Predatory Bugs : Mirids

categories: Natural Enemies Predatory Bugs

last review date: 2025-09-13 04:23

Biology

Plant bugs or mirids are small (1/4 inch) and black or brown, similar to big-eyed bugs (without the bulging eyes). Some species are omnivorous feeding on plants as well as insect prey but rarely cause significant plant damage. Like big-eyed bugs they are long-lived and spend their time searching for mites, thrips, insect eggs, leafhoppers and small caterpillars on leaves, buds and flowers.

Deraeocoris brevis is the most common mirid seen in eastern Washington. It is oval, shiny black with paler markings, 1/10 to 1/5 inch long and approximately 1/12 inch wide. Nymphs are mottled whitish-gray with long gray hairs on the thorax and abdomen. A cottony secretion covers most of the body. Dark areas on the thorax and abdomen give it a spotted appearance. The eyes are dull red.

Deraeocoris overwinters as an adult in protected places such as under bark or in leaf litter. Overwintered adults emerge from hibernation during March to April and feed on nectar of willow catkins and other early spring flowers. They seek out prey and begin laying eggs in late April or May. Nymphs of the first generation occur two to three weeks later. Nymphs develop through five stages in approximately 25 days at 70 ºF.

Females lay up to 250 eggs during their lifetime and adults consume 10 to 20 aphids or mites a day. Nymphs can eat 400 mite eggs a day. Deraeocoris adults and nymphs prey on a wide variety of small insects and mites including aphids, thrips, leafhoppers, scale insects, small caterpillars, and spider mites.

Prey or Pest Targeted

• Mites, aphids, leafhoppers, thrips, caterpillars, mealybugs, beetles, scale insects, insect eggs

Attracting and Keeping Natural Enemies
and Pollinators in Your Yard and Garden

• Native plants provide essential resources.
• Native flora also provides natural overwintering sites.
• Natural dispersion from nearby habitats ensures visitation.
• Some kinds of beneficial insects predatory mites are commercially available.
• Avoid regular use of synthetic, broad-spectrum pesticides.
• Infrequent use of certain narrow-spectrum pesticides is more compatible with some beneficials.
• Extensive lawns are also not conducive to attracting beneficial insects.

Management Options

See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• None recommended