Black swallowtail caterpillar
Small black leaf beetle
Brown stink bug
Grasshopper
As I transitioned my style of gardening towards companion planting, I witnessed an explosion in the population of insect life in my garden. Damsel flies whirred by my shoulders, ladybugs greeted me perched on the edges of plant leaves, beetles scurried away every time I moved a bit of soil, and the bees, well, the bees were everywhere! I really began to take note of how many insects were in my garden, and how many kinds of insects I had invited to stay. I also sought to identify the garden insects I had attracted and comprehend exactly how they contributed to my garden’s success. The following categories examine the role these insects might play in your garden, where you might see them, and any specific identifying characteristics.
Predatory insects are tiny hunters; they are a regiment of insects at your side to help you combat pests. Armed with pincers, piercers, and poisons, they are very capable, and as hunting is a natural instinct, they need little encouragement.
The manner in which predatory insects take down their victims rivals the storyline of any horror movie. Some predatory insects crush their prey with mandibles. Others pierce them with their jaws or beaks, paralyze them with venom and suck out the “body juice.” Tiger beetles will lie in wait in tiny holes, and wait patiently, even days or weeks, for prey to stroll by. When an unsuspecting insect comes too close, they snap forward at blinding speed, and attack.
Soldier beetle
Praying Mantis carve out their own territory for their hunting escapades. It’s likely that you’ll only see one in your garden, and it may even turn its head to give you a once over. While praying mantis are often friendly to humans, they will take down Japanese beetles, and many other pests, by grasping them with their powerful legs, and then eating the beetles alive. Ladybugs or beetles will breed more rapidly when they’ve noticed a high density of aphids.
The aggressive hunting instinct of predatory insects explains why they’re bestowed with names like pirate, soldier, or assassin. The following three charts describe most of the more common garden predators.
Ladybugs on tomatillos
Pollinators make it possible for your fruiting vegetables to reach optional productivity. Most of the foods you cultivate in your garden require pollination. Pollinators seek out garden flowers to eat nectar. They also are there to attract mates and will utilize the “floral oils” generated by flowering plants. These insects pollinate accidentally. As they visit flowers, pollen rubs on their bodies—they will then carry that pollen from plant to plant.
To attract pollinators to your garden, pick perennial flowers that showcase large clusters of blooms and an extended blooming time. Pollinators are the easiest to spot in the garden because many are most active during the daytime and during warm weather. (Most moths are nocturnal.)
We noticed an increase in pollination once we started keeping honeybees. Here, Tim’s inspecting the hive.
Eastern carpenter bee visiting some hairy mountain mint
A honeybee on anise hyssop
Black swallowtail caterpillar
Skipper
Black swallowtail butterfly
Black swallowtail caterpillar on parsley
Parasitoid insects spend a portion of their lives growing on or inside the body of a host. These insects will attach to the host when they lay eggs on host eggs, larva, or they might even insert their eggs into full-grown insects. Once the parasitoid eggs hatch, the larva will then feed on the hosts as they grow. Aphidiid wasps will eat the interior of their aphid hosts, and then emerge once they’ve reached adulthood. The easiest way to spot the work of the aphidiid wasp is to look for a pile of dead aphids. Some species of beneficial beetles also exhibit parasitoid characteristics.
These insects most commonly attack pests, and they rarely go after beneficial insects. Most have a specific pest that suits their fancy.
In my plant-by-plant guide, I describe the most common pests that attack specific plant species. However, there are some garden pests that are more indiscriminate when choosing their victims. Many organic gardeners reduce pest populations by hand picking pests, squashing eggs, or implementing floating row covers.
If one were to read a sampling of gardening literature these days, it would appear that gardeners spend most of their time in the garden battling insect pests. Whole garden books are devoted to techniques that have been devised to eradicate pest infestations. Honestly, most of these insects have made such little impact on my garden that I wouldn’t have even noticed them unless I decided to look. Companion planting keeps nature in balance. I decided to include specific descriptions here because I think it’s important to have an awareness of the biodiversity in your garden. Please don’t see the following words as instructions to seek and destroy.
Aphids—Aphididae
Aphids are minutely sized insects measuring only 1/6 of an inch to 3/8 of an inch in length. While most are colored green or black, others can be pink, brown, gray, or blue. When aphids attack plants, they will suck the juice. The leaves will lose their vigor, curl and yellow, and eventually drop. As the plant weakens from the attack, it will lessen its fruit and flower production. The secretion excreted from the aphids is called honeydew. The honeydew is often eaten by ants, and it can cause black mold to grow on infected plants that will prevent photosynthesis.
Thankfully, aphids are a favorite among predatory insects, especially ladybugs. They can also be knocked from an infested plant with a quick blast from a forceful water hose. Aphids don’t like odorous herbs like chives, mint, catnip, or alliums.
Likely Victims:
Aphids aren’t picky eaters. They suck the sap from a wide range of vegetables and fruit plants, flowers, bushes, and trees.
Cutworms—Noctuidae
Cutworms are dastardly demons that can dash a new gardener’s hopes and dreams in a single night. The worms are actually the larvae of a night flying moth. They inflict their damage by chewing through the stems of young seedlings or transplants.
Predatory insects will eat cutworms, but I’ve found that the best way to ensure protection for my young transplants is to surround them with a small barrier. I’ve used newspaper and toilet paper rolls, but my favorite barrier involved reusing old cat food tin cans with the bottoms removed. Newspaper must be cut and rolled around each plant, and it slows down planting day. I keep my tin cans from year to year, and plunk them down around each seedling once they are in the ground. Make sure to lightly push each can into the soil so that an inch remains above the ground.
Likely Victims:
Cutworms will attack any plant with a singular stem—like peppers, tomatoes, or broccoli.
Japanese beetle
Earwigs can be classified as beneficial insects and as pests. They’re a predator to aphids and nematodes, but they will also eat tiny holes in leaves, and sometimes, in fruit. They measure 1/2 of an inch to an inch in length, and they are brownish red with pinchers at the end of a curling tail.
Before setting a trap for the earwig, weigh the damage they’ve inflicted against their overall benefit in the garden. Most earwigs will only impose a trifling amount of disruption. Trap earwigs by placing a tubelike structure in proximity to their feeding area. A rolled up newspaper, piece of bamboo, or a cardboard tube will work fine. The insects feed at night, so pick up the tubes and empty them in the morning.
Likely Victims:
Earwigs munch on lettuce, strawberries, corn silk, and numerous flowers.
Leafhoppers—Cicadelliade
Leafhoppers are 1/4 of an inch in length and appear in a wide range of colors, including brown, yellow and green. They “hop” from plant to plant and attack plants by sucking plant juice from leaves. You can spot their damage by looking for white spots on the leaves. Plants with extensive damage will have wilted, yellowed leaves and stunted growth. They can survive the winter in piles of garden debris.
Ladybugs, lacewings, and pirate bugs all attack the eggs and larvae of leafhoppers.
Likely Victims:
Leafhoppers favor beans, beets, lettuce, and potatoes.
Japanese Beetles—Papillia japonica
Japanese beetles are probably the most visible garden pests. They measure 1/2 an inch in length as adults, and they have metallic green backs with bronze wings. The beetles eat foliage of all kinds and sometimes small fruit like raspberries. They are often found in mass numbers munching and mating on a tree, shrub, or garden edible. Most Japanese beetles live in the eastern portion of the United States.
If a plant is shaken, the beetles will protectively drop to the ground. To slow their progress, take a bucket of soapy water, and gradually knock the beetles into the bucket. Try to repeat this process every few days until the beetle population appears to have been reduced.
Likely Victims:
Japanese beetles will attack a wide range of leaves, flowers, and fruits.
Root Knot Nematodes/Eelworms—Nematoda
Nematodes most often live in the soil. They are often microscopically sized, however some can reach up to 1/4 of an inch. Some help gardeners by feeding on pests or breaking down decomposing organic material in the compost pile. Others attack plant matter by injecting saliva, and then sucking out softened tissue. You won’t really see the nematodes in action; instead, you will witness the results of their feasts. Crops damaged by nematodes will most likely turn yellow, and their growth will be anemic. The roots will be riddled with lesions or nodules, or showcase an excessive amount of root growth. Some also carry damaging viruses.
Nematodes are not the average garden pest. If you’ve seen signs of their damage, you might have to let the infected beds lay fallow for a year to starve them from the bed. Some studies have noted that nematode populations can be significantly reduced by planting marigolds as a cover crop, and then turning them under at the end of the growing season. To avoid this predicament, remember to always rotate your crops from year to year.
Likely Victims:
Parasitic nematodes will attack most plants, likely any plant with a root.
Slugs—Mollusca
Slugs slink around wet shady sections of the garden—under low growing vegetation or wooden boards. Although you might not spot the slugs, you will see the slime trails they leave as they slither, and giant holes in your leaves from their binge eating. Slugs are from the mollusk family and can range in size and length. Most measure around 1 inch long, although some reach 7 or 8 inches.
Gardeners have developed ingenious methods to deal with slug infestations. Slugs will be distracted away from your edibles by a shallow tin can full of beer. If you find your beer too valuable to feed to the slugs, try placing wooden boards around infected areas. The slugs will congregate under the boards at night, and can be picked off in the early morning. Slugs are also deterred with a copper border (it will shock the slugs), or with a sprinkling of lime, crushed seashells or coffee grounds.
Slugs also possess many natural predators. Toads eat slugs, so add a toad home to your strawberry beds. Predatory insects like ground beetles and fireflies will also eat slugs. Slugs favor red clover more than most anything else, so try planting the cover crop as a trap crop.
Likely Victims:
Slugs eat beans, strawberries, and all kinds of salad greens.
Thrips/Thunder flies—Thysanoptera
Thrips are slender insects that generally measure less than 1/2 of an inch in length and have fringed wings. Some thrips will attack other pests, but others will attack plants and they can also carry disease.
Likely Victims:
Thrips aren’t picky about their prey. They are noted for eating onions, beans, carrots, and squash.
Root Maggots—Delia
Root maggots are 1/5 of an inch in length, pale yellow, and almost transparent in color. They bore into root vegetables, and the roots of vegetables, and create a network of tunnels that will cause the plant to yellow and even die.
Most infestations are avoided by rotating crops from year to year. Gardeners also sprinkle dried hot peppers around root crops to discourage the maggots.
Likely Victims:
Root maggots are found in onions, cabbage, radishes, carrots, and turnips, and they are more likely in northern gardens.
Milkweed borer
Egg mass of the three-lined potato beetle
Wheel bug, a member of the assassin bug family
Nurseries and online catalogs often tout boxes of beneficials that you can purchase, and then release into your garden. I’ve never found this to be necessary. Spend the money on flowers, and the insects will follow. Otherwise, without the necessary habitat, the insects will leave, or they will die off within a generation.
