Two-Spotted and McDaniel Spider Mites

    Two-Spotted and McDaniel Spider Mites

    Tetranychus urticae; Tetranychus mcdanieli

    two-spotted spider mite

    Two-spotted spider mites and spherical eggs (Whitney Cranshaw, Colorado State University, Bugwood.org)

    spider mites

    Two-spotted mites (Frank Peairs, Colorado State University, Bugwood.org)

    spider mite damage

    Spider mite damage  (Whitney Cranshaw, Colorado State University, Bugwood.org)

    Pest Description

    • adults: very tiny, ~ 1/60 – 1/80 inch; greenish yellow
    • two-spotted: two black spots on back typically present
    • McDaniel: multiple pairs of black spots typically present
    • immatures: smaller and clear to yellowish
    • eggs: smaller than adults and are yellowish

    Host Plants, Diet & Damage

    • two-spotted: hundreds of plants are affected
    • McDaniel: typically found on fruit trees; many hosts
    • warm-season mites; prefer hot, dry weather
    • feed on plant cell contents
    • yellow/bronze stippling, leaf browning and dieback
    • may cause premature leaf drop and plant death
    • fine webbing on host plants; dirty appearance

    Biology, Life Cycle & Damaging Life Stage

    • overwinter as orange-colored females around host plants
    • egg laying begins once adults become active in spring
    • can disperse via wind
    • generation times are short: 1 to 3 weeks
    • overlapping life stages occur; many generations per year
    • immatures and adults are the damaging stages

    IPM Recommendations

    • Manage trees to improve or maintain health.
    • Monitor spider mite populations on host plants with a “paper test” starting in April. To conduct the test, hold a white sheet of paper under affected branches and shake vigorously. Tiny specks moving around on the paper indicate the presence of mites.
    • Preserve beneficial mites and organisms.
    • Spray top and undersides of plants with a stiff stream of water to disrupt mites (homeowner).
    • Apply an insecticide/acaricide (avermectin; dicofol; hexythiazox; horticultural oil; insecticidal soap; pyrethroid) when mites are present on plants.

    For more information, see our Web Spinning Spider Mites fact sheet.