Tarnished Plant Bug (TPB)

Lygus lineolaris

Overview

TPB feeding up to tight cluster usually results in aborted fruit. Buds fed on from Tight Cluster through Bloom may be scarred. As apple develops, damage appears as deep, sunken areas, conical in shape, with associated light corky russetting. Damage is often confined to fruit calyx.

Biology

• TPB adults are 1/4 inch long, somewhat flattened and brown in color, with black, white, or yellow markings, including a clear-yellowish triangle on each wing tip.
• Adults overwinter in protected areas within and around orchards. They are first active on warm early spring days and become abundant from green tip through petal fall. Adults feed by inserting their mouthparts into developing fruit buds. Orchards with an abundance of legumes or flowering plants in the ground cover often have high TPB populations.
• TPB feeding up to Tight Cluster usually results in undeveloped buds that fail to set fruit. Buds damaged by feeding after tight cluster may survive but will be scarred. As the apple develops, damage often appears as deep, sunken areas, conical in shape, with associated light corky russetting, often confined to fruit calyx.

Monitoring

• TPB adults can be monitored using a visual, white sticky trap set at silver tip. Traps should be stapled to stakes or hung on low branches no higher than knee height near orchard perimeter. Use at least one trap per 3 acres and at least 3 traps per monitored block. Action threshold is cumulative average of 5 TPB per trap by Tight Cluster or 8 TPB by Pink.
• Examine 10 terminals per block for bleeding buds. Action threshold is 2-3 bleeding sites per 10-terminal sample.
• TPB activity is highly dependent on temperature, so that 2 or 3 days of warm (50-60 degrees), sunny weather triggers increased foraging and feeding behavior.

Management

• If needed, apply insecticide Tight Cluster to Pink bud stage. Use of synthetic pyrethroids may lead to outbreak of European red mites since these insecticides are harmful to beneficial mites.
• Control may be enhanced by spraying insecticide on a warm, sunny, calm day when TPB are most active.
• Destroying broad leaf weed hosts in and around the orchard in the fall may decrease overwintering TPB.
• Avoid mowing or using herbicide between Pink and Petal Fall because disturbance of alternate hosts in the groundcover may cause TPB to move into apple trees.