Volume 17 Part 1 Article 39: Emergence of Benzimidazole-Resistant Green Mould, Trichoderma aggressivum, on Cultivated Agaricus bisporus in North America

Volume 17 Part 1 Article 39
Year 2008
Title: Emergence of Benzimidazole-Resistant Green Mould, Trichoderma aggressivum, on Cultivated Agaricus bisporus in North America
Authors: C.P. Romaine, D.J. Royse and C. Schlagnhaufer

Abstract:

Benzimidazole fungicides have been used in the USA since 1996 for the prophylactic treatment of the spawn and, more recently, the time-released supplement in the control of green mould incited by Trichoderma aggressivum f. aggressivum (Ta2) on cultivated Agaricus bisporus. Between 1994 and 2002, we observed an approximately three-fold increase in benomyl resistance within the Ta2 pathogen population associated with the major mushroom-growing region located in Pennsylvania. The findings of a survey conducted during 2005 revealed that the pathogen had developed marked resistance (>100-fold increase) to both benomyl and thiophanate-methyl. In a cropping trial, the use of the maximum allowable rate of thiophanate-methyl effectively controlled green mould disease caused by a benzimidazole-sensitive isolate, but not a resistant isolate. Imazalil sulfate, an imidazole, was found to be effective as a spawn and supplement treatment for benzimidazole-resistant Ta2.

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