Potato pink eye is a disorder that causes raised pink areas on immature tubers, usually around the eyes. As the skin sets, the pink areas eventually dry and develop into brown corky patches. The symptoms do not usually extend more than a few milimeters into the tuber flesh, but in severe cases can extend deeper. Sometimes the affected areas are dry and sunken. Some potato cultivars are more prone to pink eye than others; Yukon Gold, Pike, Shepody, and Clearwater Russet are particularly susceptible to pink eye.
Pink eye is a physiological disorder associated with excessive moisture and high soil temperatures or other problems like compaction that result in anaerobic conditions around the tuber. The lack of oxygen results in cell damage, and the damaged cells are unable to produce normal periderm (skin) or suberin layers (for wound healing). Pink eye is NOT caused by a pathogen. But the anaerobic conditions that lead to pink eye are also favorable for the pathogens that cause diseases like pink rot, soft rot, and Pythium leak. So, it is not unusual for pathogens to infect damaged tissue (pink eye) and cause tuber rotting diseases that mask the original problem. The periderm and suberin layers are a barrier to tuber infection and dehydration under normal circumstances, so tubers with pink eye are notorious for developing problems with soft rot and shrinkage in storage.
Pink eye is a terrible name for this disorder. The pink coloration is usually short-lived, and it doesn't always affect the tissues just around the eyes. Moreover, the name is too easily confused with pink rot, a disease that is caused by a soil-borne fungus, Phytopthora erythroseptica. In fact, potato scientists have suggested calling it "periderm disorder syndrome" rather than pink eye. They hope people will start referring to it as "PDS" for short.
There have been several cases of pink eye (or periderm disorder syndrome) occurring in Clearwater Russet in the Columbia Basin in the last two seasons. Unfortunately, it is difficult to control disorders that depend greatly on environmental factors. There isn't much we can do about the heat. But growers can watch soil moisture levels and avoid overwatering, especialy later in the season when water needs decrease significantly. For more information, read the Irrigation Management section of Cultural Management of Clearwater Russet Potatoes by R. Spear, N. Olsen, M. Thornton, and A. Karasev.
