Losses from bacterial soft rot are most prevalent in winter, when atmospheric conditions are such that potatoes remain wet or damp after washing and packaging. Experiments have shown that the disease develops rapidly when relative humidity is 90% or higher and temperature is 60 °F or warmer, and that it can be prevented by drying potatoes after washing.

James B. Kendrick, Jr., Associate Plant Pathologist, University of California, Riverside, determined the conditions for development of bacterial soft rot. Charles Sill Co., Shafter, and Summit Farms Co., Tehachapi, cooperated in testing the dryer in their packing houses.

Development of the dryer was requested and funds provided by the Research Committee of the California Long White Potato Advisory Board.

The above progress report is based on Research Project No. 947.