Willow gall mite

The willow gall mite (Eriophyes salicicola) is a microscopic pest belonging to the family Eriophyidae. These mites are specialized plant parasites that induce the formation of abnormal tissue growths, known as galls, on the leaves of their host plants.

The primary hosts for this mite are trees of the genus Salix (willow). They are frequently found in ornamental gardens, nurseries, and wild plantations, where they can significantly impact the health and appearance of the trees, especially if the infestation remains unchecked for long periods.

The biological cycle of this pest is synchronized with the phenology of the willow tree. Adult females overwinter under the bark scales or inside buds. Once the leaves begin to unfold in the spring, the mites colonize the young tissue. As they feed, they induce the plant to form a gall, providing a protected environment for feeding and reproduction.

Damage caused by the mite is characterized by the presence of numerous small, often reddish or brownish galls on the leaf surface. High levels of infestation lead to severe leaf distortion, reduced photosynthetic capacity, and premature defoliation, which causes significant stress to the host plant and impairs its aesthetic value.

Effective management requires a combination of cultural and chemical strategies. Cultural practices involve pruning and destroying heavily infested branches and raking up fallen leaves to reduce the overwintering population. If damage is severe, targeted application of acaricides during the early stages of bud break can effectively limit the mite population and prevent further spread.