Name: Eriophyes pyri
Alias: The pear leaf blister mite, or pear rust mite. This is such a small pest that it is almost pointless to describe the physical characteristics. It is a small (too small to see with the naked eye) mite that feed and live in the leaves, which causes blisters on fruit tree leaves in early spring. Once the petals fall off of the blooming plant, the mites have already laid their eggs for the year inside of the blisters they have created. They feed on developing buds throughout the winter.
Crimes: The blisters created by the mites is their room and board. Low infestations can be tolerated, although the yellow and brown blisters can be unsightly. Under heavy imfestations they can cause damage to the developing buds of the fruit tree and stunt growth for the year.
Redeeming qualities: None known.
Sentence: Once blistering patterns are noticed, it is too late to apply any form of treatment. Pear leaf blister mites can be suppressed with an application of a dormant oil in the late winter or early spring before the mites have emerged. Many chemicals are labeled to be applied in the spring including carbaryl, or pyrethroid based insecticides. Always read and follow the label instructions.