Predatory bugs, including assasin bugs and minute pirate bugs, help control aphids, caterpillars, scale insects, spider mites and more.
Illustration By Keith Ward
This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides.
Assassin Bugs (Hemiptera) and Other Predatory Bugs
Active pest hunters, predatory bugs have shield-shaped backs typical of true bugs. Some of the most important species include big-eyed bugs, minute pirate bugs, assassin bugs, damsel bugs and even certain predatory stink bugs. All predatory bugs use their mouth, or “beak,” to pierce and consume prey by sucking them dry. Adults range in size from the minute pirate bug (one-sixteenth-inch long) to the wheel bug (an assassin bug that’s 1 1/2 inches long).
Big-eyed bugs, assassin bugs and minute pirate bugs overwinter as adults in weedy areas or among shrubs, and emerge in late spring. They promptly mate and begin laying eggs where aphids, caterpillars or other food is abundant. Immature nymphs are often more colorful than their parents. Both young and mature big-eyed bugs, assassin bugs and other predatory bugs consume a wide variety of other insects in the garden.
What Do Assassin Bugs Eat?
Assassin bug nymphs or larvae and adults feed on aphids, caterpillars, scale insects, spider mites and insect eggs. Many also prey upon beetles. Assassin bugs are among the few natural predators that eat and help control Mexican bean beetles. Minute pirate bugs consume and help control corn earworms before they can infiltrate ears.
How to Attract Predatory Bugs
Do not touch or handle any of the bugs on this list, because they are capable of biting when alarmed. Avoid using garden pesticides, which can devastate populations of these beneficial insects. Predatory bugs are always most numerous late in the season.
More information on big-eyed bugs, assassin bugs and other predatory bugs is available from Utah State University, Ohio State University, and the University of Wisconsin.