5 Common Pests That Bug Squash Plants and How to Stop Them

By Bethany Cihon

Squash plants are susceptible to various pests that can destroy your entire crop if you don’t stop them ahead of time. While squash borers might be the most common, that doesn’t mean they’re the only one – if only! Instead, if you opt to add some to your garden beds, you’ll need to be ready to prevent and combat these common pests that bug squash plants. 

Paying attention to your garden is key. It’s also smart to know what are the most common pests, so here’s what you need to know. 

The Squash Plant Family

All squash plants belong to the cucumber family, which is known as the Cucurbitaceae family. It’s one of the largest and most prolific families that grow in your garden each year, but they’re all vulnerable to the same pests. 

Members of the squash plant family that you need to protect include:

• Cucumbers
• Summer Squash
• Zucchini
• Winter Squash
• Pumpkin
• Gourds
• Watermelon
• Cantaloupe
• Luffa

Prevention is Key

The best defense against pests is prevention; you need to do everything you can to stop the pests from invading your garden. It’s significantly easier to work on prevention than trying to handle a massive infestation.

But what can you do to prevent pests from finding your squash plants? Here are a few suggestions to try.

Always practice crop rotation. 

As a small gardener, it’s easy to brush off the concept of crop rotation and assume it’s meant for large-scale farmers. Your assumption would be wrong, and you’ll do an injustice to your garden if you fail to use crop rotation techniques.

Some pests, such as vine borers, can continue to live in the soil throughout the winter. So, if you plant your squash in the same soil each year, they’ll continue to infest your plants, killing them. Plant a crop that is resistant to these pests in that area. 

Use row covers when you transplant seedlings.

Keep row covers over your transplants until the flowers appear. At this point, pollinators need access to the plants, so it’s better to remove them. This can prevent pests from laying eggs on or near your squash plants. 

Check weekly for signs of pests or pest damage. 

If you have to battle pests on your plants, it’s best to check them early. A small amount of pests is easier to handle than a large infestation, so take time each week to inspect your plants. Make sure to look at the underside of the leaves. 

Attract beneficial insects.

Beneficial insects can control all pests. They prey on the pests that want to cause damage to your garden plants. 

5 Common Pests That Bug Squash Plants

Squash Vine Borers 

One of the most problematic pests is the squash vine borer, typically just called a vine borer. They hatch out of their winter cocoons while still in the soil. The moths lay their eggs around the stem, close to the soil line.

These little pests can cause some severe damage. At first, you might notice eggs laid on the stem near the soil line and a small hole in the stem. Those borers will soon eat through the stem of your plant, and the entire plant wilts and dies.

These can be some of the most problematic pests to deal with because they’re underground and inside your plants rather than on the leaves. You might not catch the problem until its too late. 

So, how do you fix a squash vine borer infestation?

One thing that you can do is inject Bacillus thuringiensis (BT) into the stem, which will kill the larvae. You can find BT at most gardening centers or purchase it online. 

Another option is to use a sterilized knife to cut above the entry hole and remove the larvae by hand. Then, bury the damaged stem; it should create new roots and recover despite the damage. 

Since vine borers overwinter and live in the same garden beds in the following year, you need to remove and burn all infected plants at the end of the year. Never compost the plant material! 

Squash Bugs

No squash plants are safe from squash bugs. The adults and juvenile forms suck the plant’s sap and juices, damaging it and reducing the harvest. 

Squash bugs lay their bronze-colored eggs on the leaves’ underside, typically up to 20 eggs at a time. If left to hatch, they’ll emerge and start to suck and chew on the squash leaves, eventually causing the plant to wilt. 

How to fix a squash bug infestation

If you find the eggs on the leaves’ underside, squishing them with your hand is the most efficient way to get rid of them. It takes about a week for eggs to hatch, so you need to inspect the plant to find them before they hatch consistently.

If you miss them as eggs, the nymphs are pale green, quickly becoming darker as they mature. You have to handpick all stages of squash bugs from the plant’s base and on the underside of the leaves. Once you pick them off, put them into a bucket of soapy water. 

Another option is to spray your plant with neem oil. The odor is offensive to adult squash bugs, and if they eat a leaf covered with neem oil, it prevents them from reproducing. However, neem oil works slowly, especially on adults which are harder to kill when compared to the nymphs. 

You can also coat the leaves with kaolin clay, creating a physical barrier to stop eating your leaves. However, it washes off in the rain, and you’ll need to reapply often. It’s not an efficient choice if you have a large garden full of squash plants, but it’s a good choice if you only have a few. 

Aphids

These are the most common garden pests that bother nearly every veggie crop possible; squash are far from immune. 

Aphids are sap-sucking pests that attach to the underside of the leaves on your plants. They’re tiny, typically only ⅛ inch long at the adult stage, so they can be hard to spot. These pests also vary in color, coming in black, red, green, yellow, pink, or brown. 

Finding a single aphid wouldn’t be worrisome, but they tend to appear in large groups that quickly multiply. When they pick a plant to invade, they can stunt and damage plants, and they multiply fast. A female can create 12 offspring per day, and the eggs overwinter, hatching in the spring. 

What can you do to get rid of aphids?

Typically, the earlier you handle the problem, the better. Use your hose to blast them off the plant, but keep an eye on your other plants. They tend to jump ship and go to another plant. 

If that doesn’t work, encouraging beneficial insects to invade your garden is a great practice. Ladybugs, lacewings, and parasitic wasps are natural enemies of the aphids. While you can buy helpful insects, adding nectar-filled flowers, like bee balm or black-eyed Susans, should do the job to attract them. 

Worse comes the worse; you can use neem oil or insecticidal soaps. Spray the top and bottom of the leaves and repeat the application every 1-2 weeks.

Cutworms

Cutworms are little larvae that like to come out and play at night, destroying your crops. The adult forms aren’t damaging to your garden, but the cutworm larvae can chew through the plant’s stems and kill them. The damage can happen quickly, within a 24-48 hour period. 

Cutworms look like fat caterpillars that are either black, brown, grey, or dark yellow. Some have dots, while others have stripes, and all measure about two inches long. 

What can you do if you have cutworms

Planting sunflowers around the perimeter of your garden acts as a trap crop; cutworms love sunflowers. However, if you do this, you’ll need to go pick them off daily, or you’ll end up with an active population of cutworms. 

Another solution is to create a DIY collar around the base of your seedlings. The easiest solution is to cut a toilet paper roll lengthwise and dig it down about an inch around your plants. Doing this creates a barrier that stops the worms from accessing the stem of your plant. 

Cucumber Beetles

Just because they’re called cucumber beetles doesn’t mean that they won’t infect your zucchini plants – they will. Cucumber beetles look similar to ladybugs, but they’re yellow with either black dots or black stripes. The yellow makes it easy to spot.

One of the main problems with cucumber beetles is that they spread diseases as well, including bacterial wilt, increasing the likelihood that your plants will struggle or die.

So, what do you do if you have cucumber beetles?

You can use kaolin clay products to create a barrier layer, making it harder for cucumber beetles to feed on your plants. Another option is to spread straw mulch over your garden beds because it makes it harder for the beetles to move around. At the same time, wolf spiders are hunting spiders, and they use garden mulch to hide. Wolf spiders prey on cucumber beetles, so it’s a win-win.

You also can try companion planting, which is when you add flowers and other crops in the same garden bed as your squash plants. Planting broccoli, nasturtiums, or radishes alongside your squash plants can deter cucumber beetles. 

Final Thoughts

Squash plants are vulnerable and susceptible to various pests. Gardeners need to pay attention to their garden and watch for any infestations. The sooner you take care of pests, the less damage they’ll do to your plants. Make sure you know the most common pests that bug squash plants.