The occurrence of thiabendazole-resistant isolates of Polyscytalum pustulans and Helminthosporium solani on potato seed tubers in relation to fungicide treatment and storage

A - Papers appearing in refereed journals

Carnegie, S. F., Cameron, A. M., Hide, G. A. and Hall, S. M. 1994. The occurrence of thiabendazole-resistant isolates of Polyscytalum pustulans and Helminthosporium solani on potato seed tubers in relation to fungicide treatment and storage. Plant Pathology. 43 (6), pp. 961-971.

AuthorsCarnegie, S. F., Cameron, A. M., Hide, G. A. and Hall, S. M.
Abstract

Tubers infected with thiabendazole-sensitive isolates of Polyscytalum pustulans and Helminthosporium solani were treated annually for 4 years with benomyl, thiabendazole or a formulated mixture of thiabendazole and imazalil, and grown at three farms in Scotland. The proportion of thiabendazole-resistant isolates of H. solani increased, and isolates producing black colonies became more common with successive annual applications of thiabendazole or benomyl. Silver scurf was not reduced after three annual applications. When these fungicides were applied once to untreated seed the incidence of resistant isolates of H. solani was much less in 1988 than in 1991 when tubers had been grown on farms for 3 years from untreated seed. The proportion of resistant isolates of P. pustulans increased with the number of successive applications of thiabendazole or benomyl but at differing rates on each farm. At one farm, skin spot was not reduced by three annual applications of these fungicides whereas at the other farms it was reduced by 90-100% by four annual applications. A smaller proportion of resistant isolates of P. pustulans and H. solani was obtained after applying the mixture of thiabendazole and imazalil than after benomyl or thiabendazole alone. Their occurrence was not related to the number of fungicide applications. The mixture also reduced both diseases by more than 75% over the 4 years. At one farm where resistant isolates of H. solani were present, tubers were infected when stored on trays but not when stored in bags.

KeywordsAgronomy; Plant Sciences
Year of Publication1994
JournalPlant Pathology
Journal citation43 (6), pp. 961-971
Digital Object Identifier (DOI)doi:10.1111/j.1365-3059.1994.tb01645.x
Open accessPublished as non-open access
Funder project or code103
916
204
Project: 091275
Project: 091023
ISSN00320862
PublisherWiley

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