Elimination of fusarial contamination on seed potatoes

Pieces cut from seed potatoes naturally contaminated with fusarial propagules may produce poor stands if they are planted untreated in cold soils that retard sprouting. In 1972 and 1973, contaminated tubers were given various physical and fungicidal treatments in Maine to eliminate infectious propagules, and planted in North Carolina and Maine. Freshly cut and precut pieces from each of the treatments were evaluated for control of seedpiece decay. Washing tubers improved stands slightly and tended to reduce the number of small plants but did not increase yields. Precut pieces yielded significantly less than fresh cut in Maine and significantly more in North Carolina. All fungicides increased yields at both locations. Thiabendazole and benomyl practically eliminated the inoculum. In a pilot test, pieces cut from tubers sprayed with thiabendazole and benomyl in Maine produced plants and yields in North Carolina that confirmed experimental results and showed that fungicides reduce fusarial inoculum on seed potatoes.