Two-Spotted and McDaniel Spider Mites
Tetranychus urticae; Tetranychus mcdanieli
Two-spotted spider mites and spherical eggs (Whitney Cranshaw, Colorado State University, Bugwood.org)
- 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
- 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.