Beneficial Insects for New England Gardening
Most Insects Are Very Beneficial to Gardens

Beneficial insects have controlled insect pests since the begining of time. It is estimated that 97% of insects in the home landscape are beneficial insects or harmless innocent bystanders. The army of beneficial insects in your garden should be encouraged and protected. Some are predators, they eat pest insects. Others are parasitic, they lay eggs and live in the bodies of pest insects weakening and killing the pests. Many supplement their diet with pollen and nectar while they search for prey pest insects.

Insect identification is important: know which are the friends and which are enemy. Just because an insect is on a plant doesn't mean that it is doing damage. Unfortunately, recent cultural practices have negaiively impacted the populations of beneficial insect populations. It is often illegal and ineffective to apply a pesticide to a pest or plant that does not appear on the pesticide label. Plants that are not on the pesticide label may also be harmed by pesticides. Proper identification may allow you to avoid the use of a broad-spectrum pesticide that kills not only the pest you’re trying to control, but many beneficials as well. Make use of the University Cooperative Extention Service personel and fact sheets available online.

Here in New England how can I attract beneficial insects to my garden to feed on some of the insect pests?
One easy thing to do is keep several shallow dishes of water and pebbles in your gardens for the beneficials to drink from. Grow a few plants that attract the beneficial insects to the garden. Adults of certain parasitic wasps and predators feed on pollen and nectar. Clovers, Queen Anne's lace and plants in the Umbelliferae family, such as dill, fennel, anise, and sea holly are good nectar sources.

Also consider plants in the daisy family, such as yarrow, aster, mum, coneflower, blanketflower, black-eyed Susan, goldenrod, coreopsis and gayfeather. Veronicas and butterflyweed are also attractive to beneficial insects.

Avoid using all pesticides unless there are no beneficial insects present. Use pesticides only when really needed and only on the specific insect causing the damage. Most insect damage is only unsightly and the plant is not actually at risk.

Why do lady beetles vary in color and number of spots on their wings? Lady bugs range in color from yellow to almost red, and vary in the number of spots that occur on the wing covers. If the beetles are dark orange or reddish, then they have been eating mostly aphids, if they are more pale orange or yellow, they have fed more on pollen. The number of spots relates to air temperature during their development.

I’ve seen an odd bug devouring aphids in my garden. It looks like an insect size orange alligator. Do you know what it could be?
Yes, that is a lady bug, also called lady beetles. They have a ferocious appetite for aphids and will clean up the aphids in your garden for you. Considered one of the most beneficial and easily recognized insects. However, when it is in the larva stage it is often confused with insects that would harm plants. It does not harm plants at any stage of it's life.

Ladybugs have invaded my house again. What can I do about them without harming them?
Cut a nylon stocking foot off, and insert foot portion into the tube hose end of your vacuum cleaner. Stretch the cut portion over the tube end and fasten with rubber bands. Vacuum and gently release the ladys back outdoors.

Are there other beneficial insects besides ladybugs that I can attract to my garden?  Yes, below is just a very short list of beneficial insects, desription, and examples of just some of the pest insects they help eliminate.

Tachinid Fly: Diptera: Tachinidae They look similar to house flies, adults are hairy, gray or brown, ³/₈ - 1 inch long. Tachinid flies are very important enemies of cutworms, tent caterpillars, gypsy moths, sawflies, Japanese beetles, squash bugs, sowbugs corn borers, corn earworms, cabbage loopers, imported cabbage worms, and armyworms. These tiny parasites are highly effective against many species of caterpillars and moths that eat leaves and cause root damage.  Tachinids can have several generations per year. Most widely purchased beneficial bug in the world. Grow pollen and nectar plants to attract them.

Organ Pipe Wasps Trypoxylon politum

Also known as Mud Daubers, and Blue Devils
They are quite large, and they are not intimidated by your presence, so, if they fly around you, they might be a bit frightening but they rarely, if ever sting anyone. They just "look you over," then go about their business of pollinating, finding pest insects, building and provisioning their nests. These wasps are known for the architecture of their nests, which are tubular nests of mud, and resemble organ pipes. Actually they prefer high quality clay, and have been known to lead people to clay deposits for use by potters. They are all black and glistening blue in the sunshine. It’s a nervous sort, characterized by flicking wings every few seconds, even when it is otherwise still. Her primary reason for being is to reproduce. To do that she has to build a nest and fills it with paralyzed insect prey. She gathers mud from wherever it can be found and builds her nest in a sheltered spot, under the eaves, or inside an abandoned building. Some fear this harmless and beneficial wasp, and knock down these nests whenever they see them around their home. They lose a thing of beauty when they do. Wonderful pollinators and predators this beneficial insect should be welcomed in your garden.

Braconid parasite Apanteles sp. The photo shows the pupal cocoons of this parasite on the hornworm. Hornworms (Sphingidae) are parasitized by these insects. The adult wasp inserts its eggs beneath the skin of the hornworm larva. The eggs hatch and the young braconids feed on the hornworm. This parasite is an important factor in control of hornworms and is most beneficial. Should you find a hornworm in your garden with the protruding cocoons you should move the hornworm a good distance from your plants (usually tomato plants) but avoid harming it so that the Braconid parasite can develop, and multiply.

Spiders: Arachnida Araneae All spiders feed on insects and are very important in preventing pest outbreaks. The spiders normally found in New England gardens do not move indoors, nor are they poisonous. Permanent perennial plantings and straw mulches will provide shelter and dramatically increase spider populations in gardens.

Ground beetles: Large, long-legged, shiny blue-black or brown beetles hide under rocks and logs during the day, and are fast-moving when disturbed. They feed on slugs, snails, cutworms, root maggots, and Colorado potato beetle larvae. Attract them by providing perennial ground covers, stones, or logs. Rove beetles resemble earwigs without pincers, and feed on many insect pests and like similar conditions to ground beetles.

Fireflies:  Coleoptera Lampyridae are long, soft-bodied beetles, up to ³/₄ inch long. Most larger members have light-producing organs on the end of the abdomen. Most smaller species do not. The females of some species are wingless and look like larvae. The larvae are flattened, have toothed edges, and may also glow. The firefly larvae are a ravenous predator that feeds on snails, slugs, cutworms, mites and pollen. They inject strong paralytic and digestive juices into their prey and then suck the dissolved body contents, leaving a shell. Larvae live one to two years in the soil, and in late spring build a marble-sized mud house around themselves and change to a pupa. In about 10 days, new adult beetles emerge. They emerge in early summer and remain active throughout August. The adults mostly do not feed, but may take an occasional meal of pollen or nectar.

Parasitic nematodes: are microscopic worms, which seek out and then eat their way into the bodies and killing many soil dwelling pests including grubs, weevils and webworms. Nematodes have a fascinating life cycle that makes them part predator, part parasite, part pathogen, and part scavenger. Juvenile nematodes swim through damp soil to find a host and enter through an opening. Once inside, the nematode releases bacteria from its gut, which kill the host within 24-48 hours. They then feed on the dead insect tissues, grow to adulthood, mate, and lay eggs. The new juveniles, carrying the bacteria, leave the host and go in search of another victim.  There are several different types, all attack certain kinds of insects. More information will be available on another future page. Soil conditions and the method of releasing the nematodes are critical, so be sure to read and follow the directions.

Trichogramma Wasps: Hymenoptera Trichogrammatidae  are tiny wasps ¹/₁₆ inch long which prey on the eggs of more than 200 worm type pests, including borers, webworms, and many types of moth caterpillars. The wasps lay their eggs directly into the pest's eggs, killing the eggs as they hatch. The larger the host, the more eggs laid. As soon as the wasps mature, they will fly off in search of new eggs to parasitize. Different species of Trichogramma wasps are more effective against certain pests. 

Hover Flies: Diptera Syrphidae Also known as flower flies or syrphid flies. Adults look like very small bees with striped abdomens; the grayish or greenish slug- like larvae have pointed heads. Flower flies are attracted to flowers to feed on nectar and pollen. The larvae feed on aphids in tight places where other good bugs can't go, and are especially helpful in early spring, before other beneficial insects are active. Hover flies also pollinate strawberries and raspberries, producing larger fruits and higher yields.

Ichneumon Wasp - Hymenoptera Ichneumonidae This family of Wasps is one of the largest of all insect families and has more than 60,000 different species including many that are so tiny you can barely see them. Ichneumon wasps are extremely variable but are mostly slender with long antennae. Some species have a very long egg-laying device (ovipositor) extending from the end of the abdomen.
Ichneumons are parasitoids, the larva feeds and develops on or in a single host that it eventually kills. Some attack a wide variety of pests others are highly specific to one or a small group of host species.

Bumble Bee and Honey Bees are extremely important pollinators and can be used effectively for the pollination of a variety of crops, like tomatoes, sweet peppers, eggplants, melons, strawberries, apples, pears and cherries. Improved pollination results in larger more abundant fruits and vegetables.

Cryptolaemus Beetles resembles the Ladybug but is darker in color. They will seek out and consume mealy bugs. The eggs are usually laid on an infested plant so that the larvae can feed on the mealy bugs as soon as they hatch.

Ladybugs (Ladybird beetles) feed on aphids, chinch bugs, whiteflies, and mites, as well as many other soft-bodied insects and their eggs. There are more than a hundred ladybug or "lady beetle" species. Each adult may consume as many as 5,000 aphids during their adult life. When mature, each female will begin to lay as many as 3-4 dozen eggs each day. Upon hatching, each ladybug larvae will begin consuming 50 aphids each of the 21 days until they reach the adult stage, when the cycle begins again. That's a lot of aphids and undesirables removed from your plants.

Spined Soldier Bug with its pointed shoulders, prey on many types of beetles, webworms, armyworms and other garden pests.

Decollate Snails - Attack and kill the common brown garden snail.  Also eat snail eggs and juvenile snails.

Predatory Mites - Prevent stunting and yellowing of plants by attacking red spider mites, two spotted mites, and other common mites found in greenhouses and gardens.

Leafminer Parasite: This tiny insect kills leafminer larva in the mine and lays an egg in it. The egg develops into a parasitic wasp inside the mine but outside the leafminer, using the dead larva as food.

So many other insects not listed are also very beneficial. Shown here pollinating the Delphinium 'Blue Butterfly' is the Hummingbird Moth. It is often mistaken for the Hummingbird. We have very frequent sightings of Hummingbirds and hummingbird moths at the garden center.

For an excellent source of garden bug photos, or submit a photo for identification visit What’s that Bug?

Don't forget there are other types of "beneficials" besides insects: Frogs, toads, birds, bats, and others devour large quantities of insects. Garden snakes, fox, coyote and birds of prey keep populations of moles and voles under control.

 Links: USA University Cooperative Extension Service

Insect Identification site:  What's That Bug?