Eriophyes piri

Pear leaf blister mite

Description

Deformations of pear leaves (pear leaf blisters) are caused by the pear leaf blister mite (Eriophyes piri). Early in spring, shortly after pear buds open, light spots can be seen on the upper surface of the leaves, and thickened areas on the lower surface. These spots later turn black during the summer. Often, all leaves on the tree are affected. More severely affected leaves do not fall off but remain on the trees until autumn. When multiple leaves are affected, the growth of the shoots is often slowed down. This species does not attack fruits. However, severe infestations can indirectly affect fruit quality and yield by impacting the overall health and vigor of the tree. Lower branches of older trees are usually the most affected. The pest is a yellowish-white mite, about 0.2 mm long, which is not visible to the naked eye. It mainly occurs on older pear trees, but occasionally it is found on young trees in fruit nurseries. The pear leaf blister mite overwinters in buds or in bark crevices. Chemical treatment of affected pear trees is usually not necessary. Typically, removing affected leaves from the trees is sufficient. In cases of severe infestation, it is necessary to treat the trees with an appropriate miticide.