Rust Mites

Hosts

Apple, pear

Biology

Rust mites are microscopic mites in the eriophyid group.  Adults overwinter under leaf bud scales of pear and apple, and emerge with new leaf growth in the spring. 

Symptoms/Damage

Russeted fruit; pear leaves are sensitive to rust mites, becoming bronzed or scorched. 

Monitoring

Use a hand lens to inspect leaves starting in mid-spring.

Treatment Threshold

No threshold determined.

Degree Day Model

None

Management Considerations

In apple, rust mites can be beneficial in that they may serve as alternative prey for predatory mites that also help suppress spider mites.  In pear, lower populations can be tolerated as pear leaves are sensitive to injury.