Mycosphaerella leaf spot
Mycosphaerella pyri (Auersw.) Boerema
Lesions are primarily circular, 3–5 mm in diameter, and have a grayish white interior, with a distinct purple margin; small, black pycnidia develop in the interior of older lesions (A). The fungus occasionally attacks the fruit, producing small, dark lesions.
Widespread, although of minor economic importance in sprayed commercial orchards.
The disease can be confused with Fabraea leaf spot; Fabraea lesions tend to be darker.
Fungicide programs targeting Fabraea leaf spot will effectively control Mycosphaerella leaf spot.
The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.