Two-Spotted Spider Mite Management on Mature Junipers/Cedars

Fifteen 20-year-old upright cedars/junipers in western Kansas show increasing damage despite spraying. Owner seeks better control.

Mite Biology

• Not insects—arachnids with piercing mouthparts.
• Feed on sap → stippling (tiny yellow spots), needle browning, drop.
• Peak populations in spring and fall (cool weather); crash in summer heat due to predators.
• Heavy infestations show fine webbing.

Monitoring Threshold

Hold white paper under a branch, strike sharply. Dozens of mites per strike = damaging population. Check weekly.

Homeowner Miticides

• Insecticidal soaps (thorough coverage essential).
• Acephate + fenbutatin-oxide (Ortho Systemic Insect Killer / Orthene).

Spray to full runoff, including inner canopy. Repeat per label. Predatory mites often reestablish naturally if broad-spectrum insecticides are avoided.