Beneficial Insects: Nature's Pest Control
Give your garden an extra hand by attracting these beneficial insects to your yard.When gardeners think about insects in their garden, it’s usually about pests that cause damage to ornamental and edible plants. In fact, most insects are not harmful, and some are even beneficial, supporting plant health through pollination and pest control.
Having a diverse insect population in your garden that includes these helpful insects is an integral part of having a balanced ecosystem. Attracting beneficial garden insects to your yard is one of the safest and most effective methods of natural pest control. Though insect pests may not be completely eradicated, damage to plants can be reduced and better managed with biological control methods. Learn how to recognize beneficial insects and how to attract and keep them in your yard.
On this page: Types of Beneficial Insects | 12 Common Beneficial Insects | How to Support Beneficial Insects
On this page:
TYPES OF BENEFICIAL INSECTS
There are three main types of beneficial insects:
- Pollinating insects move from plant to plant, transmitting flower pollen to perform the essential function of fertilization. Without these insects, plant diversity and crop yields would be adversely impacted. Pollinators include butterflies, moths, bees, wasps, flies, ants, and beetles.
- Predatory insects feed on other insects, either in adult or larvae form. They are useful for controlling a wide range of insect pests. Predators include lady bugs, lacewings, ground beetles, spiders, flies, and praying mantis.
- Parasitoid insects lay their eggs on or inside a host insect, where the hatched larvae feed on the host, killing it in the process. Most parasitoids are tiny stingless wasps or flies.
Many predators and parasites are also pollinators, primarily in the adult stage.
12 COMMON BENEFICIAL INSECTS
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ASSASSIN BUG
Assassin bugs can grow to 2/5 to 4/5 inch long, with elongated features. Many are black or brown, while some are brightly colored. Some 200 species are native to North America. This long-lived predatory insect consumes a large number of pests during its lifetime, feeding on a variety of insects including aphids, beetles, caterpillars, flies, and leafhoppers by piercing the victim with its curved dagger-like beak and sucking out bodily fluids. Avoid touching assassin bugs, as they can deliver a painful stinging bite.
How to attract assassin bugs: Include daisies, goldenrod, marigolds, Queen Anne’s lace, and herbs such as dill and fennel in your garden.
How to keep assassin bugs in your yard: Provide places for assassin bugs to hide such as wood piles, mulch, or leaf debris where they can ambush their prey.
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BEES
Bees are among the most important pollinators. Without them, plant reproduction and crop yields would be greatly diminished. This large group of beneficial insects includes honeybees, bumble bees, mason bees and native bees.
How to attract bees: Provide a wide range of flowering plants including natives that bees rely on as a nectar food source. Some of the best plants for bees include asters, chives, coneflowers, and sunflowers.
How to keep bees in your yard: Provide bee houses for mason bees and other hole-nesting bees for shelter and nesting places. Leave bare soil areas for bumblebees, which will nest in underground tunnels beneath the soil. Place shallow water dishes around the yard with small rocks or pebbles that bees can stand on while they drink.
Learn more about creating a bee-friendly garden.
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DAMSEL BUG
Damsel bugs, which are native to North America, grow up to ½-inch long and are distinguished by slender features and brown, black, or beige coloring. This beneficial predator is most active during summer months. Adults and larvae eat a wide variety of soft-shelled insects including aphids, cabbage worms, small caterpillars, spider mites, and thrips.
How to attract damsel bugs: To entice damsel bugs to your garden, plant caraway, fennel, and spearmint. They are also attracted to crops such as alfalfa, clover, and soybeans.
How to keep damsel bugs in your yard: Adult damsel bugs overwinter in protected sites with ground cover plants or leaf debris. Leave garden beds undisturbed until spring.
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GARDEN SPIDER
These 8-legged predators,which are considered arachnids rather than insects, build webs to trap pests such as aphids, beetles, caterpillars, fruit flies, and grasshoppers. After spinning its web, a garden spider lays in wait for its prey to get tangled in the web, then injects venom to immobilize it. The prey may be eaten immediately or saved for a future meal.
How to attract spiders: Provide places around your yard where spiders have enough room to spin their webs.
How to keep spiders in your yard: Provide protection from the elements in the form of mulch, grass clippings or dead leaves. Empty flower pots turned on their side, or protected areas around your home’s exterior are also places where spiders can shelter.
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GREEN LACEWING
One of the most valuable garden insects, green lacewings provide pollinating and predatory benefits. Adult lacewings reach 1/2 to 3/4 inch long, and are named for their green or yellow-green coloring and lacy transparent wings.
Adults are pollinators that feed on nectar, pollen, and honeydew secretions, and can occasionally be predacious. Lacewing larvae feed on soft-bodied pests including aphids, caterpillars, leafhoppers, mealybugs, spider mites, thrips, and whiteflies, consuming as many as 200 pests in a week. Lacewings are often used for pest control in greenhouse environments.
How to attract green lacewings: Plant angelica, caraway, cosmos, dill, and yarrow to attract lacewings.
How to keep green lacewings in your yard: Tolerate a certain amount of aphids and other pests in your yard so that lacewings have a consistent food source. Adults and pupae overwinter in debris piles and fallen leaves. Leave garden cleanup until spring to avoid disturbing overwintering insects.
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GROUND BEETLE
Ground beetles, which comprise 2,500 different species, are recognized by their shiny black or brown wing covers and long legs. Beneficial in both the larvae and adult stages, ground beetles feed on a wide range of garden pests such as cabbage maggots, caterpillars, cutworms, silverfish, slugs, snails, and thrips.
These nocturnal predatory insects begin their life cycle by laying eggs around the base of perennial plants during late summer, where the eggs will overwinter until spring. Ground beetles also eat plant material found in compost piles, aiding with the decomposition process.
How to attract ground beetles: To encourage ground beetles into your yard, plant a perennial border and keep an active compost pile going.
How to keep ground beetles in your yard: Delay cleaning up your garden until spring so overwintering ground beetles are not disturbed.
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HOVERFLY
Also known as syrphid fly, this beneficial insect is named for its ability to hover in mid-air and fly backwards, an unusual trait for insects. These pollinating and predatory insects are ½-inch long at maturity, resembling bees or wasps with black, yellow, or white bands.
Adults feed on pollen and nectar, while larvae prey on pests such as aphids, beetles, caterpillars, scale, and thrips. A single larva can consume up to 400 aphids during its lifespan.
How to attract hoverflies: Grow alyssum, chives, cosmos, dill, zinnias, and other flat-shaped flowers that have easily accessible nectar for hoverfly adults.
How to keep hoverflies in your yard: Provide early spring blooming plants for emerging insects to feed on and delay garden cleanup until spring to avoid disturbing adults and larvae that overwinter.
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LADYBUG
Also known as lady beetles, these charming predatory insects reach 1/8-inch long, and are recognized for their orange-red shell with black spots. Lady beetle larvae eat a large volume of pests including aphids, leafhoppers, mealybugs, scale, spider mites, and whiteflies. They are often used in greenhouse environments to control common pests.
How to attract ladybugs: In addition to eating pests, ladybugs also rely on plant pollen as a source of food. Plant angelica, calendula, cilantro, cosmos, marigold, and yarrow to attract ladybugs. Nurseries will often sell bags of adult ladybugs to home gardeners as a natural pest control.
How to keep ladybugs in your yard: Place shallow saucers around the yard that are filled with water and pebbles for ladybugs to perch on. Provide shelter and hiding places such as leaf piles, ground cover plants and dense shrubs. If you decide to purchase ladybugs to release in your garden, you can keep them around longer by releasing them just before dusk, spraying down nearby plants with water, and releasing them near a food source such as an aphid infestation or favorite flowers.
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PARASITIC WASP
This diverse group of small to medium sized parasitoid insects lay their eggs on a range of host insects including beetles, caterpillars, sawflies, and tomato hornworms. They are commonly used in greenhouse environments to control common pests such as aphids, mealy bugs, spider mites, and whiteflies. Adults consume nectar and pollen and are non-stinging insects. Not all parasitic wasps are beneficial, so proper identification is essential to attracting and keeping these insects in your yard.
How to attract parasitic wasps: Adult parasitic wasps prefer plants in the carrot family such as caraway, cilantro, dill, fennel, and Queen Anne’s lace. Include these plants in your yard to attract these beneficial insects.
How to keep parasitic wasps in your yard: Provide a consistent source of water and food.
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PRAYING MANTIS
This larger beneficial insect is easy to identify for its long body features and alien-like appearance, though its green coloring can make it hard to spot. Praying mantises appear in the garden from mid-summer to fall, eating a wide range of pests including beetles, caterpillars, crickets, and moths. This ruthless predator also feeds on beneficials such as bees, butterflies, and even hummingbirds.
How to attract praying mantises: Grow shrubs, dill, and marigolds, or keep a patch of tall grass to attract praying mantis.
How to keep praying mantises in your yard: Plant dense shrubbery or keep a patch of tall grass where praying mantis can shelter and lay their eggs. Females lay their eggs in fall, which hatch in spring. The eggs are protected by a sac-like covering which is usually attached to a branch. Avoid disturbing overwintering egg cases and delay garden cleanup until spring.
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SOLDIER BEETLE
Soldier beetle, which is related to firefly, has an elongated ½-inch long body with soft wing covers, occurring in colors of black, yellow, or orange. The larvae prey on pests including aphids, caterpillars, cucumber beetle, grasshopper eggs, and a variety of soft-shelled insects. They will also eat beneficial or harmless insects. Adults are pollinators, feeding primarily on nectar and pollen.
How to attract soldier beetles: Plant catnip, goldenrod, hydrangea, Queen Anne’s lace, marigold, yarrow, and zinnias to attract soldier beetles.
How to keep soldier beetles in your yard: Females lay their eggs in garden soil, and larvae overwinter in leaf piles, plant debris and loose soil. Leave garden cleanup until spring to avoid disturbing overwintering insects.
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TACHINID FLY
Tachinid flies, which look similar to houseflies, grow ¼ to ½-inch long, with a brown or black body and red, orange, yellow, or tan markings. Adults are pollinators, feeding on nectar and pollen.
The larvae of these parasitoid insects help control a wide range of pests including armyworms, beetles, cabbage loopers, corn borers, grasshoppers, gypsy moth caterpillars, Japanese beetles, sawflies, and squash bugs.
How to attract Tachinid flies: To attract tachinid flies to your yard, grow plants with flat-topped flowers such as buckwheat, cilantro, coriander, dill, and parsley, as well as clover and anise hyssop.
How to keep Tachinid flies in your yard: Some species overwinter in leaf litter, while larvae may spend the winter inside the pupal cases of their victim. Delay garden cleanup until spring.
6 WAYS TO SUPPORT BENEFICIAL INSECTS
Beneficial insects, like all living animals, need food, water, and shelter to survive. Make your yard more inviting by providing these basic needs.
1. Grow a diversity of plants. Plant a mix of trees, shrubs, perennials, and annuals in your yard in a layered tapestry to provide food, shelter, and places for insects to lay their eggs and overwinter. Include plant varieties that are native to your particular area. Early bloomers such as alyssum and crocus and late flowers such as asters and goldenrod provide a consistent food source throughout the growing season. Flowering herbs such as dill, fennel, and mint, along with compound flowers such as Queen Anne’s lace and yarrow, are preferred food sources for many beneficial insects.
2. Keep plants healthy. Provide the right growing conditions, water, light, and fertilizer to keep plants growing their best, which will make them more resilient to pest outbreaks.
3. Include water sources. Set out shallow saucers around the yard with water and pebbles to give insects a place to rest while they drink.
4. Provide protection. Nonflying beneficial insects such as ground beetles and spiders need a place to hide from their enemies. Include ground cover plants and coarse mulches such as bark or straw in your yard where these insects can escape.
5. Delay fall garden cleanup. Many beneficial insects, their larvae and eggs overwinter in plant stems, fallen leaf debris and garden soil. Wait until spring to clean up your garden to avoid disturbing overwintering insects.
6. Eliminate the use of chemical insecticides and pesticides. Chemical pest controls can kill good bugs as well as pests, so are not recommended for use in the home garden.
