Pear rust mite

Infestations of E. pyri originate from overwintering females, which begin to feed and oviposit on expanding fruit- and leaf-buds in early spring. Mites can be found on the calyx of flowers before petal fall and will feed on fruit as soon as it begins to form. Pear is relatively intolerant of mite feeding and damage symptoms can appear early in the season.

The first symptoms of cumulative feeding are typically seen on the ventral surface of leaves and around the calyx of fruit. On leaves, cumulative feeding causes browning of the lower surface, and cumulative feeding damage on fruit is manifest as a browning of the surface, known as russet.