Raspberry leaf mite

The raspberry leaf mite (Latin Phyllocoptes gracilis) belongs to the class Arachnida, order Trombidiformes, and the family Eriophyidae. By its nature, this object is a microscopic pest that causes specific plant tissue deformations, which are often mistaken for viral diseases or fungal infections.

This pest primarily infests raspberries and can also be found on certain species of blackberries. The primary damage manifests as leaf discoloration in the early stages, where leaves turn yellowish and develop small spots or chlorotic areas. As the infestation progresses, the leaf blade begins to curl and deform.

The biology of the pest is characterized by its minute size (about 0.15–0.2 mm), making it nearly impossible to detect with the naked eye. Adult female mites overwinter under bud scales and in the leaf axils of raspberry plants. At the start of the growing season, the mites move to young leaves, where they feed on plant sap, disrupting physiological processes within the tissues.

Conditions for population development depend directly on temperature and humidity levels. Mass reproduction of the mite occurs during hot and dry summer periods, when the life cycle of a single generation is reduced to just a few days. Rapid spread across a plantation is often triggered by the use of infested planting material, as well as the dispersal of mites by wind or insects.

The economic harm caused by Phyllocoptes gracilis includes stunted plant growth, significant yield reduction, and poor berry quality. In heavily infested plantations, premature leaf drop is observed, which weakens the plant before winter. Control measures include:

• Using only healthy, virus-free planting material.
• Timely sanitary pruning and removal of infested shoots.
• Application of specialized acaricides during the peak period of mite activity.
• Adhering to agricultural practices designed to boost plant immunity.