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Postharvest Pathology and Mycotoxins

Comparison of Thiabendazole and Genetic Resistance for Control of Sugar Beet Storage Rot. W. M. Bugbee, Plant pathologist, U. S. Department of Agriculture, Science and Education Administration, Agricultural Research, North Dakota State University, Fargo 58105; D. F. Cole, plant pathologist, U. S. Department of Agriculture, Science and Education Administration, Agricultural Research, North Dakota State University, Fargo 58105. Phytopathology 69:1230-1232. Accepted for publication 8 June 1979. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1979. DOI: 10.1094/Phyto-69-1230.

The fungicide 2-(4-thiazolyl)benzimidazole (thiabendazole) protected roots of two susceptible sugar beet cultivars from stroage rot caused by Phoma betae, Botryis cinerea, and Penicillium claviforme when roots were stored at 5 C and 100% relative humidity for 100–150 days. A similar reduction in storage rot was measured for roots of two breeding lines with resistance to those storage pathogens. Susceptible roots that were inoculated with a mixture of the three pathogens suffered 12–13% rot (fresh weight basis) in 1976 and 2% in 1977. In roots treated with thiabendazole, rot was 3–7% in 1976 and 0.02–0.1% in 1977 and inoculted roots of the resistant breeding lines suffered 3–8% rot in 1976 and 0.6–1.2% in 1977. Statistically significant losses in sucrose, clear juice purity, and recoverable white sugar per ton occurred during the 1977–1978 storage season in susceptible inoculated roots that averaged 2% rot by weight. Loss in juice quality was less in roots of commercial sugar beet cultivar American Crystal 2 hybrid B treated with thiabendazole than in those of untreated roots. There was no change in juice quality of the inoculated resistant roots. The genetic storage rot resistance in the two breeding lines used here may afford protection comparable to that provided by thiabendazole.