I have yet to meet a potato grower who is not familiar with the symptoms of the Fusarium dry rot that develops in storage. The skin of infected areas is wrinkled, and there is a dry, non-smelly rot in the affected flesh. However, Fusarium may also infect potato seed during transit or handling. Bruises or wounds allow Fusarium and also soft rot bacteria to get into tubers.
I received a photo last week of infected seed potatoes. One of the tubers shows the wet phase of Fusarium, a phase that occurs briefly as the fungus infects new tissue. There is also a rotten tuber that looks infected with both Fusarium and soft rot.
Tubers with the wet phase of Fusarium are not smelly; those infected with soft rot smell foul. Registered seed treatments usually include a fungicide to protect healthy tubers from Fusarium, but fungicides do not protect against soft rot or the blackleg form of soft rot.
This photo shows the wet phase of Fusarium which I found while a grower was cutting seed.
