With the help of the list of beneficial insects and their images presented in this Gardenerdy article, you can convert your garden into a habitat for these helpful arthropods, and can minimize pest problems.
Did You Know?
Over 97 percent of the commonly seen insects are either beneficial or harmless. Few arthropods are actually pests.
Arthropods are said to be beneficial when they eat other arthropods that are considered as pests. By planting specific trees, you can attract beneficial insects to your garden, or you can buy these insects from catalogs. Preying on harmful insects or their larvae, they help control many garden pests. Taking into consideration the nature and type of pest infestation in your garden, you can buy particular species of beneficial insects. Usually, for every pest, there exists a natural control. These days, beneficial insects are used in commercial pest management programs.
Three Types of Beneficial Insects
The insects which help control pests do not harm pets, plants, and human beings. These useful arthropods are divided into three types: predators, pollinators, and parasitoids. Predators live by preying on pests. They kill and feed on prey. Naturally, they are larger and stronger than their prey. Parasitoids are insects that lay eggs on or within their hosts. They are smaller than the hosts. When the eggs hatch, the newly-emerged larvae feed on their host insects, causing their death. Some adult parasitoids act like predators. They don’t lay eggs on the hosts, but feed on their blood. This doesn’t help kill the host, but it definitely weakens it. The main difference between these two classes is that predators attack, kill, and eat ‘many’ pests, and can control the infestation relatively fast. Parasitoids can kill only one insect (host) or a ‘few’ pests each. However, both types are good for organic pest control. Pollinators include several bee and fly species. As the name suggests, they bring about pollination and help produce more fruits. Here is a list of some common beneficial insects that play an important role in pest control.
Most Common Beneficial Arthropods
1. Lady Beetles (Hippodamia convergens)
Size: From 0.06 inch to 0.38 inch.
Color: They come in vibrant colors; for example, orange, black, pink, or yellow, with or without spots.
Description: The lady beetle is one of the most popular beneficial insects. These dome-shaped insects are commonly known as ladybugs or ladybird beetles. There exist hundreds of species of this bug. For example, Hippodamia convergens, Harmonia axyridis, andEpilachna varivestis.
Use: Both adults and larvae feed on aphids, insect eggs, mealybugs, and other soft-bodied insects, and mites. They are especially useful for controlling aphids (one ladybug can consume hundreds of aphids in its lifetime), mealybugs, and spider mites. Both adults and larvae are predators.
How to Attract Them: Flowering plants that produce nectar in abundance can attract them. For example, dill, fennel, yarrow, angelica, caraway, golden rod, etc.
2. Ground Beetles (Family Carabidae)
Size: 0.25 inch to over 1 inch long.
Description: There exist more than 40,000 species of ground beetles worldwide. They have long legs, prominent eyes, and thread-like long antennae. These nocturnal insects have strong jaws.Calosoma sycophanta is a climber. As the name suggests, ground beetles live in soil and detritus.
Use: They can kill small snails, slugs, ants, maggots, earthworms, caterpillars (including armyworms, cutworms, and grubs), and other insects. Both adults and larvae are predators.
How to Attract Them: Ground beetles get attracted towards cover, water, and light at night. Stones, logs, bricks, or plants that act as ground cover (amaranthus, clover, or vetch) can provide ample space to hide during the day. They are equally attracted towards mulch. You may keep a shallow pan filled with gravel and water, for them. You may install solar path lights in your garden.
3. Hover Flies (Family Syrphidae)
Size: 0.50 to 0.75 inch long.
Color: They can be identified with the help of the yellow/orange and black banded abdomens. Slug-like larvae are grayish or greenish.
Description: These flies look like wasps. They are also known as flower flies or syrphid flies. They have only two wings.
Use: Adults mostly feed on nectar and pollen, but their larvae eat aphids hidden in narrow, compact places where other helpful bugs can’t enter. Surprisingly, these are active in early spring, way before other beneficial insects are active.
How to Attract Them: As the name suggests, flower flies are attracted to flowers.
4. Green Lacewings (Chrysoperla rufilabris)
Color: Pale green, tan, or brown. Green lacewings have large copper-colored eyes.
Description: They have large, distinctive, veined wings.
Use: Adults feed mainly on flower nectar, pollen, and even honeydew. The alligator-like larvae feed on aphids, thrips, scales, moth eggs, small caterpillars, and mites. Green lacewing larvae, aptly known as ‘aphid lions’, can devour large numbers of aphids, mites, lace bugs, and other small insects with their hooked jaws.
How to Attract Them: Green lacewings are attracted to lights at night. So solar lights can be installed on pathways.
5. Praying Mantis (Tenodera aridifolia sinensis)
Size: 1 to 4 inches long.
Color: Brown or green. They can change their color according to the surrounding environment.
Description: They have a long, stick-like body, and a triangular head. When they fold and hold their front legs, they resemble a praying position.
Use: These large insects feed on pests like aphids, flies, leafhoppers, crickets, spiders, small frogs, flies, and beetles. If sufficient pest bugs are not available, they might eat other mantis or some beneficial insects.
How to Attract Them: Good hiding places and plenty of insects (food) can attract them. Plants belonging to rose, raspberry, shrubbery, etc., can provide shelter to these insects.
6. Tachinid Flies (Family Tachinidae)
Color: Gray, black, brown, some are brightly colored.
Description: There exist about 1,300 species in North America alone, and the appearance may vary from species to species. They are often mistaken for house flies, wasps, or bees.
Use: Tachinid fly larvae dig their way into the body of the host, for example, gypsy moth caterpillar. They consume caterpillars, destroying them from the inside. They help get rid of cutworms, armyworms, tent caterpillars, cabbage loopers, gypsy moths, sawflies, Japanese beetles, squash bugs, grasshoppers, and sowbugs. As adults feed on flowers and nectar, they are important pollinators too.
How to Attract Them: Plant pollen and nectar producing plants like dill, parsley, sweet clover, and other herbs to attract adult flies.
7. Pirate / Flower Bugs (Orius insidiosus)
Size: Tiny, teardrop-shaped, about 1/20 inch long.
Color: Black and white patterned, brown, or yellow-orange.
Description: It is a very small, quick-moving insect. It pierces pest insects with its beak-like structure and sucks out the body fluids.
Use: This insect, during all its stages, consumes pests that are in their developing stages. It is useful in field crops (corn, soybean, tomatoes, etc.), especially if you want to get rid of thrips. It eats a variety of small pests. It would kill pests even when its stomach is full. Its diet consists of aphids, spider mites, thrips, caterpillars, and their eggs.
How to Attract Them: Plant goldenrods, daisies, alfalfa, vetch, sweet clover, and yarrow to attract them.
8. European Hornet (Vespa crabro)
Size: about 2 – 3.5 cm in length.
Color: Brown and yellow.
Description: Females sting when stepped or grabbed. Males cannot sting. Hornets have brown and yellow striped, hairy abdomens and C-shaped eyes. The thorax is also hairy.
Use: They eat various types of pests. They kill them with stings and jaws. However, they may destroy domestic honeybee hives.
How to Attract Them: They feed on nectar and sugar-rich plant foods. So, plants that produce flowers and fruits would help attract them. Sap producing trees like oak can also attract them.
9. Parasitic Nematodes (Steinernema feltiae)
Size: In fact, these are not insects. They are tiny, usually microscopic non-segmented worms.
Color: Usually, soil-like.
Description: There exist more than 25,000 species of nematodes. They belong to the phylum Nematoda. They have tubular digestive systems, with openings at both ends. About one million individuals can be present in one square meter ground area.
Use: These roundworms can help control caterpillars or grubs, especially during spring or fall (depending upon the type of pest). They attack larvae of soil-dwelling pests. They enter into the body of the prey through body openings or directly through skin, and release bacteria that kill the host within 2 days. They can then reproduce inside the pest. They can kill various kinds of harmful larvae (over 230 different pests), for example, termites, fleas, web-worms, sod web-worms, fungus gnats, flea larvae, spidermites, weevils, white grubs, rootworms, cutworms, etc. They do not kill lady bugs, earthworms, or most other beneficial insects. They are useful for all types of gardens, for example, lawns, vegetable gardens, and gardens with lots of shrubs and trees.
How to Attract Them: These naturally occurring species have adapted to all types of ecosystems. Excessive use of chemicals can destroy them. In that case, you may have to purchase them. They grow well in moist conditions.
10. Mites and Spiders
Size: Usually small, but there exist large-sized species.
Color: Gray, brown, black, etc.
Description: Although mites and spiders are not insects (they are arachnids, they have eight legs, not 6 like insects), they are often labeled as insects because they are arthropods. Predatory mites are extremely small. They dwell in trees, shrubs, and surface litter.
Use: Phytoseiid mites help get rid of various plant-feeding mites, such as spider mites, rust mites, cyclamen mites, thrips, and other small pests. Most soil-dwelling mites eat nematodes, insect eggs, fungus gnat larvae, or decaying organic matter. Spiders are also some of the best pest predators. They eat flea-hoppers, aphids, sorghum midge, armyworm, leafhoppers, leafminers, spider mites, spruce budworm, pine sawfly, and tobacco budworm. They prefer eating caterpillars, thrips, plant bugs, cucumber beetles, grasshoppers, scarabs and flies. Unfortunately, they may eat some beneficial insects like bees.
How to Attract Them: Avoid using toxic sprays or dust in the garden.
11. Parasitic Wasps
Size: Wasps belong to different families, mainly Chalcids, Braconids, and Ichneumonids. They may vary in size and colors. Most are tiny, less than one eighth of an inch long. Trichogramma wasps are pencil-point sized, while black ichneumonid wasps are very large in size. Chalcids are very small, 1/50 to 1/16 inch long. Adult Ichneumonid and Braconid wasps are usually 0.5 to 1.5 inches long.
Color: Chalcids are dark-colored, often metallic blue or green.
Description: Ichneumonid and Braconid wasps are slender and long-legged. Their abdomen is usually longer than the head and thorax combined. A female has a long needle-like structure at the end of the abdomen to insert eggs into the body of the host.
Use: A parasitic wasp injects its eggs inside an aphid (host). When the larvae come out of the hatched eggs, they eat the aphid from the inside out. Some lay a number of eggs in a caterpillar or other types of hosts. Thus, they bring about the death of the host. They can attack aphids, various types of caterpillars, cicadas, lace bugs, scale insects, white-flies, sawfly larvae, ants, leafminers, and insect pupae. They also attack the eggs of insects such as codling moths, tomato hornworms, cabbage loopers, imported cabbageworms, and European corn borers. Ichneumonid and Braconid wasps kill caterpillars.
How to Attract Them: Plant nectar-producing plants, especially plants with small flowers, such as dill, parsley, wild carrot, and yarrow to attract them.
Research shows that fruit and flower-bearing plants help attract beneficial insects. They promote longer survival of beneficial insects and encourage production of more progeny. Thus, they help control the growth of undesirable insects. However, the results may not be seen immediately. And once you opt for natural pest control methods, you are supposed to use minimal pesticides. See to it that the pesticides are ‘friendly’ to the beneficial insects in your garden.