Even the most experienced gardeners have to deal with garden insects — especially in the summer months. Learning how to identify and control these common garden insects is paramount to having a successful growing experience. From aphids to garden slugs to tomato hornworms, we’ve assembled a guide to help you identify garden bugs that might rear their head this season.
Here are the 10 most common garden insects & how to control them, expertise courtesy of Lula Weller, our Grow Pro Partner Manager.
Not all insects are bad. Have you ever seen what a lady bug’s larvae looks like? They look like dangerous alligators to the unfamiliar eye, but they are on your side, eating away at the aphids in your garden. I like to know there is a natural balance in my garden. Properly identifying both the beneficial insects and the pests you have will help you make the right decisions about applications.Lula Weller, Grow Pro Partner managerLula Weller, Grow Pro Partner manager
1. Tomato Hornworms
You’ll know these garden pests from the soft horn that protrudes from their posterior. Green with white strips or Vs on their body, these bugs love tomatoes, eggplants, pepper, etc. You’ll know they’ve infested because they leave dark pellets of poop behind — generally on leaves towards the top of the plant.
To control them, simply handpick them daily. (Sprays are an option, but usually less effective than handpicking.) Be careful: don’t destroy any hornworms that have the white, rice-like cocoons of parasitic wasps hanging from their backs.
2. Squash Bugs
These guys are the hardest to control of all garden pests.
About 5/8 inches long with dark brown, oval-shaped bodies, they generally group together. They’ll chow down on any member of the cucumber family, which is most vining plants. You’ll be able to tell squash bugs are lurking by because leaves will turn a mottled yellow, before becoming crispy and dying.
To avoid them, use trellises and floating row covers. As you grow, check the underside of leaves daily and remove any egg clusters you find with a piece of tape.
The most famous of all garden pests.
There are nearly 4,000 types of aphids that will target your plants.
Tiny pear-shaped insects in green, yellow, red, gray, or black, these bugs make leaves curl and ensure buds don’t open — especially on tomato, kale, and lettuce plants. Even worse, their sugary byproduct attracts ants.
To remove them, spray aphid clusters with a hose or target with insecticidal soap.
Ladybugs and lacewings will also eat aphids.
Whiteflies are tiny little triangular winged bugs you’ll find living underneath your garden leaves. If you disturb them, they’ll frantically fly up in a big white cloud — that’s how you know you have them. (Be warned: it is a kind of horrifying experience.)
These garden pests absolutely love tomatoes, but you can also find them around peppers, citrus, etc. They suck plant sap and damage leaves.
Use ladybugs or lacewings to control whiteflies. Horticultural oils, soaps, or bioinsecticides with specific fungi to target whiteflies are also good options for getting rid of these pests.
5. Cabbage Worms
At one inch long, cabbage worms are light green and sport a faint yellow stripe along their back. Adults are white butterflies with up to four black spots on their wings. They’ll eat kale, kohlrabi, radishes, and more by chewing holes in leaves.
To prevent cabbage worms, hang birdhouses nearby! To control them, handpick these garden pests.
For additional treatment, try Bt-based insecticides or hot pepper wax.
6. Colorado Potato Beetle
Adult potato beetles are about a third inch long, round, and host black and tan striped wing covers. All members of the tomato family are in trouble: eggplants, peppers, tomatillos, etc. These common garden insects skeletonize foliage all the way down to leaf veins and make their home towards the tops of plants.
In the early morning, shake adult beetles from plants into soapy water. Do this regularly to ensure you avoid infestation!
7. Cucumber Beetles
About a 1/4 inch long with bright yellow spots or stripes, these bugs snack on melons, cucumbers, squash, or beets. Identify them by the small ragged holes in leaves and flowers they leave behind.
To avoid cucumber beetles, cover with floating row and clean up all garden debris. To remove them, either handpick them or use a sinusoid-based organic pesticide (neem bases also work).
Cutworms are nocturnal brown/gray moths as adults, but the larvae are 2 inch long caterpillars that curl into a tight C-shape when distressed. Anything’s game to these guys, but their favorites include tomatoes, broccoli, and kale. They chew outer stem tissue — you can tell by the wilted or severed seedlings.
To get rid of cutworms, bait with cornmeal or wheat bran. They’re attracted to the scent, but they can’t digest the cornmeal and will die.
9. Garden Slugs
Garden slugs are the most prolific and common garden insects. They feed on almost anything! Slugs leave clues everywhere — identify them by their slimy trails and the holes in leaves.
Control them by placing boards or burlap bags throughout the garden overnight. Before day breaks, slugs will crawl beneath the boards, and you’ll be able to scrape them into a bucket of soapy water.
PRO TIP: Water only in the morning!
10. Flea Beetles
These are very small black or brown beetles that hop like fleas. You’ll find them around radishes, tomatoes, and eggplants, and you’ll be able to identify them by the small round holes in plant foliage.
Place yellow sticky cards above plant tops to lure and trap adults. For products, use hot pepper wax or neem and sinusoid-based products.
Ultimately, garden insects are unavoidable, but if we can properly identify them, we’ll have better luck controlling them. If you’re having problems with one of these bugs (or any bug), contact us! We’ll happily help.
Tomatoes are a hotspot for many of these pests. If you’re worried you might need to let a plant go due to pests or other causes, check out Brie’s Tips on when to know if your tomato plant has died.