Tarnished Plant Bug

Tarnished Plant Bugs are also known as Lygus bugs. The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is in the order Hemiptera, family Miridae.

Description

The adult is a small insect, about 1/4" in length. It is light brown and variously spotted. The white, yellow, and black spots give the insect a tarnished appearance, but there is a clear yellow triangle, marked with a black dot on the lower third of each side. The young tarnished plant bugs, called nymphs are similar to the adults except they have wing pads.

Common Host Plant(s)

Strawberries, vegetables, tree fruits, and flowers (dahlias, chrysanthemums, marigolds, zinnia, and many others).

Damage

Adults emerge in the spring and attack swollen overwintering buds on trees and shrubs. This causes leaf deformities and debudding, which ultimately can lead to bushiness. Shoots may be distorted or stunted if the attack occurs after shoot elongation. Later in the growing season, all life stages will be present and feeding. On flowers, nymphs and adults puncture the terminal shoots beneath the bud and inject a poison, which usually causes the flower to wilt and die. On leaf buds, feeding causes spotting and a general bronzing effect on the leaves. A condition called catfacing can occur on tree fruits and vegetables when the tarnished plant bug feeds on the developing fruit. Damage when the fruit is small can cause the fruit to be deformed and misshapen when it reaches maturity, thus catfaced. The fruit may also be aborted and drop to the ground if it is too heavily damaged. The feeding damage on strawberries is called "buttoning".

Lifecycle

The adults and older nymphs hibernate under leaf litter and rocks. These individuals become active during the first warm days of spring. They feed on early buds of their host plant, but breed in grasses. Eggs are generally laid on the midrib of leaves and sometimes are inserted into the plant buds. Ten days later, the eggs hatch. The nymphs usually remain on the plant upon which they hatch, but may move to adjacent plants. The adults have wings and readily move from weeds to fruit trees.

Control

Some varieties may be resistant to attacks by tarnished plant bug, particularly fruits with many plant hairs. Check the Virginia Pest management Guide for current chemical control recommendations for the tarnished plant but and other bugs. Insecticide treatments probably are only partially effective. Plant bugs are active and
move about freely, thus avoiding the treatment. Feeding injury can resume as soon as the effectiveness of sprays dissipates.

Remarks

Minor plant bug injury is tolerable, although unsightly. Controls are necessary for severe infestations.