Factors affecting appearance of stink bug (Hemiptera: Pentatomidae) injury on apple

Three main types of stink bug injury have been reported on the surface of apple fruit: (1) discolored dots, (2) discolored dots with depressions, and (3) discolored dots with discolored depressions. From 2005 to 2008, studies were performed to determine the factors linked to the variations in the appearance of adult stink bug injury on apple fruit observed at harvest. The main factors tested were type of feeding injury (i.e., mechanical versus breakdown and removal of tissues), time between injury and evaluation, cultivar, fruit maturity, and relative exposure to sunlight and UV radiation. No differences were observed that were caused by type of feeding. Studies of the time between injury and evaluation showed that there is a progression in the development of injury appearance. This progression of injury is influenced by cultivar and relative maturity of the fruit. Concomitantly, sites of injury on fruit exposed to no or limited sunlight and UV radiation were less likely to progress to discolored depressions.