Potatoes

Pink rot is a tuber decay that occurs sporadically, usually near the end of the season. It affects roots, stolons and tubers. Infected areas of the tuber surface turn purplish-black. The margin of the decay may be delineated by a dark line. Infected skin is easily rubbed off.

Initially, the affected internal tissue is cream-to-light brown and has a rubbery consistency. When exposed to the air, the rot turns salmon-pink, progressing to grey and then black. Occasionally, wilting of plants may occur as a result of pink rot infection 

The pink rot fungus survives as thick-walled spores in the soil for many years. Tuber infection usually occurs before or at harvest. The disease is associated with excessive soil moisture, low spots in the field, over-irrigated areas and poorly drained soils. The fungus penetrates the tubers mainly through the stolons. However, infection through lenticels and eyes can occur. Tubers may also be infected through wounds made during harvest and handling.The varieties Superior, Russet Norkotah, Goldrush, Snowden and Kennebec are very susceptible to pink rot

Pink rot develops late in the season. Dig tubers at random after top killing to assess disease incidence prior to harvest.