Nine Vegetable-eating Insects that will Kill Your Garden
You’re not the only one who wants to eat the bounty from your gorgeous outdoor garden. There are plenty of critters at ground level looking to beat you to it. Kate Van Druff identifies nine vegetable-eating insects and provides some ideas on how to eliminate them.
You’ve nurtured your plants since they were tiny seeds or chose them one by one at your favorite gardening center. You gave each plant a place to grow, cleared away any weeds, and offered ample water and compost or plant food as needed. Your efforts created a wonderful growing environment, that is, until vegetable-eating insects found their way into your garden space.
Insects can be tricky to get rid of at times. Here’s a breakdown of some of the most common veggie-eating insects and what you can do to stop them in their tracks.
Squash Vine Borers
Appearance: As an adult, this pest is a wasp-like moth with a black body and orange or red markings. The larvae are fat and white with a brown head, while the eggs are small, brown, and oval.
At Risk: All squash plants, gourds, pumpkins, and zucchini may face an untimely demise due to these pests.
- Wilting leaves are a common symptom.
- Holes at the base of the plant may point to borers.
- Sawdust-like droppings may appear on plants with a green or yellow-orange hue.
Interesting Fact: This pest burrows inside the stems and vines of the plant.
- Cut a slit in the stem of affected plants and remove larvae by hand.
- Insert a thin wire through the stem to kill any larvae inside.
- Try yellow sticky traps for the adult moths.
- Cover up your plants with row covers.
Appearance: Tomato hornworms have thick, green bodies with black and white striping and a blue horn.
At Risk: Tomatoes are their favorite, but these pests also gobble up peppers, potatoes, and eggplant.
- Larvae may leave behind dark green droppings.
- Missing stems and other damage may indicate a Tomato hornworm.
- Fruit may display more blemishes than usual.
Interesting Fact: Tomato hornworms can be up to five inches long — quite a startling length.
- Handpick these caterpillars out of your garden.
- Choose an insecticide that works for your garden space.
- Till your soil before and after the growing season to wipe out any of the larvae in there.
Appearance: As the larval stage of butterflies and moths, caterpillars come in a wide array of colors with three true legs and several abdominal prolegs, anal prolegs, and other structures.
At Risk: Kale, cabbage, broccoli, cauliflower, and collard greens seem to entice hungry caterpillars, as does corn, beans, carrots, radishes, peppers, and sweet potatoes, to name a few. Vegetable seedlings and juvenile plants may also suffer.
- If leaves look like Swiss cheese, you might have a caterpillar problem.
- Ragged leaves may hide caterpillars on top or underneath.
Interesting Fact: Moth caterpillars account for the majority found in vegetable gardens.
- Remove caterpillars on a case by case basis and place them in soapy water or squish them.
- Cover crops that don’t require pollination with fabric or row covers.
- Apply an insecticide that is safe for edible plants.
Appearance: Hailing from Asia, brown marmorated stink bugs are varying shades of brown adorned with markings in black, gray, blue, off-white, or copper. While their backs look like shields, they do have wings and can fly, and they have antennae with alternating bands.
At Risk: Various fruit and vegetable plants fall prey to stink bugs, including green beans, soybeans, squash, zucchini, tomatoes, peppers, okra, sweet corn, and eggplant, among others.
- Fruit or vegetables get “cloudy spots” — white or yellow superficial spots.
- Bean pods and okra may develop wart-like textures or pimples.
- Leaves may wilt, roll, or show signs of stunted growth.
Interesting Fact: True to their name, stink bugs have glands that allow them to release a pungent odor as a defense mechanism when they feel threatened, particularly when they feel pressure squeezing on them. For this reason, many people avoid squashing them to kill them.
- Spray mineral clay like kaolin clay to repel stink bugs.
- Try pheromone sprays to lure the bugs away from your garden and to a different part of the yard.
- Increase the population of beneficial bugs in your garden to combat the stink bugs. This could be praying mantises, lacewings, ladybugs, or spiders, among others. Birds and toads can also help.
- Plant decoy plants to trick the bugs into leaving your actual crops alone.
Carrot Rust Fly
Appearance: Carrot rust flies tend to be greenish-black with a metallic sheen and a slender body. The larvae are maggots that appear yellow or creamy white.
At Risk: These pests typically go straight for their namesake, but may also attack parsnips, celery, and parsley. The roots of the plants usually get the worst infestation, with the maggots (larvae) building tunnels underground to feed on the roots and get into the plants.
- You may see root damage, a common hallmark of destruction by the carrot rust fly.
- The carrots may change color to more of a dark, rust-red color.
- Rusty brown blemishes appear on the carrots themselves.
- The maggots eat the fine roots and tunnel into the main carrot, which may be deformed.
Interesting Fact: The carrot rust fly maggots’ excrement gives the pest its name, as the tunnels it digs in the carrot take on a rusty hue.
- Rely on crop rotation. Avoid planning back-to-back seasons in the same soil when you’ve noted a carrot rust fly problem.
- Try trap crops planted in the previous year’s beds to divert pests from the new crops.
- Time your seed-sowing to avoid the time when parents will be looking to lay eggs.
- Use a floating row cover to protect crops.
- Harvest earlier in the season when possible and remove all carrots before winter.
Appearance: These pests are green, velvety larvae with light yellow striping.
At Risk: Watch your cabbage, kale, cauliflower, and broccoli for signs of damage as these are cabbage worms’ favorite crops.
- Cabbage worms eat away at leaves until they’ve left many holes.
- Sometimes the plants are left with just the stems and veins.
- You might also find fecal residue or stains.
Interesting Fact: Cabbage worm eggs are so small that you may not detect them upon investigation.
- Remove the eggs if you can find them.
- Spray the leaves with water and sprinkle cornmeal on top. This technique causes the pests to swell and die when they eat it.
- Use pest control products Bacillus thuringiensis var. kurstaki.
(Read also: Getting Rid Of Bad Bugs with Beneficial Insects)
Appearance: Don’t be fooled by their simple appearance — leaf miners look like common black flies. The white or yellow-white larvae are the ones that eat the plants though, burrowing between the upper and lower layers of the leaves.
At Risk: Spinach, chard, and vegetable plants grown for their foliage are in the greatest danger of leaf miners.
- Patterns of yellow squiggly lines appear in the leaves.
- Blisters and other blemishes may bedeck plants.
- Fecal matter may contaminate leaves intended for harvest.
Interesting Fact: Because the leaf miners dwell inside the plant leaves, they are often difficult to kill with chemicals unless you get the timing right.
- Introduce beneficial bugs to decimate the leaf miner population.
- Spray the leaves with pesticide once tiny black flies emerge from the leaves. You can monitor this by putting samples inside a zipper-seal baggie.
- Look into neem oil to naturally reduce the number of larvae.
Appearance: This brown or gray bug tends to be about a half-inch long with orange stripes on its abdomen. The nymphs have gray bodies and black legs and like to gather under the leaves.
At Risk: Plants in the cucurbit family are most at risk with squash bugs, including cucumbers, squash, zucchini, and pumpkins.
- Yellow and brown spots appear on the plants from the sucking.
- Wilting leaves due to a lack of nutrition may also occur.
- Leaves may become crisp and turn black, or they may become ragged, ravished with holes.
Interesting Fact: Squash bugs inject toxins into the vegetable plants and proceed to suck out the sap. They can be very difficult to kill.
- Tackle the pest problem during the nymph or egg stages for best results.
- Remove eggs from the undersides of leaves and dispose of them.
- Apply appropriate insecticides during the egg phases.
Appearance: White and C-shaped, grubs are the larvae of Japanese beetles, June beetles, and others that tend to appear seasonally. If you have one of these pests, it’s likely you may have both life stages.
At Risk: Grubs eat the roots of grass as well as fruit and vegetable plants. Seedlings and transplants are at the greatest risk.
- Multiple grubs appear when digging in the same square-foot area.
- Your yard is a favorite digging site for birds, raccoons, and other wildlife.
- Your lawn peels away easily or the ground feels spongy.
Interesting Fact: Grubs are a food source for birds, skunks, raccoons, armadillos, and moles.
Fight Back: Eliminate the grubs before they hatch.
- Treat your lawn with a grub control product in the spring or early summer to reduce populations.
- Feed and water your garden and lawn as appropriate to your region, allowing less damage to show.
- Apply the naturally occurring bacterium, milky spore, to your vegetable garden or lawn. It is not a chemical compound and is safe and harmless to edible plants.
- Control beetles as well to decimate the grub population in your yard.
These are just a few of the many vegetable garden pests out there. What works to get rid of one may not effectively remove another from your planting habitat. It may take some time and effort to get a handle on your garden pests, but it will surely be worth it in the long run.