Some insects can be used to control other insects. They either prey on them or parasitize them, destroying them in the process. Insect predators work very well in a greenhouse, but in the garden you may have trouble convincing them to stick around long enough to attack your pests. You may need to make a special effort to provide them with a good home, including plenty of food, and attractive plants.
The following may be available on special order from your garden center. Or they can be ordered from Better Yield Insects, 13310 Riverside Dr. E., Tecumseh, Ontario, N8N 1B2.
| Trichogramma wasps |
These tiny parasitic wasps attack over 200 species of insect pests, including fruit-worm, cutworm, tent caterpillar, codling moth, and spruce bud-worm. Eggs are laid in the insect, and develop there, destroying their host when they emerge as adults. Can be bought as eggs.
| Praying mantis |
Young praying mantis eat aphids and leaf-hoppers. Adults eat chinch bugs, beetles, crickets, caterpillars, etc. But they don't have the appetite you might expect for such a large and fierce-looking insect. Buy 16 egg cases per acre.
| Mite predator |
(Phytoseiulus persimils)
These are good at controlling two-spotted spider mites or red spider mites. Introduce predators only once a season. Two predators are needed for each infected plant, or two per leaf if the plant is large.
| Lady beetles |
Adult ladybugs eat 50-100 pests a day, including aphids, mites, scale insects, mealybugs, leaf-worms, leafhoppers, and stink bug eggs. Use 500 ladybugs to patrol an average garden; use 4000 per acre. Order in spring from a supplier. Lady beetles are very likely to wander if they are not carefully established in your garden.
| Aphid predator |
(Aphidoletes aphidimyza)
This is a predatory midge that feeds on the green peach aphid and other aphid species. Place at the foot of plants, five predators per sq. yd. repeat in two weeks for best results.
| Green lacewings |
Lacewings are among the best insect predators, because of their tendency to stay put in your garden. Lacewing larvae prey on aphids, red spider mites, thrips, mealybugs, and worm eggs. Release into the garden as eggs begin to hatch.
