Host Plants:
On Crops: Many herbs and flowers, plus apples, pears, strawberries and peppers
Where Found:
Most of temperate North America
Description:
True plant bugs including four-lined plant bugs, tarnished plant bugs and a few other species are sometimes called mirid bugs, of which there are several thousand species. These small, slender insects are less than one-half inch (2cm) long, with markings that vary with species. In North America, you are likely to see passing damage from four-lined plant bugs on basil, mint, monarda, and many flowers. Four-lined plants bugs are so named because they have four black stripes down their yellow backs, with orange-yellow heads. Tarnished plant bugs are a mottled brown color. Apples and pears that are grown close to alfalfa, a host plant for tarnished plant bugs, may be damaged in early spring, when they are in bloom. Late in the season, tarnished plant bugs may damage peppers.
Damage:
These and other closely related species have sucking mouthparts, as do their tiny larvae. When four-lined plant bugs feed on leaves, they leave numerous small circular spots on tender new growth of herbs and flowers. Tarnished plant bug damage is similar, but the spots are more irregular in shape and pattern. Apple fruits that are misshapen, with deep pocks and folds, often were damaged at the blossom stage by tarnished plant bugs.
Preventing Problems:
In a diversified organic garden, four-lined plant bugs are kept in check by numerous natural predators including birds, frogs, wasps and spiders. Tarnished plant bugs can become a problem when they move into the garden from nearby fields. Use row covers to exclude them from garden crops.
Managing Outbreaks:
Both types of plant bugs drop to the ground when disturbed, so some can be collected in sheets of cloth spread beneath plants. Pinch off damaged stem tips from basil and other herbs.
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