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Top 10 Beneficial Garden Insects

Predators That Feed on Garden Pests

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A garden is a buggy place. Garden plants attract insect pests by the dozens, from aphids to slugs. But before you reach for an insecticide, take another look at the insects in your planting beds. While the pests are devouring your squash and tomatoes, another wave of insects is coming to the rescue.

Beneficial insects prey on the pests gardeners detest, keeping insect populations in check. You should learn to recognize these top 10 beneficial insects in your garden.

1. Green Lacewings

Green lacewing
Whitney Cranshaw, Bugwood.org

Most of the beautiful adult lacewings feed on pollen, nectar, and honeydew. Green lacewing larvae, however, are voracious predators. Nicknamed "aphid lions," the larvae do an impressive job of devouring aphids by the dozens. Larvae hunt for soft-bodied prey, using their curved, pointed mandibles to stab their victims.

2. Lady Beetles

Lady beetle larvae consume aphids by the dozens.
Photo: © Debbie Hadley, WILD Jersey

Everyone loves a ladybug, but gardeners hold them in especially high regard. Lady beetles eat aphids, scale insects, thrips, mealybugs, and mites – all the pests gardeners despise. With lady beetles, you get more bang for your buck, because both the adults and the larvae feed on pests. Lady beetle larvae look like tiny, colorful alligators. Learn to recognize them, so you don't mistake them for pests.

3. Assassin Bugs

Assassin bugs feed on a variety of pests, and some other beneficials, too.
Photo: Susan Ellis, Bugwood.org

Assassin bugs know how to take care of business. These true bugs use trickery, disguises, or just plain brute force to capture a meal. Many assassin bugs specialize in certain kinds of prey, but as a group, assassins feed on everything from beetles to caterpillars. They're fun to watch, but be careful handling them because they bite – hard.

4. Praying Mantids

Praying Mantid
Tim Santimore/Photolibrary/Getty Images

Contrary to popular belief, it is not illegal to harm a praying mantis. But why would you want to? Praying mantids can handle even the largest pests in the garden. You need a good eye to spot one, because their coloration and shape provide them with perfect camouflage among the garden plants. When the nymphs hatch, they're so hungry they sometimes eat their siblings. In fact, praying mantids are generalist predators, meaning they're just as likely to eat a helpful lady beetle as they are to catch a caterpillar.

5. Minute Pirate Bugs

Minute pirate bugs, tiny as they may be, do their part to keep aphids under control.
Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Arrgggh. You probably have minute pirate bugs in your garden, and don't even know it. Minute, indeed – these predators are tiny! Minute pirate bugs usually measure a mere 1/16th inch long, but even at that size, they can put away a good number of aphids, mites, and thrips. Next time you're in the garden, take a hand lens and search for them. Adults have black bodies with a white chevron pattern on their backs.

6. Ground Beetles

Ground beetle larvae feed on pests that live in soil.
Photo: Susan Ellis, Bugwood.org

You've probably overlooked the ground beetles in your garden. Lift a stepping stone, and you might see one skittering away. The dark-colored adults often have a metallic sheen, but it's really the larvae that do the dirty work of pest control. Ground beetle larvae develop in the soil, and prey on slugs, root maggots, cutworms, and other pests on the ground. A few species will venture up a plant stem and hunt for caterpillars or insect eggs.

7. Syrphid Flies

Syrphid fly larvae eat aphids by the dozens.
Photo: Flickr user Gilles Gonthier

Syrphid flies often wear bright markings of yellow-orange and black, and can be mistaken for bees. Like all flies, though, the syrphids have just two wings, so take a closer look if you see a new "bee" in your garden. Syrphid maggots crawl on garden foliage, searching for aphids to eat. They're quite good at squeezing in the curled up leaves where aphids hide, too. As an added bonus, the adults will pollinate your flowers. Syrphid flies are also called hover flies, because they tend to hover over flowers.

8. Predatory Stink Bugs

Not all stink bugs are beneficial, but some prey on other insects.
Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Though many stink bugs are plant pests themselves, some predatory stink bugs keep pests in check. The spined soldier bug, for example, feeds on caterpillars, sawfly larvae, and grubs. Most predatory stink bugs are generalist feeders, so they might also devour your lady beetles or even their own kin. You can recognize stink bugs by their shield-shaped bodies, and the pungent odor they produce when disturbed.

9. Big-Eyed Bugs

Tiny big-eyed bugs eat their weight in pests.
Photo: Jack Dykinga. USDA Agricultural Research Service

Predictably, you can distinguish big-eyed bugs from their closest relatives by looking at their large, bulging eyes. Like many other true bugs, their bodies are oval and somewhat flat. Big-eyed bugs are quite small, reaching an average of just 1/8th inches in length. Despite their diminutive stature, both adults and nymphs feed heartily on mites, aphids, and insect eggs.

10. Damsel Bugs

Damsel bugs look a bit like small assassin bugs.
Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Damsel bugs use thickened front legs to grab their prey, which includes aphids, caterpillars, thrips, leafhoppers, and other soft-bodied insects. Nymphs, too, are predators, and will feast both small insects and their eggs. With their dull brown coloring, damsel bugs blend in to their environment quite well. They look similar to assassin bugs, but are smaller.

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