Agriculture: Dry Beans Pest Management Guidelines

Aphids

  • Bean aphid: Aphis fabae
  • Cowpea aphid: Aphis craccivora
  • Green peach aphid: Myzus persicae
  • Pea aphid: Acyrthosiphon pisum
  • Description of the Pest

    Aphids are small insects, 0.04 to 0.2 inches (1–5 mm) long that come in a variety of colors. The two most common species encountered on beans are the cowpea aphid and the bean aphid.

    • The adult cowpea aphid has a shiny black body with whitish legs and antennae ending in black tips, while the younger cowpea aphid nymph is a lighter gray.
    • The bean aphid is slightly larger and less shiny than the cowpea aphid. The adult bean aphid is dark purplish-black with light-colored legs, while the younger bean aphid nymph has a slightly reddish tint.
    • The pea aphid is a relatively large (4 mm), green, long-legged aphid.
    • The green peach aphid is dark green to yellow and lacks a waxy covering.

    Refer to the photo identification key, Key to the common aphids of cowpeas in California (PDF) for more detailed information.

    Damage

    Ways that aphids damage plants:

    • Suck plant sap which stunts plants and causes heavily infested leaves to curl
    • Excrete honeydew, a sugary substance that causes sticky, shiny leaves and black sooty mold growth
    • Spread plant diseases (a large number of viruses are vectored by aphids)
    • Inject toxins which can stunt plants

    Infestations are frequently localized with heavily infested leaves curled downward.

    Management

    Assess levels of biological control when evaluating aphid numbers. Frequently, natural enemies prevent aphid infestations from becoming established throughout a field. Temperatures greater than 85°F can slow down increase of pea and green peach aphid numbers.

    Biological Control

    (View photos to identify natural enemies of aphids)

    Common predators of aphids in beans include lady beetles, syrphid flies, and lacewings. Parasitic wasps also attack aphids, turning them into hard, aphid-shaped shells called mummies. Plant field edge habitat that attracts natural enemies and avoid the use of broad-spectrum pesticides known to harm natural enemies.

    Organically Acceptable Methods

    Planting hedgerows of native California flowering shrubs along field crop edges will enhance natural enemy activity, helping to manage this pest. For more information about planting hedgerows, see Establishing Hedgerows on Farms in California, (PDF) UC ANR publication 8390. Organically approved pesticides are not likely to provide economically viable levels of pest control in dry bean production.

    Monitoring and Treatment Decisions

    Aphid control in beans is not always necessary. The decision to apply an insecticide for aphids is based mainly on visual inspection and the stage of crop development. Measurable thresholds are not available. Begin inspecting for aphid problems when the crop emerges. Continue monitoring through the vegetative growth and flower bud to bloom stages. Apply an insecticide to seedling plants if they appear to be stressed by aphid populations. Older plants can tolerate low to moderate numbers of aphids.

    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. FLUPYRADIFURONE
      (Sivanto) 7–10.5 fl oz 12 7
      MODE-OF-ACTION GROUP NUMBER1: 4D
     
    B. MALATHION
      (Fyfanon ULV AG) 8 fl oz 12 1
      MODE-OF-ACTION GROUP NUMBER1: 1B
      COMMENTS: Do not graze livestock in treated areas or harvest vines for forage or hay.
     
    C. DIMETHOATE
      (Dimethoate 2.67) 0.75–1.5 pt 48 0
      MODE-OF-ACTION GROUP NUMBER1: 1B
      COMMENTS: Do not feed sprayed vines to livestock. Not registered for cowpea.
     
    D. IMIDACLOPRID
      (Admire Pro) 7–10.5 fl oz (soil), 1.2 fl oz (foliar) 12 21 (soil), 7 (foliar)
      MODE-OF-ACTION GROUP NUMBER1: 4A
     
    E. BIFENTHRIN/IMIDACLOPRID
      (Brigadier) 3.8–5.6 fl oz 12 14
      MODE-OF-ACTION GROUP NUMBER1: 3A/4A
     
    F. BETA-CYFLUTHRIN/IMIDACLOPRID
      (Leverage 360) 2.4–2.8 fl oz 12 7
      MODE-OF-ACTION GROUP NUMBER1: 3A/4A
      COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
     
    G. LAMBDA-CYHALOTHRIN
      (Warrior II with Zeon) 1.28–1.92 fl oz 24 21
      MODE-OF-ACTION GROUP NUMBER1: 3A
      COMMENTS: Do not graze livestock in treated areas or harvest vines for forage or hay.
     
    H. BIFENTHRIN
      (Bifenture EC) 2.1–6.4 fl oz 12 14
      MODE-OF-ACTION GROUP NUMBER1: 3A
     
    I. ZETA-CYPERMETHRIN
      (Mustang Maxx) 3.2–4.0 fl oz 12 21
      MODE-OF-ACTION GROUP NUMBER1: 3A
     
    SEED TREATMENTS
     
    A. THIAMETHOXAM
      (Cruiser 5FS) 1.28 fl oz per 100 lbs seed NA NA
      MODE-OF-ACTION GROUP NUMBER1: 4A
    ** Mix with sufficient water to obtain full coverage.
    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 two intervals is the minimum time that must elapse before harvest.
    1 Rotate pesticides 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; pesticides with a 1B group number should be alternated with pesticides that have a group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee).

    Important Links

    Text Updated: 06/18
    Treatment Table Updated: 06/18