Identifying and Treating Spider Mites on Italian Cypress

An Italian cypress showing browning from the bottom up, with tiny red specks visible on a shaken branch over white paper, signals a classic spider mite infestation. These microscopic arachnids—not insects—feed by piercing needles and sucking sap, causing stippling, bronzing, and eventual needle drop, typically starting on lower, interior branches.

Spruce Spider Mite Biology

Oligonychus ununguis thrives in cool weather, peaking in spring and fall. Unlike many spider mites that explode in summer heat, spruce spider mites decline during hot months when natural predators are active. Heavy infestations produce fine webbing and can kill an arborvitae or cypress over several seasons.

Monitoring and Thresholds

Tap a branch over white paper. If dozens of mites appear per tap, treatment is warranted. Repeat checks every 7–10 days to track population trends.

Control Options

• Insecticidal soaps: Effective on contact, require thorough coverage, especially leaf undersides.
• Horticultural oils: Smother mites and eggs; apply during dormant season or cool weather to avoid phytotoxicity.
• Systemic acaricides: Products containing acephate + fenbutin oxide (e.g., Ortho Systemic Insect Killer) provide longer residual control.

Always follow label directions. Avoid broad-spectrum insecticides that kill beneficial predators like predatory mites and lady beetles, which naturally regulate spider mite populations.

Italian Cypress trees with characteristic lower-crown browning from spider mite feeding.