Cypress mite

The cypress mite (Trisetacus macrocarpae) is a microscopic pest belonging to the Eriophyidae family. These mites are extremely small, typically measuring less than 0.3 mm in length, which makes them invisible to the naked eye.

They possess a worm-like, elongated body, usually creamy or yellowish in color. Their morphology is perfectly adapted for living in narrow spaces, such as inside buds or between the scales of coniferous foliage.

This mite primarily attacks species within the Cupressaceae family, including Cupressus, Juniperus, and Thuja. They are considered pests of economic and ornamental importance.

By feeding on the sap of young shoots and needles, they cause cellular damage that disrupts the tree's growth regulators. This leads to stunted growth, loss of foliage density, and severe weakening of the host plant.

The life cycle begins in early spring when the mites emerge from their overwintering sites within buds or under bark scales. The migration to new, succulent growth coincides with the start of the plant's vegetative period.

Development is most rapid during warm, dry summer months. Multiple overlapping generations can occur throughout the growing season, potentially leading to high population densities if conditions are favorable.

Infested plants often display abnormal growth patterns, such as distorted or bunched shoots, commonly referred to as "witches' brooms." The foliage may lose its healthy green color, turning yellowish or brown.

Affected branches often suffer from needle drop and twig dieback. If the infestation is left untreated, the cumulative damage can lead to the gradual decline and death of the entire tree or shrub.

Control is challenging because the mites are well-protected within plant tissues. Systematic acaricides are the most effective chemical intervention to reach the pests during their active stage.

• Monitor plants for symptoms in early spring.
• Prune and destroy heavily infested branches.
• Apply specific miticides during the bud-break period.
• Ensure proper irrigation to reduce plant stress.
• Encourage natural predators if possible in low-infestation areas.