Tarnished Plant Bug (TPB)

Lygus lineolaris

Written by: 

Jaime Pinero

Overview

Several species of insects with piercing-sucking mouthparts that feed on peaches early in the growing season can cause a gnarling and distortion of the fruits called catfacing. Fruit is deformed because areas around feeding sites grow more quickly than the damaged parts. Early-season feeding damage from TPB causes raised and sunken corky areas free of fuzz on the surface of the peach fruit. Late-season feeding results in stings with gummy ooze.

TPB is one of several bugs (order Hemiptera) that can produce fruit catfacing. TPB feed on a wide range of crops. TPB is most often a problem in fruit orchards with ground cover comprised of broadleaf weeds, or in orchards near alfalfa fields or other host plants.

TPB adults are about ¼ inch long, oval, and somewhat flattened. Color ranges from green to dark brown, flecked with white, yellow, reddish brown, and black markings. Nymphs (immature stages) are pale yellow to green. Mouthparts are the piercing-sucking type; the beak is three- or four-segmented, arises on the front of the head, and is held below the body, between the legs, when not in use. Nymphs are generally similar to adults but do not have wings.

Biology

TPB overwinter as adults in leaf litter, plant debris, and brush piles, and move to broadleaf weeds, grasses and crops to lay eggs in the spring. TPB adults are strongly attracted to orchards with winter annual weeds in bloom. The nymph is pale yellow or green. It resembles the adult but is smaller and has no wings. It develops through five instars. The third to fifth instars have distinct spots on the thorax and abdomen. The fourth and fifth instars begin to develop brown pigment and larger wings resembling the adult TPB.

Monitoring

White sticky traps are available for monitoring TPB adults. White cards are hung out about two feet from the ground from an outer branch at silver tip and checked preferably twice a week. Traps (one per three to five acres) should be placed at the edge of the block. The economic threshold s 2.4 TPB per trap by tight cluster and 4.1 per trap by late pink. Monitoring in peaches and nectarines is critical at petal fall to shuck fall.

Management

When trees are at the vegetative stage, low densities of TPB can be tolerated. As the trees begin to set buds, chemical controls may be needed. On stone fruits, insecticide applications at petal fall, shuck fall, and 10 days after shuck fall typically provide good control. Applications during pink are often unnecessary because most fruit injured at this time aborts. In comparatively larger blocks, border rows can reduce TPB numbers and level of damage.