Garden pests are extremely annoying, particularly when tons move in, chomping leaves and nibbling your fruit and vegetables. But you shouldn’t wait for them to do visible damage before you take action. If you spend just a little bit of time learning about the different pests you might find in your garden, and the types of plants they are more likely to attack, then you will find you are able to manage most pest problems with minimal effort.
Here are some of the most common pests you are likely to find in your vegetable garden (in alphabetical order), as well as plants that they like most, and what you can do to get rid of them.
Asparagus beetles are quite common, but it appears that asparagus is the only vegetable they attack. If they manage to find asparagus, the larvae – gray, black-headed slugs – and the blue-black and red beetles, with their blue and yellow wing covers, will gobble up shoots and foliage. The beetles lay their eggs on stems and foliage.
There is also a 12-spotted asparagus beetle that is an orangey color with 12 black spots.
Asparagus beetles will multiply in garbage and dirty gardens. They don’t like tomato plants, so this is the perfect companion plant. Birds, chickens and ducks love these beetles, but they may do as much damage to the plants!
Cabbage maggots attack cabbages, cauliflower, broccoli, radishes, turnips and sometimes other vegetables like beets and celery. Their larvae will attack turnips, Brussels sprouts and rutabagas.
These maggots emerge from the soil in early spring in the form of small, gray flies that lay white eggs at the base of stems and on the soil. It takes less than a week for the eggs to hatch horrid little legless maggots that go straight back into the soil to gobble up the roots of their favorite veg. Newly-planted seedlings quickly turn yellow and die. It takes little more than a month for the maggot to reappear as a fly!
Dusting with red pepper, ginger or wood ash sometimes helps to keep maggots away. If seedlings start to wilt, check for maggots. It is sometimes possible to wash the maggots off and flush them out of the soil – and replant the seedlings. You can also protect the beds where seeds have been planted with cheesecloth or nylon sheeting.
Cabbage worms attack lettuce, cabbages and other mustard family vegetables including cauliflower.
You may spot a gray-green or brownish chrysalids hanging downwards on various objects near to cabbage patches. Then early in spring, pretty white butterflies with three or four spots on each wing, emerge to lay little yellow eggs on the underside of leaves including weeds like wild mustard and pepper grass. And it takes only about a week for smooth, green caterpillars with light and dark green stripes to emerge. For the next two to three weeks they will do their damage, gobbling up leaves before pupating. The huge, ragged holes that they make in leaves are unmistakable.
Since there will be as many as three to six generations of cabbage worm in any one season, it is good practice to cover susceptible plants with nylon netting to keep the butterflies away. Companion planting with tomatoes, onions, garlic and sage is also helpful. Braconid wasps, which are attracted by strawberries, will also help to reduce the number of caterpillars. Otherwise you can remove caterpillars by hand and destroy them, or spoon over-boiled milk into the head of the cabbage or even spray with water to which a little flour and salt has been added.
Corn borer doesn’t just eat corn. It burrows into many other vegetables and fruits, including bell peppers, beans and tomatoes, and will also attack large-stemmed flowers like dahlias and gladiolus.
You will find the larva of corn borer in old stalks, in the form of an inch-long black spotted caterpillar. Then in early summer yellow-brown moths emerge and lay their white eggs on the underside of the plant leaves. When they hatch, the larvae go to work again, chomping leaves and then making their way into their stalky homes.
You can remove caterpillars by hand and kill them, but you will also need to destroy any infected stalks which may be harboring eggs or newly hatched larvae. You can also use a natural non-toxic pesticide like BTK (Bacillus thuringiensis kurstaki)
Corn earworms, which are also known as tomato fruit worms, are incredibly common in most parts of the world.
Brownish-olive colored moths emerge out of the ground and lay hundreds and thousands of dirty, off-white eggs on the leaves of various plants including corn, tomatoes and lima beans. These hatch caterpillars with yellow heads and yellow, green and brown stripes that grow as long as two inches.
You can keep them out of sweet corn by applying drops of mineral oil to the silky ends at the tip of the corn ears when the silk starts to turn brown. Growing marigolds as a companion plant also seems to help. Special bait may be used to keep these worms away from tomato plants.
Japanese beetles feed on hundreds of different plants, including their leaves, flowers and fruit. The grubs of these beetles also work their way into grass roots. Favorite vegetables include corn, soybeans, asparagus and rhubarb.
You can identify Japanese beetles by their color (shiny bronze-green) and by the fact that they have little tufts of white hair that protrude from under their wings. They are most active on warm, sunny days, and often work en masse.
Female beetles lay eggs from two to six inches into the soil – and the grubs do great damage to grass roots.
If you can remove beetles, drop them into a bucket of water that has a thick layer of kerosene on top of it. You can also make traps baited with fermenting fruit, sugar and water. Some people find they can catch thousands of beetles with these.
June beetles or rather June bugs (because the grubs of what damage vegetables) attack the roots of corn, potatoes, soybeans and strawberries. They also attack the leaves of blackberries.
The grubs are white with brown heads, while the beetles are large and dark-brown in color. These beetles have a much longer life cycle than many other garden pests – about three years. The adults live in the soil, but emerge at night during the spring months to fee on leaves and to mate. Then they return to the soil to lay more eggs. When the grubs hatch they feed on roots, doing most damage in their second year.
If lawns are infested with these pests, tear it up and start again. If there are just a few visible beetles pick them off.
Potato bugs (or more strictly Colorado potato beetles) adore potatoes, but will also eat tomatoes, eggplants (brinjals), peppers and some fruits.
Black and yellow striped adult beetles spend the winter months deep in the soil. When they emerge, they lay batches of orange-yellow eggs on the underside of leaves. These hatch purple worms with two rows of black dots along each side that will consume every leaf they can get their little mouths around.
Natural beetle repellents include flax, horseradish, garlic and snap beans. If you can pick beetles off, do so, but be sure to crush the eggs. You can also dust potato leaves with wheat bran which the beetles will eat, causing them to bloat and die. Otherwise try spraying with basil water. There are also various chemical pesticides available for potato bugs.
Squash bugs love squashes and pumpkins and they will also attack all vine crops. Plants will wilt and usually turn black and die.
The adult bug is a dark brown color, sometimes a little mottled. It is bigger than most other bugs (usually about four inches long) and when crushed absolutely stinks! However it is not a true ‘stink bug’. Before they mate, these bugs live in dead leaves or in boards or even buildings. Once they mate they lay clusters of brown eggs on the underside of leaves in between the veins. Eggs hatch into nymphs with green bodies and bright crimson legs and heads that eventually turn to gray before become a winged adult bug.
Good companion plants that help to keep squash bugs away are marigolds, radishes and nasturtiums.
Spider mites are tiny (a fraction of an inch) and they can do a lot of damage. There are various types, and you will find them on the under sides of plant leaves.
The best way to control spider mites is with specially developed pesticides. However there are some beetles and thrips that will destroy them naturally. But be aware that thrips are also a pest.
Spotted Cucumber Beetles
Spotted cucumber beetles are general feeders that attack more than 200 vegetables, flowers, weeds and grasses, feeding on roots and grains.
These beetles are a greenish-yellow color and they have 12 obvious spots on them. The adult females lay eggs underground, but quite near to the surface, usually near to young corn plants. When the little wormy yellow-white larvae hatch, they burrow into roots and buds.
These beetles are managed the same way as striped cucumber beetles, which are even more of a pest.
Squash borer is a vine borer that attacks squashes, pumpkins and sometimes also gourds, melons and cucumbers.
The adult of this pest is a moth that is quite like a wasp, with copper-green front wings and an orange and black body. It lays up to 200 eggs on one stem and when the young borers hatch, they immediately bore into the stem to feed. If vines start to wilt, slit the stem. If squash borer is the culprit you will find a white, wrinkled caterpillar inside the stem.
The best management procedure is to remove and destroy any vines that are attacked by squash borer.
Striped Cucumber Beetles
Striped cucumber beetles attack cucumbers, muskmelons, winter squash, pumpkins, gourds, summer squash and watermelon.
This pest is a little (1/4 inch long) beetle with three black stripes feed on blossoms in spring, as well as on the leaves of some wild plants. They also feed on vine leaves. Females lay yellow eggs in cracks in the ground and these eggs hatch into little white larvae that eat roots. The beetles also carry various bacteria and a virus that affects cucumbers.
The best way to manage these pests is to plant cucumbers late, after the beetles have thatched. You can also protect seedlings with cheesecloth or nylon material and use straw mulch between the plants.
Thrips are tiny insects with fringed wings – also called thunderflies, thunderbugs, storm flies and corn lice. They feed on crops and are a huge pest.
Thrips are difficult to control without pesticides.
Tomato hornworms are green caterpillars with eight V-shaped markings on its side that can be a terrible pest in the garden. There are several different sorts with different horns.
They are commonly found on tomato plants and tobacco leaves, but also attack eggplants, peppers and potatoes.
The best way to get rid of these caterpillars is to plant marigolds around tomato plants.