Tarnished plant bug feeds on many flowers

The tarnished plant bug (Lyqus lineolaris) is a general feeder infesting many kinds of trees and herbaceous plants. It feeds on many flowers including aster, calendula, chrysanthemum, cosmos, dahlia, daisy, gladiolus, poppy, salvia, sunflower, verbena, zinnia and others.

Univ. of Mass. Extension reports that feeding by tarnished plant bug can result in injury to flower buds, causing them to abort and drop. The flowers may also not open properly or be distorted on one side. Other plant injury includes deformed leaves, scarred and discolored stems or leaf petioles.

It has a long piercing-sucking mouth part that is inserted into plant tissues. A toxic saliva is introduced into the plant as it feeds. The toxin kills cells near the feeding site causing growth distortion surrounding the piercing marks, yellow or brown spots or wilting of new growth. The heaviest injury often occurs during mid to late summer and is most evident during hot, dry weather, especially adjacent to recently cut hay fields.

The first few generations of the bug develop on preferred hosts such as small grains, alfalfa, wild grasses, vetch, dock and fleabane. As hay is cut or as other plants dry out, tarnished plant bugs migrate in large numbers to succulent hosts, which could be ornamentals.

Tarnished plant bugs can be difficult to manage due to their mobility. Besides insecticide spraying, the bug can be managed with cultural practices including the removal of weeds and the elimination of trash and other debris in areas that provide overwintering sites. Mowing grass and weeds around production areas may also help eliminate breeding sites. In weed-infested areas preventing young buds and flowers from forming can help to lower bug populations.