Storage Rots symptoms on Sweetpotato
Storage Rots (fungi - soft rot - Rhizopus stolonifer, Java black
rot - Diplodia gossypina, charcoal rot - Macrophomina phaseolina
and others): Storage rot losses are greatly reduced when
disease control practices are followed that yield high quality
sweetpotatoes from the field. Some fungi causing storage rots
infect roots in the field before harvest while others enter the
potatoes through wounds made at harvest or during handling.
Decayed spots may be dry or soft, the latter due principally to
Rhizopus rot. Sweetpotatoes should be cured for seven to 10 days
at 85oF. and at 90 percent relative humidity before being stored.
Curing allows a natural healing process to take place. Potatoes
should be stored at 55o to 60oF. and at 85 to 90 percent relative
humidity. Avoid rough handling between curing and storage
because additional wounding may occur. Store in a thoroughly
clean and disinfected room with adequate ventilation. Do not
permit the storage temperature to drop below 55oF. or injury will
occur. For control of Rhizopus rot during the
processing-to-market interval, apply a fungicide spray
immediately after washing, when potatoes are on conveyor belts or
rollers.
January, 1996
