Ladybugs
Praying Mantis
These spindly creatures may look scary, but they can be helpful to have around since they will devour any garden pest. The mantis' large front legs allow them to easily grasp prey such as mosquitos, beetles, aphids and crickets. However, their big appetites can have a downside: They will also eat other helpful insects like lacewings, ladybugs and hover flies, so it's important to keep their population under control.
Lacewings
These beautiful insects are one of the most beneficial to have in your garden. The lacewing's ability to effortlessly chow down on caterpillars, aphids, leafhoppers, whiteflies, mealybugs and insect eggs has earned it the nickname of "aphid lion." They're a favorite of home gardeners, since they're especially helpful at protecting roses and tomatoes.
Worms
These creepy crawlers might make you cringe, but they can be essential to a healthy garden. Worms make burrows that loosen the soil, letting air and water in and encouraging roots to grow. They also excrete organic matter that makes for a potent fertilizer. And there's strength in numbers: One acre of cultivated land may be populated by as many as 500,000 earthworms.
Hover Flies
Hover flies—also called flower flies or syrphid flies—are often mistaken for bees or wasps. They not only pollinate flowers, but they can also control aphids and other insects. Because they appear in early spring—well before most of the other "helpful" insects—they are credited with helping to produce excellent raspberry and strawberry crops.
Ground Beetles
While ground beetles aren't pleasant to look at (sorry), you should put out the welcome mat for these large non-pests. They're nocturnal and dig down into dirt and mulch to keep nighttime nuisances at bay. They feast on slugs, snails, cutworms and other garden pests, so the next time you see one crawling through your cabbages, resist the urge to step on it.
Wasps
You'll want to avoid their sting, but wasps can actually be a helpful in maintaining your vegetable garden. They are known to attack the eggs of various pests, and eat a lot of caterpillars and small white larvae that can destroy your vegetables. They're especially helpful for tomato plants, as they favor caterpillars that destroy the fruit.
