Hi Neil,

The damage on the plant suggests pear leaf blister mites . These mites feed inside leaf tissue resulting in green to reddish blistered areas on the leaves. As the leaf tissue dies, these blisters will ultimately turn brown to black. Once blisters develop, the damage has been done and any action will need to be done in the fall or spring.

Here are two links for more information:

https://extension.usu.edu/planthealth/ipm/notes_ag/fruit-blister-mites

https://pnwhandbooks.org/insect/tree-fruit/pear/pear-eriophyid-mite

You can always drop off a leaf and I can take a look; you really need a microscope to see these tiny mites inside the blisters.

Please reach out if you have any further questions!

Lisa

Lisa Cowan

Outreach Program Coordinator – Community Horticulture Program

Oregon State University

OSU Extension Service – Deschutes, Crook, Jefferson Counties

3800 SW Airport Way, Bldg #4

Redmond, OR 97756

Tel.:<personal data hidden> (direct line) I<personal data hidden> (x79590 - main line)

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