Pearleaf blister mite
Phytoptus pyri
12 host plants
Last updated
You will see reddish to yellowish-green blisters erupting from pear leaves in spring as buds swell and leaves unfurl. Blisters turn brown or black by late season as tissue dies. Heavily infested leaves drop prematurely, weakening trees. These microscopic mites overwinter under outer bud scales and begin feeding immediately as buds burst. Three host plants including pear are affected.
Plan management for the following season after observing current year damage. Dormant sprays in late fall and winter target overwintering mites beneath bud scales if prior damage was severe. Avoid broad-spectrum insecticides that kill phytoseiid predator mites that naturally control blister mites. Heavy rain and cold weather suppress populations. Most trees tolerate mild blister mite injury.
Quick Reference
Pearleaf blister mites are tiny, white to yellowish eriophyid mites that feed on leaves and fruit. Damage on leaves is caused by mites feeding inside the leaf tissues, resulting in the formation of pale green to reddish blistered areas on the leaf. Later in the summer these blistered areas will turn brown to black as the leaf tissue dies. Leaf blisters are typically 1⁄8" to 1⁄4" in diameter. Severe blister mite infestations can cause leaves to drop. Blister mite damage to fruit consists of russetted, somewhat sunken areas on the skin. These mites overwinter under bud scales, attacking emerging
Cultural Controls
- Predatory mites help control populations by feeding on exposed mites.
- They cannot attack mites inside blisters.
- Avoid use of broad-spectrum insecticides which kill predatory mites and beneficial insects.
- Removing and destroying infested leaves may help control mite populations on small trees.
- Provide proper culture.
- Healthy trees easily tolerate some insect damage and leaf loss.