Agriculture: Small Grains Pest Management Guidelines

Bird Cherry-Oat Aphid

  • Rhopalosiphum padi
  • Description of the Pest

    Key to identifying aphids

    Bird cherry-oat aphid is the most common aphid found on cereals. Its color ranges from orange green to olive green to dark olive green, and sometimes greenish black. It has long antennae and long tube-shaped cornicles arising from the side of the abdomen near the rear end. Wingless forms frequently have a reddish orange patch around the base of the cornicles. Bird cherry-oat aphid may be found any time after seedling emergence but is most common in February and March. The bird cherry-oat aphid is most easily confused with the corn leaf aphid but the former has a rounded, bulblike body shape while the latter appears almost rectangular.

    Damage

    Bird cherry-oat aphid attacks all small grains including wheat, barley, oats, rye, and triticale. It may also be found on sorghum and corn. Heavy populations may cause a golden yellow streaking on the leaves; do not confuse this with the white streaks caused by Russian wheat aphid. Occasionally heavy populations cause the flag to curl up in a tight corkscrew fashion that may trap the awns, resulting in a fish-hook appearance to the head. Leaf curl caused by the bird cherry-oat aphid resembles a corkscrew, while that by the Russian wheat aphid resembles an upright soda straw.

    Bird cherry-oat aphid is a vector of BARLEY YELLOW DWARF virus.

    Management

    Biological Control

    Bird cherry-oat aphid populations are usually kept under control by a combination of predators and parasites (see APHIDS – GENERAL CONSIDERATIONS). Before considering chemical controls, evaluate the activity and control potential of these natural enemies.

    Cultural Control

    Bird cherry-oat aphid can build up on volunteer cereals; destroy these plants before newly planted crops emerge to help reduce aphid numbers.

    Management Decisions

    Economic thresholds for bird cherry-oat aphid are not well established. Do not consider treatment until the number of aphids exceeds 50-60 per tiller. Chemical controls should then be applied only if there is no evidence of natural enemy activity or if the plants are several weeks from flowering.

    Common name Amount per acre REI‡ PHI‡
    (Example trade name) (hours) (days)
    Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used.
     
    A. DIMETHOATE
      (Dimethoate 4EC) 0.5–0.75 pt 48 35
      MODE-OF-ACTION GROUP NUMBER1: 1B
      COMMENTS: For use on wheat and triticale only. Do not make more than two applications per year. Do not graze within 14 days. Highly toxic to honey bees if bees are present at treatment time or within a day after. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
     
    B. MALATHION
      (Malathion 8) 1 pt 12 7
      MODE-OF-ACTION GROUP NUMBER1: 1B
      COMMENTS: May be used on wheat, barley, oats, and rye. If alfalfa is in bloom, apply during the night or early in the morning when bees are not foraging in the field. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
    Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI; the longer of these two intervals is the minimum time that must elapse before harvest may take place.
    * Permit required from county agricultural commissioner for purchase or use.
    1 Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee).
    Text Updated: 02/09
    Treatment Table Updated: 07/16