Russian Wheat Aphid

Insect Summary Report

 

Diuraphis Noxia

 

General Information

  • Distinguished from all other aphids by cigar-like, spindle shaped body and terminal end that appears to be split at the tip when viewed with a hand lens.
  • In addition to extracting plant nutrients and excreting sticky sugar substance, this aphid also injects a salivary toxin that stunts growth, curls leaves and causes chlorotic and purple streaking. Infested flag leaf often results in hooked-shaped seed head.
  • Wheat and barley most susceptible. Rye, triticale and oats more resistant to infestation effects. Does not infest corn, sorghum or rice.
  • Often feed in the protection of curled leaves making contact insecticide use difficult.
  • Non-crop grass hosts include: volunteer wheat, wheat grasses, bromegrass, native rye, and jointed goatgrass. Grama grass and pearl millet may also serve as alternate hosts.
  • Not a vector of barely yellow dwarf virus.
  • During sexual reproduction, females release a sex pheromone that attracts males.

Life Cycle (9-55 Days)

  • Eggs… Produced by sexual reproduction.
  • Nymphs… 4-5 molts. Green.
  • Adults… Can produce as many as 5-6 live nymphs/day. Production slows dramatically as temps. approach freezing. Develop wings as crop and/or environmental conditions decline. Winged adults do not start reproducing until a new crop host is located.

Over-wintering Strategy

  • Proposed Treatment Thresholds
  • 2 Leaf – 5 per plant
  • Early Tillering – 5 per tiller
  • Late Tillering – 10 per tiller
  • 1st Node – 10 per tiller
  • Boot – 20 per tiller
  • Head – 30 per tiller

Organic Control

Cultural Control

  • Maintain good fertility, water moisture and mineral balance in plants. Identify macro- and micro- nutrient deficiencies by performing plant tissue and soil analysis. Adjust for deficiencies with foliar and soil applied applications of appropriate fertilizers.
  • Destroy sources of native grasses that serve as refuges for re-infestation.
  • Where possible, plant early to encourage seed head formation before aphid populations develop to a level that affects growth maturity and yield.
  • Maintain uniform stands.
  • Use high rates of control agents to avoid development of resistance.

 

More Images of the Russian Wheat Aphid

Bibliography

  • Images by Frank Peairs, Colorado State University, Bugwood.org (damage to seedheads of wheat, collection of predators, alatoid nymph, alate adult, discolored tillers, imported pests, and colony on wheat leaf)
  • Image by Phil Sloderbeck, Kansas State University, Bugwood.org (damage)
  • Images by Mary Burrows, Montana State University, Bugwood.org (symptoms and russian wheat aphid on winter wheat)
  • C. G. Summers, L. D. Godfrey, UC Davis/Kearney Agricultural Center, UC ANR Publication 3466. Feb. 2009. http://www.ipm.ucdavis.edu/PMG/r730300211.html (Damage, crop hosts, treatment thresholds, conventional controls, cultural control).
  • J. P. Michaud and Phillip E. Sloderbeck, Kansas State University, Russian Wheat Aphid. May, 2005.