MSU Extension Integrated Pest Management

Green fruit rot

Disease

Green fruit rot

Botrytis cinerea Pers.:Fr. Sclerotinia sclerotiorum (Lib.) de Bary

Distribution: Common to all fruit-growing regions in eastern North America; most common in wet seasons.

---

Both fungi attack the blossoms but rarely invade the twig (A). Blighting of the blossoms followed by gray spore masses is typical of infection from B. cinerea. S. sclerotiorum infects senescing floral parts; the white mycelium of the fungus is sometimes observed on blighted blossoms. Fruit infection occurs when developing fruit are in direct contact with blighted blossoms. Botrytis-infected fruit develop a typical gray sporulation (B). Sclerotinia-infected fruit develop a dense white fungal growth that often leaves the fruit deformed (C).

• Crops Affected: cherries, plums

  Management

  The disease is sporadic and rarely causes major losses no practical control recommendations exist.

  Similar Species

  Blossom blight can be confused with brown rot infections. Microscopic examination of the spores may be necessary to differentiate the two.