What’s Eating My Cabbage? 15 Common Cabbage Pests

You’re probably growing cabbage because you enjoy eating it. And if you’ve ever tried growing this crop before, you probably realize that a lot of garden pests also enjoy eating cabbage. This article explores potential culprits and how to get rid of them.

Cabbage is a member of the mustard family, often referred to as the Brassica family, or crucifers. Other familiar brassicas include broccoli, cauliflower, Brussels sprouts, kale, collards, turnips, mustards, and horseradish. These are primarily cool-weather garden vegetables that love full sun and moist, rich soil with excellent drainage. 

Aphids

Aphids are ubiquitous garden pests. You’ll see them gathering in large numbers along the leaves and stems of many garden plants. They are also fond of cabbage and congregate along the veins of the outer leaves.

These soft-bodied insects are clearly visible to the naked eye. They may be green, gray, white, yellow, or pink. Sometimes, brassica aphids may appear green but with a white waxy or powdery-looking covering. Aphids suck plant juices and cause the leaves to become withered, curled, and weak, eventually turning yellow and brown, and finally dying. 

Use a strong jet of water from your hose to dislodge aphids. A daily blast of water is often enough to discourage aphids from coming back. You can also use insecticidal soap to effectively kill aphids, spraying it directly on groups of these pesky little insects. 

Cabbage Looper

Cabbage loopers are bright green inchworms that are a major pest of this crop’s leaves. They move by inching along because they have no legs in the middle part of their body. These are the larvae of an unassuming mottled brown-gray moth called the cabbage looper moth. The adult moth lays its eggs on a brassica plant, and a few days later, the eggs hatch into voracious little caterpillars.  

These hungry little caterpillars chew holes in the leaves and grow quickly from just a few millimeters long to about 1.5 inches long. They munch gaping holes in the leaves anywhere they can reach. A badly infested plant will have leaves riddled with many large, jagged holes.

Cabbage loopers are very common pests and the larger they grow, the more damage they cause. They will stay on your plants and eat for three or four weeks, until they are ready to pupate into their adult moth form. 

Keep an eye on your plants. If you see telltale holes and bright green inchworm-like caterpillars, you have cabbage loopers. Prevent them by protecting your crops with floating row covers; the adult moths won’t be able to lay eggs on covered plants.

Removing caterpillars by hand, BT sprays, and natural predators are effective organic pest control methods. Natural pesticides can also be used.

Cabbage Root Maggots

Cabbage root maggots are the larvae of the cabbage root maggot fly, a brownish-gray fly measuring between five and seven millimeters long. The adult fly lays its eggs in the soil at the base of a host plant. The eggs hatch and the larvae burrow into the stem and feed on the plant’s roots.

As the root maggots destroy the stems and roots, your plants begin wilting and the leaves will turn yellow. Shortly thereafter, as the larvae continue feasting on the root system, the plants will wilt severely, collapse, and die.

Floating row covers will prevent adults from laying eggs on the stems and tilling the soil after your crops are harvested will help prevent overwintering pupae from maturing. Crop rotation with non-brassica plants will also help prevent a buildup of these pests.

If you can delay spring plantings until the soil has warmed considerably, this will help kill any eggs that may be present and thus prevent infection, although your brassicas may suffer from the heat. 

Cutworms

Cutworms are very destructive, given their small size. These little caterpillars cut right through young plant stems, causing them to topple over and die. There are many species of cutworms but they all have the same method of destruction, so it won’t matter so much that you identify the species as long as you recognize your plants have succumbed to a cutworm attack.

Cutworms that attack brassicas may vary in color, but they all appear to have smooth skin and they are well camouflaged with the soil, generally with brown or gray coloration.

These are the larvae of a brown or gray moth. An adult moth can lay hundreds of eggs, either singly or in small clusters, at the base of their respective host plants. 

When the eggs hatch, the hungry larvae set to work chewing on leaves or larger plants or cutting smaller plants down entirely. Cutworm larvae feed primarily at night and hide in the soil during the day, so you may never see them, but you’ll see evidence of their chewing the following morning. 

Predatory beetles and parasitic wasps prey on cutworms but this may not be enough to curb cutworm damage. Keep your garden bed weed-free to eliminate their hiding places. If you suspect a cutworm problem, use BT to help control them. 

Diamondback Moth

The diamondback moth is found throughout North America and is a very common garden pest. The adult moth is small and slender with patterned brown markings. It lays eggs on all cruciferous vegetables, including all varieties of cabbage, collards, and cauliflower. 

Diamondback moth larvae hatch after a few days and immediately start feeding. The small, pale green caterpillars have tiny black spots on their bodies but no other distinctive markings. They rarely reach more than one centimeter long before pupating in a silky cocoon attached to the cabbage leaf. 

The larvae are small and they can cause notable pest damage, although not as much as some of the other common cabbage-feeding caterpillars. Diamondback larvae chew through layers of leaf tissue without chewing completely through the leaves. This is a distinctive difference between these and most other common caterpillar pests.

For natural, chemical-free control methods, use row covers to prevent adults from laying eggs, and hand-pick individual caterpillars. Grow cabbages interplanted with non-cruciferous vegetables and herbs to deter pests.

Practice crop rotation and include a diverse assortment of plants in your landscape to welcome a host of beneficial insects and insect-eating birds to help you control pesky insect pests.

Cabbage Webworm

Do you see plump tan to grayish-yellow caterpillars on your plants, turning them into a chewed-up mess? Younger caterpillars may be a solid tan color while older caterpillars have distinct brownish strips running laterally along their bodies.

These are the caterpillars of the cabbage webworm moth, a mottled brown moth measuring about one centimeter wide and less than two centimeters long when at rest.

These crucifer-loving caterpillars feed on cabbages, broccoli, bok-choy, collards, and turnips, to name just a few of their favorite foods. They typically chew up the undersides of leaves without breaking all the way through.

This does enough damage to cause the plants to wilt and prevent head and flower formation. Infected plants will be visibly damaged, weak, and brittle as the caterpillars chew into their veins and stems. 

These pests are very difficult to control. Since they hide out on the undersides of leaves, they will be difficult to remove by hand and insect predators are inefficient at hunting them down.

Insecticides that target caterpillars can be used to control them, but be aware that these insecticides also harm beneficial insects and pollinators so use them sparingly and carefully to target just the pests you see. 

Imported Cabbageworm

Most caterpillars that feed on cabbage are the larvae of moths. The imported cabbageworm, however, is the caterpillar of a butterfly known as the cabbage white. These white butterflies are small butterflies with white wings and distinctive black spots on each wing.

This is a common pest that’s similar in appearance to other native species of cabbage white butterflies, although the imported cabbageworm is now the most common.

These soft, green caterpillars measure up to three centimeters long. They have a slightly ridged, velvety appearance with pale yellow spots along the lower sides of the body. These caterpillars feast on your plants for about two weeks before pupating either on their host plants or in surrounding leafy debris.

If warm enough, they emerge again as butterflies within two more weeks, but later in the season, they will overwinter as pupae and emerge as adults the following spring.

The imported cabbageworm caterpillars often feed along the larger leaf veins, chewing holes along the way. Multiple caterpillars on the same leaf will quickly reduce the leaf to nothing but veins. They are happy to feed on any cruciferous vegetables and active caterpillars can easily move from one plant to the next. 

Parasitoid wasps, vespid wasps, and assassin bugs are predatory beneficial insects that attack these voracious caterpillars. Hand-picking is effective but tedious because there will often be hundreds of these little green caterpillars on your plants.

Installing floating row covers at the time of planting is very effective at keeping the adults off your plants, therefore preventing them from laying their eggs. 

Cross-Striped Cabbageworm

Cross-striped cabbageworms are a the larvae of a moth and are common brassica pests in the southeastern United States. They feed on cabbage plants, broccoli, cauliflower, and other favorite garden brassicas. You’ll notice their initial feeding damage as holes in the leaves, but as the damage progresses, the leaves may be entirely skeletonized.

You may never notice the non-descript gray-brown adult moth but the caterpillars are fairly obvious. They quickly grow from an egg up to about one-inch-long caterpillars. They have orange heads, yellowish and gray lateral stripes on their sides, and a white, gray, and yellow speckled pattern on their backs.

These caterpillars are most common with late-season crops. Prevent the adult moths from laying eggs on your plants by covering them with floating row covers. Invite beneficial insects, such as parasitic wasps, to your garden to help control caterpillar pests. Try removing individual caterpillars by hand if you have only a few cabbage plants. 

Southern Cabbageworm

The southern cabbageworm is a common pest throughout much of the southern United States, although it can also be found in more northern states. It is the larvae of the checkered white butterfly which lays its eggs on brassica crops.

The caterpillars then feed on the leaves until they reach maturity and pupate into the next generation of adult butterflies.

Southern cabbageworm caterpillars reach just over one inch in length. They are gray and yellow striped, with tiny, irregular black spots and coarse, short hairs. You’ll see the caterpillars on the leaves, and you’ll clearly see the ragged-edged holes they chew as they feed, typically only in the outer layer of leaves.

These caterpillars seem to be more of a problem for fall crops than spring crops, and they may not be a problem every year. 

Control these caterpillars as you would other caterpillar pests. Use floating row covers to prevent butterflies from laying eggs on your plants. If you just have a few cabbage plants, spend some time in your patch every day and hand-pick individual caterpillars. Attract beneficial insects to your garden that will feed upon these and other caterpillar pests. 

Beet Armyworm

The beet armyworm is a common pest, particularly in the southern United States. This is the caterpillar of the mottled brown beet armyworm moth. The adult has a wingspan of about three centimeters and a soft, fuzzy-looking pale grayish-brown body. 

Adults lay their eggs on a wide variety of garden vegetables, including cabbages and other brassicas as well as many others. Unlike many butterfly and moth species that have very specific host plants, the beet armyworm seems to eat just about anything.

Each adult female can lay up to 600 eggs, which means that you will likely have an army of hungry caterpillars feasting on your favorite garden veggies. 

The caterpillars are pale green and plump. Their smooth bodies are either all green with various green bands or they have a distinctive reddish-pink line along each side and a line of dark spots or rough ovals above the pink lines. These caterpillars feast their way through the leaves, making large irregular holes as they feed.   

Prevention is the best way to control a beet armyworm invasion, using floating row covers at the time of planting to protect your cabbage crop from adults trying to lay eggs.

Parasitic wasps and other insect predators will happily feed on these plump caterpillars. Natural and biological controls are best for these pests because they are largely resistant to pesticides, which results in the overuse of ineffective chemicals and harming beneficial insects.

Flea Beetle

The flea beetle is a small black beetle that feeds on leaves, particularly of young plants. They chew many tiny holes in the leaves and if multiple beetles are present, as they usually are, they can easily destroy seedlings before they have a chance to grow. These tiny beetles have the habit of springing from one place to another, earning them their name. 

Flea beetles don’t specialize in cabbages or brassicas, they chew up many other garden crops as well, including beans, eggplants, and tomatoes. If you have these pests in your garden during one season, you can expect to see them persist through the entire growing season, damaging multiple crops to the point of oblivion. 

These persistent pests are difficult to control but there are some preventative measures you should take if you’ve seen these beetles before. Till your garden in the fall to expose any buried insects and eggs that may be hiding in the soil.

Add beneficial nematodes to your soil to feed on the soil-dwelling beetle larvae. You can also try companion planting with mint and basil to help repel flea beetles and other pests, as well as attract beneficial insects to your garden. Pyrethrin and spinosad are organic insecticides you can use in conjunction with cultural and preventative controls.

Harlequin Bug

Harlequin bugs are destructive insect pests that feast primarily on cabbages and other cruciferous vegetables. They are prevalent throughout the southern half of the United States and can cause serious harm if not controlled. 

The black and white banded eggs are laid on the undersides of the leaves of a suitable host plant. The eggs hatch into tiny round, dome-backed insect nymphs with bright orange and black markings. At this stage, they could almost be confused with ladybug beetles.

As these insects grow, develop, and molt, their patterns change, but they all have variable patterns of black, white, and orange markings. Adult harlequin bugs are more easily recognized as a species of stink bugs with their angular bodies and bold black and red, orange, or yellow markings. 

Harlequin bugs pierce and suck the juices from plant leaves. Affected plants wilt and leaves turn yellow and brown. Plant growth is stunted and your plants may die if seriously infected. These insect pests are easily seen and you will have no trouble identifying them as the culprits. 

Control harlequin bugs by keeping your garden clear and weed-free to reduce habitat for hiding pests. Hand-pick and destroy any eggs, nymphs, or adults that you see on your plants. If damage is severe and you have a large infestation, try spraying infected plants with an insecticidal soap.

Whiteflies

There are many different species of whiteflies, but the ones most often found on cabbages and brassicas are the cabbage whiteflies. These are tiny flying insects that are, as their name implies, white.

You may or may not see these little pests but they do their fair share of damage to cabbage plants. They are most prevalent in the fall and generally limited to warmer climates where they can overwinter. 

Whiteflies suck plant juices and you may think that since they’re so small, they shouldn’t cause any serious harm, but they do. Whiteflies reproduce quickly and soon dwell on your cabbage leaves in tremendous numbers. As they suck nutrients from your plant, they deposit a sticky honeydew that attracts fungal diseases that cause further damage. 

When you buy young cabbage plants from your local garden center, check them carefully for any sign of insects, including whiteflies, before bringing them home. You don’t want to accidentally bring these pests into your garden if you can avoid it. 

Invite and welcome beneficial insects to your garden so they can prey on these and other insect pests. If you need more help than the dragonflies and ladybugs can offer, you can spray with insecticidal soap, but use this with caution as it will also harm good garden insects. 

Slugs and Snails

If you have any protected, damp hiding places in or around your garden, you probably have slugs and snails hiding out there. Slugs and snails feed primarily at night but leave telltale slime trails on the leaves and the ground around your garden plants. In the morning, you’ll see the damage they cause in the form of smooth-edged holes along the edges and the centers of the leaves. 

If given the opportunity, these slimy pests feast on cabbages, lettuce, strawberries, hosta leaves, and many other favorite garden plants.

Slugs and snails lay their eggs in the soil, usually under wet leaves, in compost piles, and under wood, stones, and garden planters. Lift any of these items and you’re likely to see at least a couple of snails hiding underneath. 

Protect your plants from slugs and snails by removing their hiding places. You can also deter them with copper edging and diatomaceous earth, although you’ll need to reapply the diatomaceous earth after rainfall. Another trick to try is setting beer traps which attract slugs away from your plants and drown them. 

Mammals

Deer, rabbits, squirrels, mice, and groundhogs eat a lot of garden plants. They may each have their favorite plants to munch and, while cabbage may not be at the top of everyone’s list, browsing mammals will probably at least taste your cabbages, especially when young and tender. 

Mammals don’t just nibble little holes in the leaves of your developing cabbage head— they eat the entire thing. In one bite. Chomp. Gone. It can be frustrating, to say the least, to be watching your plants grow, and then you notice that suddenly they’ve vanished. 

If you want to keep deer and other mammals away from your cabbages, you’ll have to plant your cabbages where mammals can’t access them. Plant your garden within a fenced area.

Use critter cages to protect seeds, seedlings, and young plants, and hope that they’ll quickly grow large enough to be uninteresting to munching mammals by the time they’ve outgrown the cage.

Frequently Asked Questions