Russian Wheat Aphid

Diuraphis noxia

The Russian wheat aphid arrived in the Great Plains in 1986 and caused serious economic losses in wheat across the High Plains for about 10 years, before receding in importance as biological controls, aided by resistant cultivars, became more effective. More recently, significant infestations in Kansas have generally been limited to the counties near the Colorado border and in the southwest corner of the state.

This small, lime-green aphid has a football-shaped body and very short cornicles, legs, and antennae. These aphids prefer to feed on the newest growth of the wheat plant, rolling up the leaves to create a protected microhabitat. Resistant varieties are less prone to leaf rolling, leaving the aphids more exposed to predation and parasitism. Infested leaves exhibit purple, yellow or white longitudinal streaks along the leaves and leaf sheaths. Heavily infested plants may appear flattened, with young tillers lying almost prostrate to the ground.

Russian wheat aphid damage.

High populations of Russian wheat aphids that persist for long periods can lead to serious crop losses. Risk of yield loss is highest when infestations develop in early spring. Fortunately in Kansas, climatic conditions and biological control by predators, are normally quite effective in keeping them below damaging levels.

Management

The recommended threshold for treatment varies with the expected yield. Populations that develop soon after the crop emerges in early fall can be damaging but are unusual in Kansas. At this time, a 20 to 30 percent infestation of plants or tillers may warrant treatment. In spring, if wheat has a yield potential of at least 20 bushels per acre, treatment should be considered when 20 percent of tillers show symptoms and most have live aphids. In fields with a yield potential of 40 bushels or more, it may be economical to treat when as few as 10 percent of tillers are infested. When 30 to 40 percent of primary tillers are infested anytime between flowering and the soft dough stage, treatment may be advisable, but infestations confined to late-developing secondary tillers are less damaging to yield. In areas with a history of Russian wheat aphid problems, resistant varieties are a potential management option, although biotypes of the pest have evolved that have broken the older sources of resistance present in some varieties. Seed treatments with neonicotinoids will protected seedlings from Russian wheat aphid and all other wheat aphids. Some seed treatments carry the warning to not graze or feed livestock in treated areas for 45 days after planting.

More information on the biology and life history of the greenbug can be found in KSRE publication MF2666 Russian Wheat Aphid.

Please refer to the most recent version of the Wheat Insect Management Guide for control options.

Page last updated 06/06/2024 by J.P. Michaud.