Identifying Cauliflower Bugs: Tips On Controlling Cauliflower Insects

By: Bonnie L. Grant, Certified Urban Agriculturist

One of the most popular crop groups are the crucifers. These encompass leafy vegetables such as kale and cabbage, and flowering species like broccoli and cauliflower. Each has specific pest problems which may become issues of concern in some regions more than others. Cauliflower bugs can decimate the crop and make the flower head unfit to eat. Treating bugs on cauliflower starts with correct identification of the pest and a targeted control plan that is non-toxic and safe for food plants.

Treating Bugs in Cauliflower

Cauliflower is a versatile vegetable, delicious either cooked or raw. Common signs of an insect invasion may be holes in leaves, tracks on foliage, missing vegetation and poor vigor. Some of the larger insect pests are easy to detect but others are too small or only come out at night, and diagnosis can pose a problem. Knowing the most common cauliflower pests is a good start to vetting the problem and annihilating these annoying and destructive bugs on cauliflower plants. The most common cauliflower pests are aphids, flea beetles, slugs and snails, leaf hoppers, and several insect larva.

Sucking Insects

The one pest that is familiar to most gardeners is the aphid. These are small, soft bodied flying bugs that reduce plant health by sucking sap from leaves and stems. They also attack the succulent flower, covering it in their sticky honeydew secretion and stunting the growth of all parts of the plant. Ants may indicate their presence, since ants “farm” aphids for their honeydew.

The harlequin bug is another sucking insect. Both the adult and larval stages feed on plant sap and cause foliar death. The insect is 3/8 inches (1 cm.) long, shield shaped and has distinctive red and black spots on its back. Insecticidal soap or oil is often used in controlling these cauliflower insects.

Worms, Larva and Caterpillars

Whatever the name, the larva of many insects and moths are the most destructive cauliflower bugs.

  • Cabbage webworms are small 3/8 inch (1 cm.) long, green striped larva that spin webs.
  • Cabbage looper is one of the rampant cauliflower bugs that is light green with yellow stripes. The larva loops when it walks. This larva will make tunnels in the cauliflower head.
  • The cross-striped cabbage worm is a small gray larva with horizontal black stripes and a light green yellow mottled underbelly. Damage occurs as holes in the foliage, which can destroy the plant’s ability to harvest solar energy and diminish overall health.
  • An imported cabbage worm is green with a narrow orange stripe down the back.

Many parasitic wasps and Bacillus thuringiensis are useful to combat these pests.

Other Bugs on Cauliflower Plants

Slug and snail damage are characteristic with holes and slimy trails over the foliage. Pick off the pests at night or use diatomaceous earth for controlling cauliflower insects such as these.

Another insect that can be repelled by diatomaceous earth is the flea beetle. The small bronze to black beetle leaves holes in foliage while its larva feed on young plant roots.

Blister beetles are 3/8 inch (1 cm.) long and gray. They chew holes in leaves causing foliar death. Use pyrethrum and cultivate in spring to kill the larva.

The yellow margined leaf beetle has wings bordered by gold, but its attractive appearance belies its danger to crops. Adults and larva eat the leaves of cauliflower.

Use non-toxic safe methods for treating bugs in cauliflower to preserve the crop and retain its safety for eating. In addition to diatomaceous earth, horticultural oils and soaps and hand picking, the natural bacteria Bacillus thuringiensis is an excellent control. You may also purchase natural enemies in the form of beneficial nematodes and wasps.

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How to Get Rid of Bugs in Your Garden

Learn how to get rid of bad bugs in your garden without damaging the environment.

Insects are our friends AND our enemies in the garden. Today's gardeners know that some chemicals that eliminate bugs in your garden can also be bad for people, pets, and the environment. They're expensive, and they take time to apply.

To safely get rid of bad bugs in your garden, start with an Integrated Pest Management (IPM) approach to control threats to your flowers, trees, shrubs, and vegetables.

IPM combines cultural, physical, biological, and chemical tools to manage the garden. Begin by starting with the least toxic method, then work your way through six steps.

3. Flea Beetles

Flea beetles love to feed on young leaves and their offspring feed on plant roots. The goal with flea beetles is to deny them access to young plants. Set up garden tents for early spring and cover your newly planted seeds with floating row cover so the beetles can’t get a start.

If you find young plants with round holes in the leaves or notice small black bugs that hop when you get close, you’ve likely got a flea beetle infestation. Garlic spray will drive these creatures away, but you’ll need to reapply when their larvae hatch.

Organic Solutions for Common Garden Pests

Protect Your Garden the Organic Way

Avoiding chemical pesticides in your home lawn and garden is a great step to ensuring the health and safety of your family, pets, neighborhood, and the earth!

By the time you notice holes in leaves, weak stalks, and rotten fruit, pests have already won the battle with that plant in your garden. Understanding pests’ lifecycles and habits and using smart gardening strategies will prepare you to prevent pest damage before it happens. We have also gathered non-chemical solutions for dealing with a pest after it has already made a home in your lawn or garden.

Why is it Important to control Pests the Organic Way?

Often we react to seeing weeds or pests by immediately applying chemicals, or even apply chemicals as prevention.

Exposure to pesticides has been linked to a long list of diseases and health problems: Parkinson’s, infertility, cancer, birth defects, encephalitis, and lymphoma, just to name a few. Another problem is that the law does not require companies to test lawn pesticides with the same standards as pesticides used on commercially-grown food. Many of these contact hidden “inert ingredients” that have never been tested for possible harm. The Center for Disease Control has documented cases of farmworker illness after exposure to pesticides.

In addition to the harm they can do to us humans, pesticides contaminate the air, water, soil, plants, and animals around us. For example, many studies have proven that pesticides harm honeybees, butterflies, ladybugs (which eat lots of other pests), and fish, and that lawn chemicals seep into the water table.

Besides that, they can be expensive!

Learning to combat pests without chemicals is a great way to help your health and that of your neighbors and the environment.

An important thing to consider is that healthy organic soil is an easy way to reduce pests in the first place. Plants tend to thrive in an organically rich environment, which helps them fight off pests on their own. If you don’t already have one or more compost bins for composting at home, get one. It also wouldn’t hurt to have a compost pail to keep near the kitchen sink to collect vegetable scraps conveniently.

Orange Guard is a non-toxic organically approved bug killer. The active ingredient d-Limonene (orange peel extract) destroys the wax coating of the insect’s respiratory system. When applied directly, the insect suffocates.

This OMRI listed organic insect killer and repellent for your lawn and garden that attaches to a water hose for easy application. It kills and repels bugs.

An organic, non-toxic killer for the natural control of Japanese Beetle grubs.

More About Avoiding Chemical Pesticides

Links to more information about pesticides and what you can do to avoid them.

  • Beyond Pesticides – Fact sheets about specific chemicals and what to do in a pesticide emergency. “Least Toxic” solutions for common household and garden pests.
  • Northwest Coalition for Alternatives to Pesticides – News on pesticide-related issues and healthy solutions to pest problems.
  • Pesticide Action Network Pesticide Database – A database of pesticide toxicity and regulatory information. Reference section provides general information about pesticides and their health effects.
  • Food News – Offers a downloadable wallet card to help you choose produce that lowers your exposure.

General Organic Gardening Strategies Can Help Protect Your Garden From Pests

You may have heard of Integrated Pest Management and wondered what it meant. Integrated Pest Management is a fancy way to describe the practice of planning and working in your lawn or garden to prevent weeds and pests, using chemicals only as the last resort. Here are some basic steps:

1. Learn about the plants and the weeds and bugs that affect them.

2. Choose the right plants. Plant native species whenever possible. Native plants are better protected by their own “immune systems” and their relationships with other plants and animals in the area. You may also look for plants that are pest-resistant. Diversifying the garden with a variety of plants will help the plants protect each other from pests. For example, small flowered plants like daisies, mint, and rosemary attract many insects that eat the pests. Check with a local garden shop or nursery for recommendations.

3. Maintain healthy, fertile soil by rotating your plants, adding compost, and mulching.

4. Plant early to avoid the worst bug season.

5. Allow growth of the pests’ natural predators. Ladybugs, ground beetles, and birds eat many pests, and fungi and moss can infect the pests naturally. Spraying chemicals often kills the beneficial bugs too.

6. Get out there and work with your hands! A hoe, spade, and your hands are the best tools to combat weeds. Getting close to your plants will help you identify problems and remove pests and damaged plants by hand. Tilling can eliminate many weeds as well. Pruning plants helps remove diseased parts, leaving the plant’s nutrients for the healthy parts. Always prune back to a main branch or stem leaving “stubs” opens a door for pests.

7. Keep a garden journal in which you record when you see pests, what they look like, what they have done to the plants, and the actions taken. In this way, you will learn what works and what doesn’t while experimenting with new techniques.

Specific Garden Pests and How to Control Them

Peach Borer

The peach borer is a native of North America, found wherever peaches are grown east of the Rocky Mountains. A closely related species dwells in the West

Vulnerable plants
It is most important insect enemy of peach trees, but also attacks plum, wild and cultivated cherry, prune, nectarine, apricot and various ornamental shrubs.

Peach Borer Appearance and Habits
The first sign of injury is usually a mass of gum and brown frass at the base of the tree trunk, indicating that white worms, with brown heads, are working in the bark, anywhere from 2 to 3 in. below ground to 10 in. above. The winter is passed in this larval stage in spring the borers resume feeding, attain their full inch-long size, then work to the surface of the bark to form cocoons of gum, excrement and bark particles.

Shortly before moth emergence, brown pupa cases are forced partly out of the cocoons. The moths are a little over 1 in. across their wings the males are blue, with transparent, blue-bordered wings the females have an orange band around a blue abdomen, blue fore-wings, transparent hindwings. Each female lays several hundred eggs near the base of the tree trunk, young worms hatching in about ten days to work their way inside the bark. Peaches seldom survive repeated borer attacks.

How to Manage Peach Borers
Dig out the borers when you notice their gummy residue around the base of the tree.

When planting peach trees, make a tin “shield” that circle the tree and fill the space between the shield and tree with tobacco dust. This forms a protective pesticide layer.

You can also encircle trees with moth balls or soft soap.

Coat bark of new trees with Tanglefoot of Stickem.

Plant garlic near the trees.

Squash Borer

The squash vine borer is a native of this hemisphere, occurring east of the Rocky Mountains from Canada to Brazil.

Vulnerable Plants
It attacks squashes and pumpkins and occasionally gourds, melons and cucumbers.

Squash Borer Appearance and Habits
The insect winters as a larva or pupa inside a silk-lined dark cocoon an inch or two below soil level. The adult is a wasplike moth, with copper-green forewings and orange and black abdomen, appearing in June in the Middle Atlantic States. It lays 150-200 eggs, singly, on the stem, especially at the base of the main stem, leaf stalks, blossoms. The young borers hatch in about a week, tunneling into the stem to feed. Usually the first sign of their presence is a sudden wilting of the vine, at which time close examination discloses masses of greenish-yellow excrement protruding from holes in the stem. The borer, a white, wrinkled caterpillar about 1 in. long, can be seen by slitting the stem with a knife.

How to Manage Squash Borers
Baby blue and butternut squash can resist the borer to some degree.

If a change in location is possible, do not grow squashes two years in succession on the same ground. If the same area must be used, spade or plow it in the fall to expose the cocoons. Pull up and burn vines immediately after harvest.

If a vine starts to wilt, kill the borer with a knife and heap earth over the stem joints to start new roots.

Make a second planting of summer squash to mature after the first borer brood has disappeared.

Apple Maggot

The apple maggot or railroad worm is a native, extending from Canada to North Carolina and west to North Dakota and Arkansas.

Vulnerable Plants
The maggot is particularly injurious to summer varieties in northern sections of the country. It also attacks blueberries, plums, and related flies infest peaches, cherries, and walnut trees.

Apple Maggot Appearance and Habits
Hibernation takes place inside a small brown puparium buried 1 to 6 in. deep in the soil. The adult flies do not emerge until summer (late June in some sections, early July in most). They are a little smaller than house flies, black, with white bands on the abdomen and conspicuous zigzag black bands on the wings.

The females lay their eggs singly through punctures in the apple skin in 5 to 10 days these hatch into legless whitish maggots which tunnel through the fruit by rasping and tearing the pulp into brown winding galleries. Early varieties soon become a soft mass of rotten pulp later varieties have corky streaks through the flesh and a distorted pitted surface. Completing their growth about a week after the apples have fallen to the ground, the larvae leave the fruit and burrow in the ground to pupate.

Ordinarily pupation continues until the next summer, but in its southem range, the apple maggot may have a partial second generation.

How to Manage Apple Maggots
Immediately remove and destroy dropped fruit on a large scale this is effective only if implemented over several acres. If the fruit is not too badly infested, it can be turned into cider.

Plant white clover, home to beetles.

Hang fly-traps in trees from mid-June through the harvest, baited with a mixture of molasses, water, and yeast.

Maggots in picked fruit may be killed by holding the apples in cold storage for a month.

Codling Moth

Codling Moth Location
The codling moth, or apple worm, came to this country from Europe about 1750 and quickly became our most destructive pest of apple fruit.

Vulnerable Plants
Codling moths also attack pears, apricots, cherries, peaches, plums, quinces, crabapples and, in California, English walnuts. Unfortunately, spraying with pesticides is often the only effective method of controlling the codling moth, which is why these fruits are the most highly-contaminated with pesticides. (

Codling Moth Appearance and Habits
The insect passes the winter as a full-grown larva, an inch-long pinkish-white caterpillar with a brown head, inside a silken cocoon under loose scales on apple bark or in other sheltered places. In spring the worms change to brown pupae and then grayish-brown moths, 3/4 in. across the wings. These emerge to lay their eggs, singly, on the upper surface of leaves, on twigs and on fruit spurs. They work at dusk, when the weather is dry and the temperature is above 55° F.

A cold, wet spring at the time of egg-laying means less trouble with wormy apples. Hatching in 6 to 20 days, small worms crawl to the young apples, entering by way of the calyx cup at the blossom end. They tunnel to the core, often eating the seeds, then burrow out through the side of the apple, leaving a mass of brown excrement behind, and crawl to the tree trunk to pupate. There are two generations over most of the United States, and in some places a partial third. Second-brood larvae enter the fruit at any point, without preference for the blossom end.

Crop reduction comes not only from wormy fruit but from early drop of immature apples and from “stings” – small holes surrounded by dead tissue which lower fruit value even though the worms are poisoned before doing further damage.

How to Manage Codling Moths
Plant cover crops that support moth-eating beetles.

Hand-remove and destroy larvae.

Band trees with parasitic nematodes.

Clean up the orchard by scraping loose bark from trees and removing rubbish and all dropped apples immediately.

Spotted Cucumber Beetle

Spotted Cucumber Beetle Location
It is found throughout the United States east of the Rocky Mountains, increasing in importance towards the South.

Vulnerable Plants
The spotted cucumber beetle, aka Southern Corn Root-worm or Budworm, belongs to the same genus as the striped beetle but is a much more general feeder. As an adult, it works on at least 200 vegetables, flowers, weeds and grasses, and as a larva, feeds on roots of corn, beans, small grains, wild grasses. An almost identical variety, often called the Diabrotica beetle, is an important flower and vegetable pest in California.

Spotted Cucumber Beetle Appearance and Habits
The greenish-yellow beetles, 1/4 in. long with 12 conspicuous black spots, hibernate in protected places under rubbish or at the base of plants. In spring females lay their eggs just below the ground surface on or near young corn plants yellow-white worm-like larvae with brown heads hatch to burrow into roots and bud. The corn either makes poor growth or dies. As they feed, the larvae also may disseminate bacteria causing corn wilt.

Although spotted cucumber beetles do not cause as much damage to cucurbit foliage as the striped beetles they, too, are carriers of cucumber wilt and mosaic. They are also particularly destructive to flowers, being a common pest of dahlias, cosmos, chrysanthemums and other late bloomers.

How to Manage Spotted Cucumber Beetles
Avoid injury to the corn crop by planting late on land plowed
the previous fall. For cucurbits follow directions given for striped cucumber beetles.

Striped Cucumber Beetle

Striped Cucumber Beetle Location
The striped cucumber beetle is a native of the United States, with a range from Mexico to Canada east of the Rocky Mountains.

Vulnerable Plants
It is a serious pest of the cucurbit family, injuring cucumbers, muskmelon, winter squash, pumpkins, gourds, summer squash and watermelon about in that order.

Striped Cucumber BeetleAppearance and Habits
The winter is passed as an adult – a small, 1/4 in. long yellow beetle with three black stripes, hiding at the base of weeds or under trash, often at some distance from the vegetable patch. The beetles start feeding in early spring on blossoms and leaves of various wild plants, but they migrate to the vine crops as soon as these appear above ground.

Mating soon after migration, the females lay yellow eggs, in crevices in the ground, which hatch into small, worm-like, whitish larvae. These feed on the roots for 2 to 6 weeks, pupate in the soil and, by midsummer, produce beetles which feed on leaves and often fruits until fall. There is one generation in the North, two or more in the South.

Cucumber beetles are injurious not only by the feeding of adults on leaves, stems and fruits, and of larvae on the roots, but also because they are carriers of cucumber wilt bacteria and the mosaic virus. The bacteria, living over the winter in the beetle’s intestinal tract, are inoculated into plants as the beetles feed the virus is acquired while the insects are feeding on weeds in the spring and then transmitted to the vine crops.

How to Manage Striped Cucumber Beetle

Plant late, after the first beetles hatch. Start plants indoors in containers.

Protect seedlings with cheesecloth or nylon tents made by draping cloth over crossed stakes.

Straw mulch keeps adults from walking between plants.

Braconid wasps, nematodes, and soldier beetles consume the cucumber beetle.

Squash Bug

Squash Bug Location
The squash bug is common throughout the United States, ranging from Central America to Canada.

Vulnerable Plants
The squash bug attacks all vine crops, showing a preference for squashes and pumpkins.

Squash Bug Appearance and Habits
The adult bug is dark brown, sometimes mottled with gray or light brown, hard-shelled, about 4″ long. Because it gives off a disagreeable odor when crushed it is commonly called a “stink bug,” but true stink bugs belong to a related family. Unmated adults hibernate in the shelter of dead leaves, vines, boards or buildings and fly to the garden when the vines start to “run.” Mating takes place at that time, and clusters of brownish eggs are laid on the underside of the leaves in the angles between veins. Egg-laying continues until midsummer. The eggs hatch in a week or so into young nymphs with green abdomens and crimson heads and legs, but older nymphs are a somber grayish white with dark legs. There are five nymphal instars, or periods between molts, in the two months before the winged adult form appears.

Squash bug feeding causes leaves to wilt, then turn black and crisp. Small plants may be killed entirely, larger plants have one to several runners affected. Sometimes bugs are so numerous that it is impossible to produce any squashes sometimes they congregate in dense groups on unripe fruits.

How to Manage Squash Bug

Keep squash bugs away from vine plants by also planting marigolds, radishes, or nasturtiums.

Squash bugs like to hide under boards or trash, wherever it is darka and damp. Remove all potential protection.

Handpick beetles and eggs.

June Beetle

June Beetle Location
June beetles, aka June bugs, daw bugs, May beetles, and white grubs, include about 200 species and are distributed throughout North America.

Vulnerable Plants
More than 200 species injure grasses and vegetables in the grub stage and trees as adults. Adult beetles eat leaves of oak, ash, birch, pine and other trees, as well as blackberry leaves. Grubs attack roots of corn, potatoes, soybeans and strawberries.

June Beetle Appearance and Habits
Most beetles have a three-year cycle. Large, dark-brown beetles and white, brown-headed grubs winter in the soil. In spring adults leave the soil at night, flying to feed on leaves, mating, and returning at dawn to lay round white eggs in grassland soil. The grubs hatch in two or three weeks and feed on roots until fall when they work their way below the plow-line for winter.

Working upwards the next spring, they do most of their damage this second season. They grow to about an inch long, being the largest grubs commonly found in soil. The third season they feed until late spring, pupate in soil, change to beetles in late summer, but do not leave the ground until the next spring. Heavy beetle flights are to be expected every third year, but since there are different broods at varying stages in the life cycle, some June beetles appear every spring.

How to Manage June Beetle
Rotate berries with deep-rooted clover and alfalfa.

Tear up infested lawn and grasses, treat with organic fertilizer, and till and plow deeply to destroy the grubs the summer before planting.

Japanese Beetle

Japanese Beetle Location
The Japanese beetle was first noticed in this country in 1916, near Riverton, N. J. Presumably it came from its native Japan as a grub in soil around the foots of nursery stock, or perhaps in a shipment of iris or azaleas. Since its discovery this pest has spread naturally from five to ten miles a year, to cover from Maine to Georgia, and west to Michigan and Missouri.

Vulnerable Plants
Adult beetles feed on foliage, flowers and fruits of almost 300 plants, and grubs work on grass roots. Some of the beetle’s favorite foods include: shade trees such as elm, horse chestnut, linden, sassafras, white birch, willow fruits – grapes, raspberries, peach, apple, plum, cherry, quince flowers – rose, hollyhock, marigold, mallow, spiraea, zinnia vines – especially Virginia creeper vegetables – corn, soybean, asparagus, rhubarb.

Japanese Beetle Appearance and Habits
The beetles are about 1/2″ long, shining bronze-green, with bronze wing covers from under which protrude twelve tufts of white hairs. They are particularly active on warm days, congregating in crowds on the sunniest parts of plants. They are most active on warm, sunny days, and fly only in the daytime. They emerge in late spring and early summer, and are most active for four to six weeks. Seasons following a particularly wet summer usually bring a bigger population of beetles.

During this time, each female lays from 40 to 60 eggs 2 to 6 inches deep in the soil. The young grubs feed on grass roots until cold weather, when they work their way down below the frost line. The grubs are white, hairy, brown-headed 3/4 in. long.

Beetles leave only the veins of leaves, and devour entire flower and fruits. Grubs cut off grass roots so that the sod can be rolled back like a carpet. Beetles feeding on corn silks prevent pollination, resulting in sparse kernel development.

How to Manage Japanese Beetles
The Japanese beetle has many natural enemies: the spring and fall typhia wasps, birds, and skunks are helpful beetle enemies.

Avoid planting turf or sod from outside the area, which may lack the nutrients to support these natural enemies.

Milky spore disease is harmless to plants, animals, and humans, but deadly for the beetle. It is most effective in areas bigger than one acre. Talk to a local garden group or county representative for more information.

Remove diseased fruit from the trees and ground, and keep the area weeded and clean.

Larkspur is poisonous for the beetles, and they avoid the odor of geraniums.

Handpick the beetles and drop them into a bucket of water with a think layer of kerosene.

Traps painted yellow and baited with fermenting fruit, sugar, and water catch thousands of beetles – empty this daily.

Colorado Potato Beetle

Colorado Potato Beetle Location
The Colorado Potato Beetle is a native, and is so common that it is referred to as simply the “Potato Bug.” Found in the Rocky Mountains feeding on Buffalo Bur about 1923, it did not become abundant until the potato was introduced into its territory. Then it spread eastward from potato patch to potato patch, averaging 85 miles a year, until it reached the Atlantic Coast and invaded Europe.

Vulnerable Plants
Although potato is its preferred food, this beetle will eat almost anything available, especially tomato, eggplant, tobacco, pepper, ground cherry, thorn apple, jimson weed, henbane, and thistle.

Colorado Potato Beetle Appearance and Habits
Adults spend the winter buried 8 to 10 inches deep in the soil, emerging in time to feed on the first foliage of early potatoes. They are wide, convex beetles, 1/2″ long, with alternating black and yellow stripes. Females lay up to 20 batches each of orange-yellow eggs in groups on the underside of the leaves, over 4 to 5 weeks. The eggs hatch into humpbacked, purplish-red larvae, with 2 rows of black dots along each side. These larvae eat voraciously, often entirely consuming the leaves. When full-grown they descend into a spherical cell in the ground, transform to a yellowish pupa, and in 5 to 10 days new adults emerge to feed and lay eggs for the second generation.

How to Manage Colorado Potato Beetles
Grow potatoes above ground! Drop potato seeds on 3″ of sod or leaf cover and cover with straw.

Plant natural beetle repellents nearby: flax, horseradish, garlic, eggplant, snap beans, nightshade.

Handpick the beetles and crush the eggs.

Dust the tops of potato leaves with wheat bran. The beetles will eat it and bloat up until they die.

Ladybugs and toads eat beetles.

Spray foliage thoroughly with lead or calcium arsenate, or cryolite, whenever beetles or larvae are present. Either arsenical may be combined with Bordeaux mixture for the control of blight, but cryolite may be used only with a fixed copper free from lime.

Asparagus Beetle

Asparagus Beetle Location/Vulnerable plants
The Asparagus Beetle arrived in this country from Europe about 1856 and is now widely distributed. Larvae and adults gnaw succulent shoots and devour summer foliage, weakening the plants for another year. Asparagus is, apparently, the only host.

Asparagus Beetle Appearance and Habits
The beetles are less than 1″ long, bluish-black, with red thorax, blue and yellow wing covers, the yellow often present as spots. They winter in any protected place, often in trash left around the garden, garages, and homes. As soon as asparagus shoots appear in spring, they begin to feed and lay rows of dark-brown eggs. Gray, black-headed slugs come out in 3 to 7 days, chew on the stems for 10 to 14 days, then pupate in the ground for about a week. The beetles emerge and lay eggs either on stems or foliage. There are at least two generations in the North, more in the South.

The 12-spotted Asparagus Beetle is orange to brick red with, yes, 12 black spots. This species feeds on the shoots, but delays egglaying until shortly before the berries form, when they glue dark green eggs to the leaves. The orange larvae and second generation beetles feed only on the berries.

How to Manage Asparagus Beetles

A clean garden is the best prevention. Eliminate any places the beetle can hide, and till the soil to rouse them from hibernation.

Asparagus beetles do not like tomato plants, and asparagus plants kill the nematodes that often attack tomatoes. Intersperse the plants so that they protect each other.

A cheesecloth netting can protect tender young asparagus.

Birds, chickens, and ducks love to eat the asparagus beetle, and ladybugs and the chalchid wasp feed on the larvae.

Cut the asparagus shoots every 2 or 3 days, before the eggs can hatch.

Dust asparagus with bone meal or rock phosphate.

The spotted asparagus beetle cannot fly in the morning, and can be handpicked.

Elm Leaf Beetle

Elm Leaf Beetle Location/Vulnerable Plants

The Elm Leaf Beetle is believed to have reached Baltimore from Europe about 1834. It is now enormously destructive throughout New England and the Middle Atlantic States, occurs scatteringly westward to the Mississippi, and is found on the Pacific Coast. It is confined to the elm, with Chinese and Siberian elms most severely injured.

Elm Leaf Beetle Appearance and Habits

The adult beetle is 1/4″ long, yellow, changing to olive with age, with black spots on the head and a black band on the outside of each elytrum or wing cover. It winters in protected places, often in houses, and in spring flies to the elm, where it lays a double row of yellow, lemon-shaped eggs on the underside of a leaf. These hatch in about a week into black-spotted larvae, which skeletonize the leaves, eating out everything except veins and epidermis. After 3 weeks of feeding, they crawl down the trunk and pupate at the base, more beetles appearing in 1 to 2 weeks, to eat holes through the leaf. There are two or three generations a year, with the elms either entirely defoliated or covered with crisp brown leaves. Two or three years of defoliation may mean death, and always mean a weakening of the tree so that it is subject to attack by the elm bark beetle, carrier of the spores causing Dutch elm disease.

How to Manage Elm Leaf Beetles

There are no proven methods of preventing the elm leaf beetle’s attack. Protect houses and garages, and keep the beetles from wintering inside, by caulking cracks. Monitor the elms to see if the damage is serious if so, apply a narrow band of pesticide higher than human reach. A relatively harmless homemade pesticide of 3 ozs. laundry soap to 1 gal. of water will kill larvae coming down to pupate.

Gypsy Moth

Gypsy Moth Location

The Gypsy Moth is an expensive pest of shade, forest and fruit trees, especially apple, elm, oaks, and aspen. Accidentally let loose near Boston in 1869, it now inhabits an area from the east coast to Michigan, and as far south as North Carolina.

Gypsy Moth Appearance and Habits

The gypsy moth begins as a brown, hairy caterpillar, 2 inches long, with 5 pairs of blue bumps along the back, followed by 6 pairs of red ones. They feed in June and July, stripping the trees. They pupate inside a few-threads spun on limb or tree trunk and produce moths in 17 to 18 days. The brown, yellow-marked male flies freely, but the heavy female does not use her white wings with their wavy dark markings. Egg clusters are white or yellow and covered with hairs, can be as large as 1/2″ to 1″ in diameter, and are found under tree branches, in gutters, under ledges, or any other good hiding place. Distribution is by crawling of caterpillars, wind dispersal of young larvae, or by the removal of some object, such as an automobile or railroad car, with attached egg case.

How to Control Gypsy Moths

Destroy eggs whenever possible.

In early April, wrap 2″ wide sticky barrier bands around trees. There are many commercially available products, which prevent caterpillars from climbing up the tree.

The Gypsy moth has many natural predators, such as mice, flies, beetles, and wasps.

Spray with BT, twice, 5-7 days apart.

Cabbage Maggot

Cabbage Maggot Location

The Cabbage Root-Maggot, introduced from Europe almost two centuries ago, is now a serious pest in Canada and northern United States, but does not do much damage south of Pennsylvania. It likes cool weather.

Vulnerable Plants

It is injurious to cabbage, cauliflower, broccoli, radishes, turnips and other members of the cabbage and mustard family, and sometimes works on beets, celery and other vegetables. In the fall months of September and October, the larvae attack rutabagas, turnips and brussels sprouts.

Cabbage Maggot Appearance and Habits

The winter is spent as a pupa in an enclosing case (puparium), 1 to 5 ins. deep in the soil. About the time sweet cherries bloom, and young cabbage plants are set out, a small gray fly crawls out of the soil to lay white eggs at the base of the stem and on adjacent soil. These hatch in 3 to 7 days into small, white, legless maggots which enter the soil to feast on the roots, riddling them with brown tunnels. Seedlings wilt, turn yellow, and eventually die. After 3 weeks the maggot forms a puparium from its larval skin and produces another fly in 12 to 18 days. The number of generations is indefinite ordinarily the first feeds on cabbage and its relatives, while late broods menace fall turnips and radishes.

How to Control Cabbage Maggots

Plant after June 1 to avoid major pest season.

Protect seedbeds with a cheesecloth or nylon cover to prevent egg-laying, and secure it to the ground on either side. Place a 3- to 4-in. square of tar paper around stem of each plant set out, at ground level.

It is sometimes possible to remove a seedling at first sign of wilting, wash off the maggots, and replant.

Dust red pepper, ginger, or wood ash around the stem.

  • Cabbage Roof Maggot: A. adult fly B. legless maggot (larva)) E. puparium in soil C. maggots working an roots D. fly laying eggs at base of stem

Cabbage Worm

Cabbage Worm Location

The Imported Cabbage Worm came to this country from Europe, via Quebec, arriving in Massachusetts about 1869, and quickly spread to all parts of the United States.

Vulnerable Plants

It attacks all members of the cabbage or mustard family (this includes cauliflower) and also feeds on nasturtium, sweet alyssum, mignonette and lettuce.

Cabbage Worm Appearance and Habits

The insect winters in the pupa stage, a gray, green or tan angular chrysalid hanging downwards from some object near the cabbage patch. In early spring, the pupa hatches into a white butterfly with three or four black spots on each wing, a wingspan of 1 1/2″ to 2″. They lay yellow, bullet-shaped eggs singly on the undersides of leaves. In about a week, velvet-smooth green caterpillars, with alternating light and dark longitudinal stripes, hatch and start feeding, depositing pellets of dark green excrement as they eat huge, ragged holes in the leaves. They feed for 2 to 3 weeks, then pupate, there being three to six generations in a season.

How to Control Cabbage Worms

Plant tomatoes, onions, garlic, and sage around cabbage to deter the worm.

Cover plants with a lightweight nylon net to keep the butterflies from laying eggs.

Till the soil several times between plantings to destroy eggs and pupa.

Hand-remove larvae. Destroy old stalks as soon as the crop is harvested, and make sure to destroy weeds like Wild Mustard, Pepper Grass, Shepard’s Purse, on which the first-generation worms develop.

A number of natural enemies reduce the caterpillar population, among them common yellow jackets and braconid wasps. Braconid wasps are attracted by strawberries.

The cabbage worm may drown during heavy rains.

Other methods include spooning spoiled milk into the cabbage head, or spraying with a mixture of salt, flour, and water, which will make the caterpillars bloat and die.

Pictures of a Cabbage Worm, above

Cabbage Worm (Life Cycle, page 52): A. adult butterfly B. full-grown worm (larva) C. egg, enlarged 10 times D. chrysalid E. typical damage by worms, adults laying eggs

Corn Earworm

Corn Earworm Location

The Corn Earworm, aka Tomato Fruit Worm, Tobacco Budworm, Cotton Bollworm, is such a successful pest that it lives practically everywhere in the world between the parallels of 50° north and south latitudes. That’s from the bottom half of Canada to almost the tip of South America.

Corn Earworm Appearance and Habits

The earworm winters as a pupa in the soil. A brownish-olive moth coming out in spring to lay 500 to 2500 eggs, one at a time, on various host plants, including weeds. The eggs are dirty white and dome-shaped. After hatching, the caterpillars grow to nearly 2″ long, have yellow heads, and vary from yellow to brown to green with lengthwise alternating light and dark stripes. There are several generations in a season in corn, first-brood larvae eat into developing leaves, while larvae of later broods start at the silk and bore into the tip of the ear, eating the kernels down to the cob and piling up moist castings of excrement. In tomatoes the worms feed on the partially ripened fruit, restlessly moving from one tomato to another pods of lima beans are sometimes invaded.

How to Manage Corn Earworms

Sweet corn is protected by applying mineral oil with a medicine dropper into the silk at the tip of the ear. (1/2 – 3/4 of a dropper). This should be applied after the silk turns brown.

Corn varieties with a tightly closed ear fare better at keeping the corn borer away some farmers have aided the plants by attaching closepins to the ear tips to physically block out the worms.

Other strategies include clipping the silk every four days, and planting marigolds near the corn.

In southern gardens, the tomato fruit worm may be controlled by applying pinches of bait to the fruit clusters.

European Corn Borer

European Corn Borer Location

The European Corn Borer, discovered in Massachusetts in 1917, has spread throughout most states east of the Rockies.

Vulnerable plants

The corn borer eats more than just corn. It will bore into a wide variety of plants with large stems, stalks, and fruits, such as bell peppers, snap and lima beans, potato vines, tomatoes. It also attacks flowers: dahlias, gladiolus, and large-stemmed ornamental and weed plants.

European Corn Borer Appearance and Habits

The corn borer winters in larva form, an inch-long, flesh-colored caterpillar with inconspicuous black dots, in old stalks left around the garden and pupates in the same stalk. Yellow-brown moths appear in late May or June to lay white eggs on the underside of corn leaves over a period of 3 or 4 weeks. These eggs start hatching about a week later, and the young larvae chew small, round holes in leaves and move toward and into the plant stalk, leaving behind sawdust-like excrement on the leaves and outside the stalk. If you see bent stalks, the larvae have already done a lot of damage inside the plant.

How to Manage European Corn Borers

Uprooting, shredding, and burying infected stalks is the most successful method of destroying the corn borer because it kills the wintering larvae. Although this method does not salvage the affected plants, it will protect the next year’s harvest.

Late plantings are more vulnerable to the corn borer. Corn or other affected plants should be planted early, to grow while other plants are also bearing fruit.

Removing the borer by hand is the oldest remedy. Split the stem a little below the entrance hole and pick out the worm.

Other methods include attracting the corn borer moth to light traps, or using parasitic insects such as the ladybug, which will consume up to 60 borer eggs a day.

Spray natural pesticide BTK ( on undersides of leaves and into tips of ears after silks wilt.

Pictures of a European Corn Borer

  • European Corn Borer (Life Cycle, page 51): A. adult moth B. larva, a smooth caterpillar C. pupa and larva inside corn stem, borer frass protruding from hole D. female moth laying eggs on corn leaf E. borer working in ear of corn, with frass protruding F. borers overwintering in old corn stalks

Vegetables: The Brassicas—Troubleshooting Common Pests of Broccoli and Cauliflower

Are there holes in your broccoli and cauliflower leaves? Have you lost young plants or had older ones die after wilting? There are a number of culprits that attack vegetables in the Brassicaceae family, but if you can ID those critters, you can still have a good fall crop—better yet, you can learn how to prevent future infestations!

Cabbage white moth on kale

Brassica line-up
Although we’re focusing on broccoli (Brassica oleracea var. italica) and cauliflower (Brassica oleracea var. botrytis), note that you may find similar problems on your Brussels sprouts, cabbages, and other “crucifers” (so-named for their cross-shaped flowers), including arugula, bok choy, collards, kales, kohlrabi, mustards, radishes, rutabagas, and turnips!

All the pesky pests
Although holes in the leaves are often the most obvious indication of insect damage, pests also damage Brassica stems and roots. Here are the villains:

  • Aphids—Cabbage aphids, despite their name, can also do serious damage to broccoli and cauliflower by sucking on the foliage, depositing honeydew, which attracts ants, and transmitting viral diseases.
  • Cabbage maggot—These fly larvae attack Brassica roots and underground stems, stunting plants or causing them to wilt. This damage is most significant in young plants, but in older plants, leaves may yellow and plants may die if roots rot from bacterial or fungal pathogens. Brassica root crops—radishes and turnipsmay have significant damage from tunneling maggots.
  • Cutworms—These fat larvae of nightflying moths can encircle stems of young plants and cut them off at the soil level. Both black and granulate species prey on Brassicas.
  • Flea beetles—These tiny beetles are responsible for minute holes in leaves and cause serious damage to new starts with few leaves.
  • Other “worms”—Probably the most annoying Brassica pests are a plethora of other moth and butterfly larvae: cabbage loopers, cabbage worms, cabbage webworms, corn earworms, and diamondback moth larvae feed on both leaves and stems. These range in size.

What to do?
Prevention is best!

  • Aphids—Aphid eggs can overwinter in the soil and on plant debris, so cultivating the area you are planting and disposing of infected plants will help deter future infestations. The good news is that many beneficial insects—think lady beetles—devour or parasitize aphids so know your “good bugs”! Researchers find planting nectar sources nearby, such as sweet alyssum, can help attract beneficials. Reflective mulches, such as aluminum foil, may also help deter aphids.
  • Cabbage maggot—Rotate crops and cover young plants with row covers to prevent egg-laying.
  • Cutworms—Keep planting areas free of weeds, as well as plant debris, to reduce cutworm populations. Larger transplants and rapidly growing seedlings are less susceptible, but use “collars” made of aluminum foil, cardboard, or tin cans half-buried in the soil around young plants to prevent stem damage.
  • Flea beetles—As for aphids, cultivation, cleanup, and attracting beneficials can help reduce flea beetle populations. Proper watering and fertilization keep young plants growing well and can get them through their greatest vulnerability. Trap crops, such as Chinese Southern Giant Mustard (Brassica juncea crispifolia) and radishes—particularly Chinese Daikon and Snow Belle—will take flea beetle pressure off other Brassicas, according to researchers. If you are certain beetles aren’t already present in the soil or on the plants, row covers will protect them, too.
  • Other “worms”—Row covers or small-mesh netting (no larger than 7mm-square holes) will keep most of the eggs of leaf-eating “worms”— laid by assorted butterflies and moths—off your plants so the larvae never hatch out.

Treatment for serious infestations:

  • Aphids—Spraying with plain water may dislodge enough aphids to save your plants. If not, insecticidal soap sprays should work.
  • Cabbage maggot—Beneficial nematodes may help, but these require careful handling and attention to soil temperatures and moisture levels to be effective.
  • Cutworms—No pesticide treatments are recommended for home gardens.
  • Flea beetles—Insecticidal soaps may be somewhat effective. Check with Extension for other pesticide recommendations.
  • Other “worms”—Bacillus thuringiensis (Bt) is an effective control, but is an indiscriminate killer of caterpillars. So, don’t spray on host plants of desirable butterflies.

Don’t forget that one of the most effective ways to protect from pests is to fence out the mammal marauders, such as groundhogs and rabbits, that may be the most serious predators of your vegetable garden!

Article written by Debbie Green, Extension Master Gardener SM Volunteer.

For more information
Integrated Pest Management (IPM)
by NC State Extension

Ready to Grow

With a reputation for being a finicky plant that’s challenging to grow, it’s important to remember that with the right growing conditions, you can avoid most of the problems described above.

Disease-resistant and certified disease-free cultivars, cool temperatures, even moisture, good airflow, and nutrient-rich soil go a long way toward ensuring good plant health.

And with an understanding of 12 common diseases, you can use proactive measures to avoid trouble, and recognize issues in time to take action.

Have you experienced any of these diseases on your crops? Let us know in the comments below!

And for more information about growing cauliflower in your garden, check out these guides next:

© Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Uncredited photos: Shutterstock.

About Nan Schiller

Nan Schiller is a writer with deep roots in the soil of southeastern Pennsylvania. Her background includes landscape and floral design, a BS in business from Villanova University, and a Certificate of Merit in floral design from Longwood Gardens. An advocate of organic gardening with native plants, she’s always got dirt under her nails and freckles on her nose. With wit and hopefully some wisdom, she shares what she’s learned and is always ready to dig into a new project!

Watch the video: How to control Grey aphids on your Cabbage, Broccoli, Cauliflower and Brussels Sprouts.

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