Pacific Northwest Insect Management Handbook

Field and silage corn-Aphid

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Image related to Field and silage corn-Aphid
Corn leaf aphid
Rhopalosiphum maidis Fitch
© Ken Gray Insect Image Collection
Image related to Field and silage corn-Aphid
"oat bird-cherry" aphid
Rhopalosiphum padi Linnaeus
Female adult
© Ken Gray Insect Image Collection
Image related to Field and silage corn-Aphid
"oat bird-cherry" aphid
Rhopalosiphum padi Linnaeus
© Ken Gray Insect Image Collection

Includes

Bird-cherry oat aphid (Rhopalosiphum padi)
Corn leaf aphid (Rhopalosiphum maidis)

Pest description and crop damage Green and black aphids suck sap. They may become very abundant, especially later in the season. Large populations of aphids may reduce kernel number and size.

Management-chemical control

  • abamectin/thiamethoxam (Avicta Duo Corn)-Apply as slurry to corn seed. Consult label.
  • alpha-cypermethrin (Fastac CS) at 0.017 to 0.025 lb ai/a. REI 12 hr. PHI 30 days grain and stover; 60 days forage. Retreatment interval 3 days. Do not exceed 0.075 lb ai/a per season.
  • azadirachtin (Aza-Direct) at 16 to 32 oz formulated product/a. PHI 0 days. REI 4 hr. Some formulations are OMRI-listed for organic use.
  • Beauveria bassiana (Mycotrol ESO) at 4 oz/acre. REI 4 hr. PHI 0 day. OMRI-listed for organic use.
  • bifenthrin (Brigade 2EC) at 0.033 to 0.1 lb ai/a. PHI 30 days for harvest, grazing, or cutting for feed. REI 12 hr. Do not apply more than 0.3 lb ai/a per season.
  • bifenthrin/zeta-cypermethrin (Hero EW) at 0.04 to 0.1 lb ai/a. PHI 30 days grain and stover; 60 days forage. REI 12 hr. Do not graze for 30 days after treatment. Do not exceed 0.4 lb ai/a per season.
  • chlorantraniliprole/lambda-cyhalothrin (Besiege) at 0.052 to 0.086 lb ai/a (suppression only). PHI 21 days. REI 24 hr. Do not exceed 0.12 lb ai of lambda-cyhalothrin or 0.2 lb ai of chlorantraniliprole per acre per growing season. Retreatment interval 7 days.
  • chlorpyrifos (Lorsban Advanced) at 0.47 to 0.8 lb ai/a. PHI 21 days before harvest of grain or ears. Limit 3 applications. REI 24 hr. Apply as a postemergence broadcast spray or through overhead sprinklers. Do not exceed 3 lb ai/a per season for all chlorpyrifos treatments. RESTRICTED USE IN OREGON.
  • Chromobacterium subtsugae (Grandevo) at 0.6 to 0.9 lb ai/a per 100 gal. PHI 0 days. REI 4 hr. OMRI-listed for organic use.
  • dimethoate (Dimethoate 400) at 0.33 to 0.5 lb ai/a. PHI 14 days forage; 28 days grain. REI 48 hr. Do not exceed 0.5 lb ai/a per season. Do not apply during pollen shed if bees are foraging actively.
  • esfenvalerate (Asana XL) at 0.03 to 0.05 lb ai/a. PHI 21 days. REI 12 hr. Do not exceed 0.25 lb ai/a per season.
  • flupyradifurone (Sivanto 200SL) at 0.09 to 0.14 lb ai/a. PHI 7 days forage; 21 days grain, stover or straw. REI 4 hr. Retreatment interval 7 days. Do not exceed 0.365 lb ai/a per season.
  • malathion (Fyfanon 8, Gowan Malathion 8) at 0.6 to 1 lb ai/a. PHI 7 days. REI 12 hr. Limit 2 treatments per year. Retreatment interval 7 days.
  • methomyl (Lannate SP) at 0.22 to 0.45 lb ai/a. PHI 21 days for ears, 3 days for forage, or 21 days for fodder. REI 2 days. Do not exceed 2.25 lb ai/a or 5 treatments per season. Retreatment interval 5 to 7 days.
  • sulfoxaflor (Transform WG) at 0.023 to 0.047 lb ai/a. PHI 14 days for grain or straw. Do not apply more than 0.09 lb ai of sulfoxaflor per acre per year.
  • tebuconazole/lambda-cyhalothrin (Crossover) at 0.14 to 0.16 lb ai/a. PHI 21 days fodder and silage. REI 24 hr. Retreatment interval 7 days. Do not exceed 0.48 lb ai/a tebuconazole or 0.12 lb ai/a lambda-cyhalothrin per season.
  • zeta-cypermethrin (Mustang) at 0.034 to 0.05 lb ai/a. PHI 7 days for grain, stover and forage. REI 12 hr. Do not exceed 0.2 lb ai/a per season. Retreatment interval 3 days.

Kaur, N. (Ed.). 2023 Pacific Northwest Insect Management Handbook.
© Oregon State University.

Use pesticides safely!

  • Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
  • Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
  • Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.

Trade-name products and services are mentioned as illustrations only. This does not mean that the participating Extension Services endorse these products and services or that they intend to discriminate against products and services not mentioned.