Beneficial Insects

Not all Insects are pests!!

Actually most are beneficial because they pollinate
our crops, recycle dead things or prey on pest insects. It is in our
own best interest to let these creatures do their job and even attract
and help them exist in our environment. The statement "A Good Bug is
a Dead Bug" is definitely wrong. True, some insects are pests. But we
could try to let the good ones control the bad. An old English saying:
"If it moves slow, step on it:. If it moves fast, leave it be - it will
probably kill something worse". So it is better to look a little closer
at nature before you act. Beneficial Insects can be classified as Predators
or Parasites. Predators feed on other insects, while Parasites use other
insects for their home or as food for their offspring.

Ladybugs These beetles usually have 12 spots, but could have 2, 7, 9, 13 or 15. Normally orange to red, they could also be yellowish brown. They feed on Aphids, Scale and other small insects. Their larvae are also predatory, even more voracious than adults. Ladybug eggs are orange and may be found standing on end in groups of 20 or more. View examples of other life stages at right side of page.
Aphid Midges (Gall Midge larvae) Tiny, black nocturnal flies with long legs feed on "honeydew" secreted by Aphids and lay eggs near Aphid colonies. The legless, orange to red larvae drink body fluids leaving black, dry and dead Aphid bodies.
Lacewings These green or brown Insects with large lacy wings feed on nectar, pollen and "honeydew". Females deposit white eggs on foliage. Each egg of the green Lacewing is suspended at the end of a long slender white silk stalk on the underside of leaves. The larvae, also known as Aphid-Lions are ferocious insect killers and prey on Aphids, Leafhoppers, Mealybugs, Scale Insects, Spidermites and other sucking insects.
Ground Beetles Mostly black or dark blue shiny Beetles feed at night on cutworms, root maggots and other soil insects. Some feed on Slugs and Snails. Some ground Beetles can irritate the skin, so wear gloves when you find one in the house and put it outside. Their larvae feed on caterpillars and are slender and segmented, slightly tapering to the tail and ending in two hair-like appendages.
Rove Beetles Recognizable because the abdomen lifts upwards when in motion or disturbed. These insects are mostly found in decaying organic matter and feed on Slugs, Snails, Rootmaggots etc.
Syrphid Flies Adult flies, also known as Hover Flies feed on nectar and pollinate flowers. These flies are often confused with Wasps, but these insects have only one pair of wings. Their eggs are shiny white and elongated and are placed one at a time among groups of Aphids. The larvae are small, green or light brown, slug-like maggots with pointed jaws. These prey on Aphid after Aphid (sometimes one every minute) by grabbing them and lifting them in the air and draining them of fluids.
Tachinid Flies Adult flies resemble Houseflies and feed on nectar. The flies are hairy and gray or brown in colour with pale markings. Females glue eggs on another insect's body (like on Armyworms) or on leaves that are then ingested by the host. The eggs hatch and the maggots will eat their way through the host, eventually killing it. Caterpillars, Beetles, Grasshoppers, true Bugs etc. are all victims.
Parasitic/ Predatory Wasps Braconid, Ichneumon and Chalcid Wasps are parasitic. They lay their eggs in or on host insects, such as Caterpillars, Cutworms, Aphids, Whiteflies, Leafhoppers etc. Wasp larvae will live inside the host, eventually killing it. They pupate inside the body or on the surface. Predatory Wasps kill or paralyze the prey and feed it to its young.
True Bugs Mostly pests but some are beneficial, such as Predator Stinkbugs and Spined Soldier Bugs. However these bugs can also prey on Ladybugs and other beneficial insects, even their own nymphs. They pierce and suck the juices from their victims.

Attracting Beneficial Insects

Attracting and maintaining a population of beneficial insects are important to managing insect pests in your garden with a minimum of pesticide sprays. Tiny parasitoid wasps are aggressive beyond their size when it comes to pursuing aphids and caterpillars. Lacewing larvae and ladybug larvae and adults make inroads on aphid populations. Ground beetles prey on a variety of ground-dwelling pests.

These various beneficial insects consume large numbers of pest insects, but their diets are not limited to other insects. In fact, many of the beneficial species have periods in their life cycles when they survive only on nectar and pollen. Therefore, planting a variety of insectary plants will ensure an adequate supply of nutrients to keep beneficial insects going strong. Insectary plants also include those plants that provide shelter for beneficial insects, another critical requirement.

At one time, hedge rows that separated one field or garden from the next provided an ample supply of insectary plants to feed and shelter a variety of beneficial insects. The wide variety of plants in a hedge row, including small trees and shrubs as well as perennial and annual weeds, typically leaf out and bloom earlier than most crop plants, providing beneficial insects with an early food supply.

Most gardens today are too small for a hedge row. An alternative is to plant a border of dwarf fruit and flowering trees mixed with flowering shrubs and perennials. Such a border could be a landscape feature and screen the vegetable garden from view. At the same time, it would provide many of the benefits of the traditional hedge row.

Plan an insectary border for successive bloom from early spring through fall, providing nectar throughout the season. This will not only satisfy the needs of many beneficial insects, but also provide color in the garden. Avoid vigorous chemical control of pests found in the insectary border; after all, you don't want to kill beneficial insects. Also, any pests in the border may become hosts for beneficial insects should prey levels be low in the garden you are trying to protect.

Including plants of different heights can be very important. Ground beetles require the cover provided by low-growing plants. Lacewings lay their eggs in shady, protected areas, so providing such places near crop plants is a good idea.

Selective weeding can encourage beneficial insects by leaving potential food sources in the garden. Allowing certain volunteers to remain in the garden is somewhat like random companion planting. Just know what weeds or volunteers are helpful. Not all blooms are equal -- large, nectar-filled blooms actually can drown tiny parasitoid wasps. Tiny flowers produced in large quantity are much more valuable than a single, large bloom.

Many members of the Apiaceae (formerly known as Umbelliferae) family are excellent insectary plants. Fennel, angelica, coriander, dill, and wild carrot all provide in great number the tiny flowers required by parasitoid wasps. Various clovers, yarrow, and rue also attract parasitoid and predatory insects. Low-growing plants, such as thyme, rosemary, or mint, provide shelter for ground beetles and other beneficial insects. Composite flowers (daisy and chamomile) and mints (spearmint, peppermint, or catnip) will attract predatory wasps, hover flies, and robber flies. The wasps will catch caterpillars and grubs to feed their young, while the predatory and parasitoid flies attack many kinds of insects, including leafhoppers and caterpillars.