Types of Plant Pests in North America

Travel throughout North America, and you’ll experience several types of climates. You’ll also encounter many different types of plant pests.

Depending on where you live, some plant pests may be more common than others. Understanding which pests are common to your area can help you identify the warning signs in your garden of a plant pest problem.

Keep reading for a complete outline of the most common types of plant pests throughout North America.

What are Plant Pests?

There are both indoor plant (houseplant) pests and outdoor plant pests. The indoor bugs will attack the potted plants you have around your home, while the outdoor pests will attack your vegetable gardens.

Plant Pests Damage

Depending on the types of plant insects you find in your vegetable gardens, the damage can be minuscule to drastic.

It’s much more common to experience outdoor plant pests than indoor ones. Plant pests will eat your plants, causing them to die, or spread diseases among them.

Unfortunately, most people don’t realize they have a plant pest problem until their plants are already greatly suffering.

Top 7 Types of Plant Insects to Watch Out For

Squash Bugs

Squash bugs, AKA Anasa tristis are flat in shapes and are dark brown or black. They are sometimes mistaken for stink bugs, but they are slightly larger and broader.

Squash bugs like to collect at the base of plants, or lay eggs on the undersides of leaves that have died. They have sharp mouths that allow them to pierce plants and suck plant sap. This causes yellow spots to occur on leaves, which then wilt, blacken, and fall off.

A squash bug lays eggs that are long and yellow. This species gets their name from their love of squash. You will typically find a squash bug on different types of squash, zucchini, and pumpkins, although they also enjoy melons.

Squash bugs are found throughout the United States and in southern Canada.

Watch this video to learn how to control squash bugs

Spider Mites

Spider mites are tiny (approximately 1/50 inch long) in size and usually reddish-brown in color as an adult. These small creatures aren’t technically an insect but are a type of arachnid, sharing the same classification as spiders, scorpions, and ticks.

Spider mites live in large colonies and like to collect on the underside of leaves. When there is a large colony present, there may be a presence of webbing on the plant.

Spider mites feed by piercing leaves and sucking in the plant fluids. These bites show up as light dots on the leaves. After spider mites feast on part of the plant, the leaves of the plant will eventually turn yellow and may dry up and fall off. Spider mites love choosing strawberries, beans, tomatoes, melons, and eggplants as their hosts.

Watch and learn how to control spider mites

Spider mites can be found all over the United States, but they especially thrive in warm, dry climates. Different species are more common in certain areas.

For example, the spruce spider mate is often found in eastern U.S. states and California, while the two-spotted spider mite is more common in northern regions of the United States.

Tomato Hornworms

The tomato hornworm is the larvae stage of the Five-spotted Hawk Moth, AKA the Manduca quinquemaculata.

Tomato hornworms are large in size (about four inches long) and green in color. They have small posterior horns on their head. Their natural-green hue allows them to blend in easily with their environment, making them incredibly hard to detect.

Hornworms love the leaves of plants including tomatoes, as well as pepper plants, potatoes, and eggplants. And, their natural large size means they can do damage to a vegetable garden quite quickly.

These plant pests are most common in the northern United States.

Check out this quick video to learn how to control tomato hornworms

Flea Beetles

Flea beetles are miniature versions of the full-sized beetles. They’re small (about ⅙ inch long), shiny, black or blue, and they jump around like fleas.

They like to attack many different kinds of plants but especially love vegetable plants.

When they feed on foliage, they produce small holes in the leaves of plants. Flea beetles lay their eggs at the base of plant stems, and when larvae hatch, they feed on the roots of plants.

Flea beetles are most typically found in the eastern states of the U.S.A.

How to identify flea beetles and get rid of them

Cabbage Worms

Cabbage warms are bright green, have skin that looks like velvet, are hairy, and have a row of light spots running down their back.

These pests get their names from their love of cabbage and plants of the cabbage family (kale, cauliflower, broccoli). When they eat at a cabbage plant, these worms bore directly into the head of the plant. As they eat through plants, they create large, irregular holes.

Cabbage worms are found everywhere across North America, from the southern states like Florida to northern regions like British Columbia.

Learn how to kill cabbage worms and hornworms

Cucumber Beetles

Cucumber beetles are easy to spot as they are bright yellow with black stripes or spots. These pests love to feed on the leaves on plants, soft fruits, shoots, and blossoms.

As the name implies, cucumber beetles love cucumbers, as well as variations of squash, melons, and gourds.

The larvae, which are thin and white in appearance, feed on the roots of plants. This leaves plants susceptible to wind damage. The pests also transmit bacterial wilt they eat through leaves.

Bacterial wilt is quick to spread, and while it may not kill plants, it can cause the loss of flowers and fruits. In particular, bacterial wilt is especially hazardous for cucumbers and muskmelons.

Cucumber beetles are most commonly found throughout the United States and Canada, east of the Rocky Mountains.

Learn how to stop cucumber beetles from eating your garden

Fungus Gnat

Fungus gnats are small insects that are about the size of a fruit fly. The adults are grayish-black in color and have translucent wings. Fungus gnats have long legs and long antennae, which makes some people confuse them for mosquitoes.

Fungus gnats are attracted to the moisture of potting soil and can lay up to 200 eggs at once on a soil surface. These eggs only need three days to hatch into larvae and burrow into the ground. 

The larvae feed on fungi and decaying plant material, mature into adult gnats within two weeks, and repeat the entire process. Fungus gnats only live a week as an adult, but their ability to breed in large amounts means an infestation can occur quickly.

Fungus gnats also spread a type of plant pathogen that causes damping-off and the death of seedlings.

There are over 600 species of fungus gnats found all across the United States.

Check out this video on Fungus Gnats to learn how to identify them and get rid of them