Russeting and Russet Scab of Prune, an Environmentally Induced Fruit Disorder: Symptomatology, Induction, and Control

Abstract

Typical symptoms of russeting of immature fruit of French prune (Prunus domestica) originate as shiny, lacy areas on the stylar end of fruit and become brown and scabby (russet scab) on ripe fruit. These areas have a thin (1.9-3.8 μm) cuticle, lack epicuticularwax, and bear abnormal stomata. In contrast, healthy areas have a thick (8-12 μm) cuticle, abundant epicuticular wax, and normal stomata. Russeting and russet scab have been most severe when rainfall has occurred during and 1 wk after full-bloom stage