Plum gall mite

The plum gall mite (Phyllocoptes hypofrons) belongs to the order Trombidiformes and the family Eriophyidae. These are microscopic, eriophyid mites that specialize in feeding on various species within the Prunus genus, causing significant physiological stress to plum trees and related stone fruits.

The life cycle of the mite is closely synchronized with the phenology of the host plant. Adult females overwinter in protected sites such as bud scales, crevices in the bark, or near the base of branches. As temperatures rise in early spring, they emerge to migrate to emerging leaves, where they establish colonies and begin feeding.

The damage is characterized by the formation of galls or abnormal tissue growths on the leaves. As the mites feed, they inject saliva that triggers the plant to develop irregular structures, including blisters, pimples, or severe leaf curling. This damage disrupts photosynthesis, ultimately reducing the tree's vigor and the quality of the fruit harvest.

Reproduction is rapid, with multiple generations developing throughout the growing season. The mites are easily dispersed by wind, allowing them to spread quickly across an entire orchard. Because of their minute size and ability to hide within galls, they are often difficult to detect until the damage has already become widespread.

Management strategies require both cultural and chemical interventions. Pruning and destroying heavily infested twigs help reduce the initial inoculum level. Chemical control involves the application of specific acaricides during critical periods, such as the pre-bloom stage or early leaf emergence, ensuring thorough coverage to reach the mites before they are protected by gall tissue.