Agriculture: Pear Pest Management Guidelines

Brown Mite

  • Bryobia rubrioculus
  • Description of the Pest

    The brown mite occasionally occurs on pears, and it may be the dominant mite on unsprayed trees early in the growing season. Like European red mites, brown mites overwinter in the egg stage. Eggs are red and spherical but do not have a stipe rising from the top. Newly hatched brown mites have six legs and are bright red. After they molt for the first time, they turn brown, develop eight legs, and resemble the adult, only smaller. Adult brown mites are dark reddish brown, and the first pair of legs is longer than the other three pairs.

    Damage

    Brown mite is a very minor pest in pear. Its feeding on foliage can produce a stippled appearance much like that caused by leafhopper feeding. Usually leaves do not turn brown or defoliate. If populations are heavy, stippled areas merge and the leaf takes on a pale look. Because brown mites spend most of the day on the wood of spurs and twigs, leaves closest to these parts are most heavily damaged. Feeding by brown mites is rarely severe enough to affect the fruit growth.

    Management

    Brown mites are usually the first mites to appear in spring. Dormant treatments of oil should keep them below damaging levels. Low levels in early spring are considered beneficial as a food source for mite predators. Additional treatments are seldom needed.

    Biological Control

    Biological control of brown mite is not as effective as it is for European red mite and webspinning spider mites. Predators include brown lacewings, green lacewings, minute pirate bugs, sixspotted thrips, and the spider mite destroyer lady beetle.

    Organically Acceptable Methods

    Biological control and approved oil sprays are organically acceptable methods.

    Monitoring and Treatment Decisions

    Monitoring guidelines have not been established for brown mite. Brown mite is best controlled in the dormant season or early foliage season. In-season sprays are rarely justified.

    Common name Amount to use** REI‡ PHI‡
    (Example trade name) (conc.) (dilute) (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.
     
    DORMANT
    A. NARROW RANGE OIL# 8 gal 2 gal 4 0
      . . . or . . .
      DORMANT FLOWABLE EMULSION 6–8 gal 2–3 gal 4 0
      . . . or . . .
      DORMANT PLUS 6–8 gal 3–4 gal 4 0
      MODE OF ACTION: Contact, including smothering and barrier effects.
      COMMENTS: Control improves the closer eggs are to hatching. For narrow range oil, check with your certifier to determine which products are organically acceptable.
     
    FINGER BUD TO PETAL FALL
    A. NARROW RANGE OIL# 4 gal 1 gal 4 0
      MODE OF ACTION: Contact, including smothering and barrier effects.
      COMMENTS: Check with your certifier to determine which products are organically acceptable.
       
    B. ABAMECTIN*
      (Agri-Mek 0.15EC) 10–20 fl oz 2.5–5 fl oz 12 28
      MODE OF ACTION GROUP NUMBER1: 6
      COMMENTS: Do not apply to blooming plants, including fruit trees and broadleaf weeds.
      . . . PLUS . . .
      NARROW RANGE OIL 0.25% minimum 1 gal 4 0
      MODE OF ACTION: Contact, including smothering and barrier effects.
     
    PETAL FALL TO HARVEST
    A. NARROW RANGE OIL# 4 gal 1 gal 4 0
      MODE OF ACTION: Contact, including smothering and barrier effects.
      COMMENTS: Check with your certifier to determine which products are organically acceptable.
    ** Dilute rate is the rate per 100 gal water; use 400 gal solution/acre. Apply concentrate in 80–100 gal water/acre, or less if the label allows.
    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.
    # Acceptable for organically grown produce.
    * 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: 11/12
    Treatment Table Updated: 11/12