, they emit an odor that has been compared to cilantro, sulfur, ammonia, or rotten meat.

How to recognize mistakes in squash?

Adults (5/8 inch long) are dark brown or gray in color, allowing them to be well camouflaged around plants.

Known as true beetles, they have a long, shield-shaped hard shell, two pairs of wings, and sucking mouthparts emanating from the tips of the head.

Spider nymphs (1/10 inch long) are voracious and feed in groups or groups. When young they are whitish-green or gray in color with red heads, legs and antennae. As they mature, they become grayish-white with dark legs.

Note: Squash bugs emit an unpleasant odor in large numbers or when crushed.

How to determine if a squash is damaged?

The pumpkin bug injects toxic saliva into the feeding area, sucking the juices from the pumpkin plants.

The first sign of squash bug damage is dark spots or yellow spots on the leaves and stems of squash plants.

Over time, these dotted marks will turn yellow and then brown. As this process continues, plants develop drooping leaves that resemble signs of bacterial wilt.

Uncontrolled populations of squash bugs may begin to feed on the fruit of squash plants as they develop on the vine.

In this case, the damage is caused by lesions that can cause the fruit to wilt quickly if the entire plant is subjected to sufficient stress.

The final symptom of pumpkin bug damage is the death of the pumpkin plants on which they feed.

The squash bug can transmit the bacterium (Serratia marcescens) that causes cucurbit yellow grape disease (CYVD), a relatively recent disease affecting cucurbit crops.

This bug not only spreads the pathogen, but also hides it inside itself for the winter, when there are no plants around.

Life cycle of the squash beetle

Adults overwinter and seek shelter under fallen leaves, vines, rocks and other garden debris.

When temperatures begin to rise in the spring (late May and early June), squash bugs emerge and fly into gardens where they feed and mate.

Oviposition soon begins and continues until mid-summer, with females laying small brown eggs usually on the undersides and stems of leaves.

The eggs hatch after one to two weeks, and the young nymphs quickly disperse to feed.

Nymphs go through 5 instars and take up to 6 weeks to develop into adults. Usually there is one generation per year.

Note: Due to the long period of oviposition, all stages of development of this garden pest occur throughout the summer.

How to prevent squash

Squash insects can be real pests in the garden, but there are ways to prevent infestations.

Here are some tips and tricks to help prevent squash bugs in your yard:

Varieties resistant to plants

If available, plant resistant varieties. Butternut, Royal Acorn and Sweet Cheese varieties are more resistant to squash insects.

Try companion planting

Companion planting can be useful in repelling squash insects. Try planting nasturtiums, catnip, garlic, onions, radishes, marigolds, calendula and tansy around plants that are commonly infested by squash bugs.

Rack for your zucchini and melons

Squash bugs prefer to hide among plants on the ground. Another effective way to repel squash bugs is to trellis the plants rather than allowing them to spread out.

They are less likely to hide in a rising grate than in a squash mound or patch.

Use Beneficial Insects

The parasitic tachinid fly Trichopoda pennipes is the most important beneficial insect for squash bug control.

This fly lays about 100 eggs on the undersides of nymphs and adults of squash beetles. When the eggs hatch, the larva enters the squash beetle's body and feeds on its innards before emerging from the beetle's segments.

As they emerge, these larvae kill squash beetles, making it possible to rid the garden of these pests. It works best when parasitizing nymphs rather than adults.

Include plants in your garden that attract this species, rather than just introducing it.

Tachinid flies include cilantro, dill, fennel, parsley, Queen Anne's lace, aster, chamomile, feverfew, bull daisy and Shasta daisy.

These flies are also attracted to weeds such as sweet clover.

Watch out for squash beetle eggs

The most effective method to prevent infestation is to check your squash plants every few days for squash beetle eggs.

Look for eggs by turning over the leaves. The eggs of squash beetles are small, shiny, oval-shaped, and copper-colored.

Crush or scrape them into a bowl of soapy water and throw them away if you see them.

Use row covers

Floating row covers are one of the most effective ways to control squash insects. They do not release adults at the beginning of the summer breeding season.

This prevents future generations of squash from feeding and laying eggs. Make sure the row cover is securely attached to the soil to prevent moisture penetration.

Floating row covers (Harvest-Guard®) are extremely effective when placed on seedlings and left in place until the plants are old enough to withstand the damage.

Researchers at Iowa State University have found that mulching with newspaper and hay before covering gardens in tight rows reduces weeds and pests.

How to Get Rid of Squash Bugs

If you have an infestation of squash bugs in your garden, there are a few things you can do. Here are all the ways to effectively get rid of squash bugs:

Pick and drown

If only a few plants are affected, collect all stages by hand from the undersides of the leaves.

Drowning bedbugs in soapy water is the easiest and fastest way to get rid of them. A simple bucket partially filled with water and dish soap will be your next best friend in controlling these pests.

Carry this bucket with you when you look around your garden every day. You can get rid of squash bugs by cutting or breaking off the insect-covered leaf. Alternatively, just submerge them in water and let them sink.

Once they are dead, you can safely dispose of the water without fear of them coming back to life.

Use boards as traps

Place boards or shingles on the ground near the host plants. Used as night cover, they make excellent traps for morning collection.

To do this, take several boards and place them around the base of the plants. At night, squash beetles crawl under boards in search of shelter.

Early in the morning, take each board and manually remove the bugs from the garden or knock them off the board and drown them in a bucket of soapy water.

Try diatomaceous earth

Diatomaceous earth does not contain toxic poisons and acts quickly upon contact. Lightly and evenly dust the crops where pests are found.

Apply neem oil

Organic insecticides are more effective against nymphs than adult bedbugs when it comes to pesticides.

This is due to the fact that egg masses and bugs collect near the crown of the vine and are difficult to reach with sprayers.

One of the most effective organic sprays is neem oil. Make 2-3 applications of neem oil at intervals of 7-10 days.

This organic insecticide works in a variety of ways, providing broad-spectrum control against most insects that harm your garden. The best part is that it is non-toxic to honey bees and many other beneficial insects.

Use insecticide

If pest levels become unbearable, spot treat with a fast-acting organic insecticide. For best results, apply to the undersides of leaves and deep under the plant's canopy where insects hide.

Try rotary machining

Rototill or dispose of infested crop residues soon after harvest to reduce the number of overwintering adults.