Grape leaf rust mite

The grape leaf rust mite (Calepitrimerus vitis) is a member of the Eriophyidae family, known as a significant pest in viticulture worldwide. These microscopic organisms feed on the green tissues of grapevines, causing stunted growth and yield reduction.

The pest primarily targets grapevines (Vitis spp.). Its host range is limited to this plant family, but the damage inflicted can be devastating, especially in younger vineyards or susceptible grape varieties where mite populations can reach high levels quickly.

The mite's life cycle is tied to the grapevine's phenology. Fertilized females overwinter under the bark scales of the previous season's wood or in bud scales. As temperatures rise in early spring, they migrate to the developing buds and young leaves to feed and reproduce, producing several generations per year.

Symptoms of infestation include leaf malformation, curling, and the appearance of characteristic chlorotic or necrotic spots. In severe cases, internodes become shortened, shoot growth is stunted, and flowers or small berries may drop, leading to significant economic losses in the vineyard.

Effective management strategies include the following steps:

• Application of sulfur-based acaricides during the bud-burst stage.
• Usage of dormant oil sprays to target overwintering females.
• Encouragement of predatory mite populations to provide natural biocontrol.
• Pruning and removing infested shoots to reduce the overwintering reservoir.