Virus diseases are one of the most important production constraints facing sweetpotato producers. Yield, skin color, shape and quality of storage roots can be greatly reduced when sweetpotatoes become infected with these viruses. Yield reductions can exceed 40%, and cracks may develop in the roots making them unmarketable. Often 100% of plants in a field are infected by the end of one growing season. Planting clean, virus-tested plants can help mitigate the issues caused by sweetpotato viruses.
Testing for viruses in the lab
The first clean seed program for sweetpotato was started in the 1960s in California. At that time, it was well known in the industry that new seed stock was required to prevent Russet Crack and “variety decline,” or the gradual loss of yield that occurred in many varieties. The use of virus-tested seed is one of the reasons for substantial sweetpotato yield increases. Clean material, coupled with higher yielding, disease-resistant varieties has resulted in marked increases in yield in recent decades. In 1967, average yields in California were 5 tons/acre; in 2001 average yield had more than doubled to 12 tons/acre.
Sweetpotato leaf disease
Sweetpotato clean seed programs are established in California, Louisiana, North Carolina, and Mississippi. Other sweetpotato producing states are interested in developing clean seed programs.