Every gardener is familiar with a few beneficial insects, such as ladybugs. Few are aware of what the life stages of these insects look like and that mites, true bugs, and wasps are important biological control agents in the garden.
Everyone knows what a ladybug looks like, but few recognize the eggs, larvae, or pupal cases that precede the insect's adult stage. Several species are found in North America. The imported Asian ladybug has become especially common in recent years.
Adult ladybugs are often sold in garden centers or by mail order. They are collected from locations where they gather to wait out the hottest part of summer and are refrigerated until sold, then sent to a retail outlet or your doorstep. It is difficult to keep them in the garden they're released into because they often fly long distances to get back to the breeding areas from which they were collected. It's better to rely on local populations of ladybugs.
Not all mites are pests. Some, such as the predatory mite, might be present in the garden without your knowing it. When you are doing a beat test to detect mites and small insects on your plants, you might see a few predatory mites moving rapidly across the paper. They are more translucent than pest mites and have longer legs that allow them to move faster than their prey.
Also known as flower flies and hover flies, syrphid flies are important predators of aphids and mites. They look like bees or wasps, but their large eyes and single set of wings set them apart from the bees and wasps they mimic. Syrphid flies can usually be found hovering near daisy- or carrot-family flowers. Larvae, right, devour aphids and other pests.