Agriculture: Cole Crops Pest Management Guidelines

Springtails

  • Protaphorura fimata
  • Description of the Pest

    Springtails are minute, primitive, insectlike organisms. Their bodies are less than 0.1 inch (2.5 mm) long and wingless. Most springtails are harmless scavengers, and are considered beneficial organisms because they aid in the decomposition of decaying plant material. However, P. fimata has been found to cause problems in cole crops in the Salinas Valley.

    Most springtails have a forked appendage (furcula) at the tip of the abdomen, which they use to spring into the air when disturbed. P. fimata lacks a furcula and curls up when disturbed instead of jumping. It also lacks pigmentation and eyes.

    Springtails lay their round eggs in small groups in moist soil, especially where organic matter is abundant. The immature stage is usually whitish, and adults tend to be whitish, bluish, or lack pigmentation. The immature stage differs from the adult stage only in size and color.

    Damage

    Springtail damage to cole crops is currently a problem in various parts of the Salinas Valley and the Central Coast. They are often a problem in fields that contain a high amount of organic matter and fields that have a recent history of their presence, though their infestations do not always occur under these conditions. Damage more often occurs in the spring than during other seasons. Springtails will stunt seedling growth by damaging germinating seeds, roots and seedling leaves when present in large numbers. The seedlings may appear wilted and may die if damaged when young. Damage occurs as minute, rounded pits on young, developing leaves or roots, or as irregular holes in thin leaves. Mature plants are typically not significantly injured.

    Management

    Recent additions of organic matter (such as adding compost or incorporating a cover crop as green manure) as well as intensive irrigation (high soil moisture level for seed germination) can temporarily and dramatically increase springtail numbers.

    P. fimata can be mostly suppressed with early applications of synthetic insecticides directed at the seed line. An at-plant application of a pyrethroid, neonicotinoid, or spinosyn insecticide is often effective for both direct-seeded and transplanted cole crops. Seeds coated with a neonicotinoid insecticide targeted to manage other soilborne arthropod pests can also reduce springtail numbers.

    Monitoring and Treatment Decisions

    Monitoring is the key to determining the presence of springtails. There is currently no action threshold for springtails, but potato or beet slices can be used to monitor P. fimata presence or absence in the field. Determining whether or not springtails are present reduces unnecessary insecticide applications.

    1. Cut thin slices (about 0.5 inch) of beet root or potato (preferably of a darker color).
    2. Place the slices in the subsurface of the soil about 2 inches deep, and cover them with a plastic cover, such as white plastic bowls that are 3.5 inches in diameter and at least 1.5 inch deep.
    3. Assess the slices about 24 hours after deployment. (Slices tend to dry out when left in the field for longer periods of time, and thus become less attractive to P. fimata.)
    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.
     
    Seed Treatment
    A. CLOTHIANIDIN
      (NipsIt Vegetables) Label rates 12 NA
      MODE-OF-ACTION GROUP NUMBER1: 4A
      COMMENTS: Registered for use on only broccoli seeds in California, but seed treated in and obtained from another state can be legally used in California even if the chemical is not registered on the crop in California. Contact your retail seed dealer for information and availability. Application rate per seed depends on the amount of seed planted per acre.
     
    Directed Spray
    A. SPINETORAM
      (Radiant SC) 5–10 fl oz 4 1
      MODE-OF-ACTION GROUP NUMBER1: 5
     
    B. DINOTEFURAN
      (Venom) 5 oz 12 21
      MODE-OF-ACTION GROUP NUMBER1: 4A
      COMMENTS: Not registered for use on cole crops grown for seed. Rate above is for soil application. Registered for use on broccoli, broccoflower, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, and kohlrabi. Highly toxic to bees for more than 38 hours after application. This product has potential to leach into groundwater where soils are permeable, particularly where the water table is shallow.
     
    C. THIAMETHOXAM
      (Platinum) 5–11 fl oz 12 30
      MODE-OF-ACTION GROUP NUMBER1: 4A
      COMMENTS: Not registered for use on crops grown for seed. Thiamethoxam and its metabolites (which include the neonicotinoid clothianidin) are highly toxic to bees. This product has potential to leach into groundwater where soils are permeable, particularly where the water table is shallow.
     
    D. CLOTHIANIDIN
      (Belay) 9–12 fl oz 12 21
      MODE-OF-ACTION GROUP NUMBER1: 4A
      COMMENTS: Rate and PHI above are for soil application. Highly toxic to bees for more than 5 days after an application. This product has potential to leach into groundwater where soils are permeable, particularly where the water table is shallow.
     
    E. ZETA-CYPERMETHRIN
      (Mustang) 2.4–4.3 fl oz 12 1
      MODE-OF-ACTION GROUP NUMBER: 3A
      COMMENTS: In certain cole crops exported to Canada (broccoli, Brussels sprouts, cabbage, and cauliflower), PHI of 14 days is recommended in order to meet tolerances — see FIFRA 2(ee) recommendation for more information.
     
    F. LAMBDA-CYHALOTHRIN
      (Warrior II with Zeon Technology) 1.6 fl oz 24 1
      MODE-OF-ACTION GROUP NUMBER1: 3A
      COMMENTS: Registered for use on head and stem cole crops only (see label for more information).
     
    F. PYRETHRINS
      (PyGanic Crop Protection EC 1.4 II)# 16–64 fl oz 12 0
      MODE-OF-ACTION GROUP NUMBER1: 3A
      COMMENTS: Alternative to synthetic pyrethroids in organically grown cole crops. Check with organic certifier to determine which products are organically acceptable.
    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 the two intervals is the minimum time that must elapse before harvest.
    1 Rotate insecticides 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; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee).
    # Acceptable for use on organically grown produce.
    Text Updated: 12/20
    Treatment Table Updated: 12/20