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

• General Info
  • Protective screens or plastic. Reflective plastic mulches have been shown to reduce aphid infestations.
  • Augmentative releases of natural predators such as:
    • Hippodamia convergens (Convergent ladybug)
    • Parasitic wasps including Lysiphlebus testaceipe and Praon ssp.
    • Chrysoperla carnea (lacewing)
    • Orius tristicolor (minute pirate bug)
• Commonly Used Products
  • Ferti-Neem Oil
  • Ferti-Organics Karanja Oil
  • Biorepel (Garlic Oil)
  • Neemix 4.5 (Botanical)
  • Ecotrol Plus (Rosemary and other essential oils)
  • Soaps: Des-X
  • Sil-Matrix
  • Mycotrol ESO (Biological)
  • BoteGHA ES (Biological)

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