GardenLine | Porpourri - Miscellaneous | More Beneficial Bugs

Wood was an instructor with the Department of Horticulture Science. This column is offered as an Extension Service by the Division of Extension and Community Relations and the Department of Horticulture Science, University of Saskatchewan.

Many of these insects are small and not readily noticed, but they are very effective in controlling harmful insects.

BRACONIDS-These time (2.5 mm) wasps are mainly parasitic in behavior. The females lay eggs in their prey. The developing larvae inside the host insect eventually kills the host. Common host insects include aphids and larvae of many insects such as moths, butterflies, beetles, flies, mosquitos, midges, scale, plant bugs, and leafhoppers. Braconids can be identified by the dark spots of their wings.

ICHNEUMON WASP-These wasps are very closely related to the braconids. Often referred to as ichneumon flies, they are larger (15-25 mm) than braconids and equally effective in controlling other insects. All ichneumon wasps are parasitic like the braconids, and they feed on many of the same hosts-especially larvae of the spruce budworm and leaf roller.

FIREFLIES-These insects are actually beetles not flies. The male fireflies are winged; often the females are wingless, or fly very little. Males are the conspicuous sex, with their illuminating body organs. Females and the larvae form can be luminous, and are referred to as glow-worms. Both adults and larvae are insect predators, feeding on snails, slugs and many other insect larvae. Most fireflies hibernate over winter in the soil; this gives them a 2-year life cycle. Fireflies are nocturnal for the most part, and are usually only seen at night. Adult beetles are only about 15 mm. long.

TACHINA FLIES-Another of the parasitic insects, these flies belong to a very large family that is of great economic significance in biological pest control. The adult fly is about 15 mm. in length and is usually dark colored with lighter markings much resembling the common housefly. Host insects include larvae of many moths, butterflies, beetles, and especially sawfly larvae. Adult flies are often seen in flowers feeding on the nectar. They also consume honeydew secreted by various other insects, and then often parasitize the insect that produced the honeydew.

FLOWER FLIES-Also called syrphids, these flies look more like wasps or bees, with their black body and yellow bands. Flower flies are also called "hover flies" because the male flies are often seen hovering over a flower. They dart quickly when disturbed. Most flower flies feed on aphids, grasping their prey and sucking out the body fluids. Some flower flies are parasitic, laying eggs on the eggs of harmful insects. Larvae of the flower fly are slug-like and are found in plant leaves, in soil and in water. Both larvae and adults have insatiable appetites for aphids. Adult flies are about 15 mm. in length.

WASPS-You may not think of wasps as being beneficial insects, especially if you have ever been stung by one. In fact wasps are predators on many insects and their young. Mud daubers are solitary wasps that build nests of mud, then lay eggs inside. These wasps feed their developing young a diet of insects and spiders. Social wasps such as hornets and yellow jackets also feed their young a diet of insects, especially in the larvae or worm form. Cabbage worms and army worms are a favorite meal for wasps. Not common are the parasitic wasps who lay their eggs in host insects. Most wasps feed on nectar and pollen from flowers and therefore are also beneficial in assisting pollination.

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Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.