Tarnished Plant Bug

species: lygus lineolaris (palisot de)
common names: tarnished plant bug
hosts:
notes:

Agriculture and Agri-Food Canada Insect Identification Sheet No. 59 March 1981 Tarnished Plant Bug Lygus lineolaris (Palisot de Beauvois) The tarnished plant bug is found across Canada. It attacks a wide variety of plants including alfalfa, beans, beets, celery, peppers, potatoes, cucumbers, strawberries, tomatoes, tobacco, turnips, peaches, apples and pears.

Injury:

Host plants are attacked by both adults and nymphs, although most of the serious damage is caused by the maturing nymphs. Tarnished plant bugs feed by sucking the plant sap. As they feed, a toxic saliva is introduced into the plant, causing distortion, drop of terminal buds, wilting, stunting and dieback. Heavily infested alfalfa fields blossom normally, but drop their flowers prematurely and developing seeds shrivel and fail to mature. The tarnished plant bug also feeds on fruits causing pitting and a partly peeled appearance commonly called 'catfacing'.

Life History:

Tarnished plant bugs overwinter in the adult stage under bark or leaf litter. Adults are small (6 mm long) oval insects that vary from straw green to dark brown, with yellow, reddish-brown and black mottling. Adults are very active, quickly flying away when disturbed. They emerge early in the spring, feeding on weeds and fruit buds. After mating, the females insert the elongate, slightly curved eggs into the stems or petioles of weeds, alfalfa or vegetables. Within 10 days, the small (1 mm long) yellowish-green nymphs emerge. Undergoing five molts, they become adults within 3-4 weeks. In Canada, there is one or possibly two generations per year, depending on locality. In all areas there is an overlapping of generations so that all stages may be present at the same time.

Pest Management:

The tarnished plant bug is a serious pest of cultivated crops. Burning of weeds and trash near crop areas will reduce pest numbers. Contact your provincial agricultural representative for control recommendations.

Written under contract to the BC Ministry of Environment, Lands and Parks (now Ministry of Water, Land and Air Protection) by: D.E. Henderson, E.S. Cropconsult Ltd., Vancouver, British Columbia in collaboration with D.A. Raworth, Research Station, Vancouver, British Columbia:

Lygus bug and other plant bugs (Hemiptera: Miridae)

Plant bugs include the lygus bug (tarnished plant bug), stink bug, cinch bug, and others. Most plant bugs overwinter as eggs, but a few hibernate as adults under debris in the field. In the spring, eggs hatch or adults become active and lay eggs. Lygus nymphs resemble large aphids — delicate, usually green, and without fully developed wings. Nymphs run quickly when disturbed. They go through five stages or molts in about 5 weeks and feed on plant juices during each stage, as well as when they are adults. Feeding on the flower blossoms causes uneven pollination, which results in "cat facing" in strawberries and "crumbly berry" in raspberries. Adults have characteristic markings on their backs and carry their long, pointed, sucking mouthparts folded under their bodies. When disturbed, they fly or ran and hide.

Not all plant bugs are harmful; some are predators. Of the five bug species found on strawberry crops, all feed on plants but one will also feed on other insects. Of the 22 species found on raspberry crops in Canada, 6 are plant feeders, 10 are predators, and 6 will feed both on plants and on insect prey.

Lygus bugs are parasitized by a number of braconid wasps, at least one ichneumonid wasp, and several tachinid flies. Many insects have been recorded as predators of lygus bugs especially damsel bugs, bigeyed bugs, other plant bugs, and lacewings but little is known about how important they are. In general, these predators prefer soft-bodied prey but will also feed on lygus bugs, especially the young nymphs.