Garden Insect Pests

by Juanita Schulze

Garden insect pests can be controlled by attracting beneficial insects to your garden area. This is what we do to keep our plants healthy. We try not to use any insecticides at all, but sometimes, you have to in order to save your plants. When that happens, we use the organic insecticides listed at the bottom of this page.

Garden pests are your enemies. It is important to know who they are and what they do. You definitely want to attract beneficial insects to your garden if you have any of these horrible creatures attacking your plants. That is always the best solution.

There are also a number of organic insecticides and fungicides. I believe that Safer puts out a three-in-one for insects, fungicide and mites.

You can also use orange oil. Mix this at one ounce to one gallon of water. Or mix it in with your organic fertilizer. Medina Agriculture has orange oil and many organic fertilizers.


Aphids are tiny brown, black, or green bugs that suck plant sap from leaves, causing them to drop. They secrete liquid on the leaves that promotes powdery mildew which promotes disease on the plants. Aphids enjoy most flowers, fruits and vegetables, trees, and ornamental plants. Use hot pepper spray and insecticidal soap.

Pictured above is our squash plant that had powdery mildew after aphids attacked it. Liquid Copper took care of the problem.


Armyworms are caterpillars before turning into moths and are found in North and South America. They eat everything so your garden will be destroyed if you have enough of them. They are yellow to gray with black stripes and should be destroyed on sight. They cannot survive freezing weather which is nice.

Cabbage Maggots

The larvae (babies) are tiny white maggots and they grow into quarter inch gray flies. They enjoy any member of the cabbage family. The maggots tunnel into the roots of the cabbage plants The best prevention is to use floating row covers. Sprinkle the roots with red pepper dust.


Caterpillars chew on fruit and vegetable leaves and tunnel into the produce and dirty the produce with their droppings. Most of us know what caterpillars look like because they turn into butterflies. There are actually several kinds in different colors who turn into things other than butterflies as well. They are found throughout North America.

Colorado Potato Beetles

The larvae are orange grubs and the adults are yellowish-orange beetles with 10 black stripes on their wings. Their eggs are yellow ovals, laid in upright piles. They enjoy feeding on tomatoes, potatoes, eggplant, and petunias. (What do those four plants have in common with each other?) They are found throughout North America.

Corn Earworms

Corn Earworms love to eat corn. When the same larvae bug eats tomato plants, it is called the Tomato Fruitworm. When it eats cotton, it is the Cotton Bollworm. The larvae is aggressive and will bite. It even eats other larvae. I have seen them destroying corn. Flower bugs will put an end to them.


Cutworms are fat one inch bugs that are gray or black. They chew through the stems next to the ground, destroying small plants before they get a chance to grow and produce. Cutworms do the most damage in May and June. They are found throughout North America.

Flea Beetles

Flea beetles are found throughout North America and enjoy most vegetables. The adults chew holes in the leaves of the plants so the leaves look lacy. The larvae chew the plant roots. Floating row covers are a good prevention.

Gypsy Moths

This moth, as a caterpillar larvae, destroys hardwood trees in the Eastern United States. It came to the United States in 1869 from Europe. (Thank you, Europe!) The eggs are laid on cut firewood and is transported on the cut wood. Firewood should be used locally to stop the transport of this moth that moves about 13 miles across the United States per year.

Japanese Beetles

The larvae are fat, white grubs with brown heads and the adults have bronze wings with bodies that look metallic blue or black. They are found in all states east of the Mississippi River and enjoy flowers, vegetables, and small fruits. The adult garden insect pests eat off all of the leaves and the larvae eat the roots.

Mexican Bean Beetles

The larvae are dark yellow fat grubs and the adults are 1/4 inch yellowish-brown, oval-shaped with 16 black spots. They enjoy chewing on the leaves of soybeans, snap beans, lima beans and cowpeas. They are found in Texas, Arizona, Colorado, Utah, Nebraska, and most states east of the Mississippi River. Spraying the affected plants with insecticidal soap is good to keep these garden insect pests away.


The female scales look like bumps on the plants and the males fly. The larvae are tiny and soft and crawl. All of them suck the sap out of the plants, turning them yellow and then killing them. They love fruits, trees, ornamental shrubs and indoor plants. These garden insect pests are found throughout North America.


A slug is a mollusc which means there is no shell. Salt melts them and it is kind of cool....if you don't think about it too much. They enjoy eating flowers, leaves on plants, and strawberries.


Like slugs, snails are nasty. Salt will melt them under the shell. They will destroy plant leaves. We get a lot of them in Texas.


A sowbug is a woodlouse and is known by many other names as well. They enjoy feeding on strawberries and tender seedlings.

Spider Mites

These garden insect pests live on the undersides of plant leaves and eat the leaves, destroying the plants.

Squash Bugs

These bugs destroy squash plants, pumpkins, gourds, cucumbers, watermelons, and luffa plants. They are part of the Coreidae family.

Tarnished Plant Bugs

These nasty bugs move fast and the adults are green or brown with wings that have yellow triangles with black trim. The babies do not have wings. They attach fruits, vegetables, and flowers. They suck the juice out of the plants, causing them to wilt and stop growing. They are found throughout North America.


Thrips are tiny and thin with wings that are fringed. They are also known as corn lice, storm bugs, thunder-blights, thunder-flies, thunder-bugs, and storm flies. Thrips feed on plants and animals, sucking them dry. These garden insect pests are brown and look like cigars with legs.

Greenhouse White-flies

White flies are small bugs that cover the stems of plants, especially tomato plants, that are also known as glasshouse. They spread disease and suck the nectar out of the plants.