The adult tarnished plant bug is a 1/4-inch-long, oval, flat, brownish insect, mottled with yellow and black. It sucks on plant parts. The tarnished plant bug’s eggs are long and curved, and can be found inserted in stems, tips, and leaves. The nymphs are pale yellow.
It is difficult to control because it is highly mobile, secretive, and feeds on many species of wild and cultivated plants. Adults and nymphs inject poison into young shoots, flower buds, and fruits when puncturing cells to suck juices. Nymphs are pale yellow and the eggs are elongate, curved and inserted in stems, tips, and leaves. The tarnished plant bug also carries fire-blight disease, infecting trees as they feed.
Adults fly to fruit trees in the first warm days of spring. They feed on develoceping buds, immediately halting fruit development. Only buds that escape feeding will set fruit. On dwarf trees this can totally eliminate fruit production. Later feeding damage usually appears as a dimple or a scab. Tarnished plant bugs cause leaves and shoots to die on trees. On strawberry, pear, and peach, they dwarf fruit and create sunken areas (called cat-facing).
VULNERABLE PLANTS
Most vegetables including celery, chard, lima beans, and snap beans. Strawberries, and fruit trees, including pear and peach.
MOST OBVIOUS SYMPTOMS
Black spots and pitting can be seen on the stem tips, buds, and fruit of infested pear trees when these pests are present. Tarnished plant bugs are highly mobile. They deform roots, blacken terminal shoots, and ruin flowers. Only buds that escape feeding will set fruit.
CONTROLLING TARNISHED PLANT BUG
EARLY WARNING DEVICES
One type of early warning trap is made from and 8- by 10-inch white panel covered with a sticky substance. These are available commercially or can be made at home. Tarnished plant bugs are attracted to white and are active around orchards during bloom time. Hang the panels from the outer branches of your fruit trees, 2 1/2 feet above the ground. Clear any foliage within 18 inches of the panel to increase visibility. If you make your own traps, use a glossy white paint, which will reflect light in the same way that an apple blossom does. In the vegetable garden place them adjacent to, not above, susceptible plants.
TRAPS AND MECHANICAL CONTROLS
If large enough or used in large enough numbers, sticky traps can be used as control devices for tarnished plant bugs as well as be early warning devices for them. Make 10-inch square panels from a bright white material such as Masonite and coat them with sticky material such as Tanglefoot, motor oil, or petroleum jelly. In the vegetable garden place them adjacent to, not above, susceptible plants. In the orchard hang them 2 1/2 feet above the ground.
Natural Insecticides
Use sprays early in the morning when bugs are least active.
PYRETHRUM
Pyrethrum will kill tarnished plant bugs, but when they are very abundant spraying has little effect on the population. Try three applications 2-3 days apart.
