In the quest for the pest free garden, man has created an arsenal of potent chemicals to rid himself of these unwanted visitors. But there is an environmental as well as health-related price to pay for the indiscriminate use of pesticides. Little by little we accumulate residual quantities of these chemicals in places we don't want. That's why so many are sold now on the organic or natural approach.
For many gardeners, the number one ally in the fight against harmful insect pests is the beneficial insect. These guys are the one's that make a meal of the guys we don't want around. Some are tiny and some relatively large but the important thing they have in common is that they eat pest insects.
Here are some of them:
Parasitic wasps - these wasps lay their eggs on an insect's body. When the eggs hatch, the larvae use the insect host as food. They feed on a variety of destructive bugs such as whiteflies, caterpillars, moths, greenflies, and scale insects. The adults feed on nectar and pollen, so planting flowering plants will bring them to your garden.
Ladybug larvae - are rather ferocious, little insects that are spiny and black with bright spots on them. Although completely harmless to humans, they are voracious aphid eaters. Often when aphids appear on your garden plants, ladybugs and their larvae will show up shortly after and immediately begin to feed.
Dragonflies - while not strictly speaking predators of garden pests, they do love to eat mosquitoes, a pest in any case. They eat adult mosquitoes by capturing and eating them in the air, and eat mosquito larva in the water. Ironically, these excellent mosquito control agents, are sometimes victims of the spraying that some municipalities do to control mosquitoes. In the long run, this can have the effect of actually increasing the mosquito population as the dragonflies are killed off.
Prying mantises - are large, impressive insects, some of which look large enough to be mistaken for small animals. They have huge forelimbs with which they can snatch and hold a victim while devouring it (head first). While they certainly have their upside as beneficials, it's worth noting that these fellows don't limit their diet to only bad bugs. They'll eat pretty much any other insect, including each other. But since there are often way more undesirables that good guys, chances are they will fatten up on aphids, grasshoppers and the like.
Beneficial nematodes - are microscopic insects that eat cutworms, grubs, weevils, armyworms, and many, many other soil dwelling bugs. You'll probably have to order them from a supplier; many online dealers offer them. Once they arrive, just follow the directions in order to use them. They pose no threat to anything except the pest bugs that you don't want around.
Aphidoletes - are small flies whose larva feed on aphids by sucking the bodily fluids from them. They kill many more aphids than they eat. They bite them first to paralyze them with venom before eating them.
Pirate bugs - are small predatory bugs that eat a variety of pests including thrips, caterpillars, aphids and mites, as well as insect eggs. They are less than ¼ inch in length, and black with white markings. Both the adult and nymph stage are predators. They kill insects by piercing with their mouthparts and sucking out the body's fluids.
Lacewings - larvae are pest predators. The larvae are called aphid lions because of their voracious appetite. They pierce prey with mouthparts and suck out the juices. Adult lacewings are pollen feeders. The larvae also feed on mealy bugs, aphid eggs, spider mites, whiteflies, scale and thrips among others.
