Sensitivity to silthiofam, tebuconazole and difenoconazole of Gaeumannomyces graminis var. tritici isolates from China.

Yingzi Yun, Fangwei Yu, Ning Wang, Huaigu Chen, Yanni Yin, Zhonghua Ma

Index: Pest Manag. Sci. 68(8) , 1156-63, (2012)

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Abstract

Wheat take-all caused by Gaeumannomyces graminis var. tritici (Ggt) has become an emerging threat to wheat production in the last few years. Silthiofam is very effective against Ggt, and recently it has been widely used for the control of take-all in China. However, farmers have noted a decline in control efficacy with this compound in some wheat fields, suggesting that the pathogen may have developed resistance to silthiofam.Of the 66 Ggt isolates collected from different locations in China, 27 were resistant to silthiofam. There was no cross-resistance between silthiofam and tecuconazole or difenoconazole. The effectiveness of silthiofam in controlling take-all was compromised on wheat inoculated with silthiofam-resistant isolates. Based on the DNA fingerprinting generated by microsatellite PCR, two predominant genetic clusters were found among these isolates and were clearly associated with the sensitivity to silthiofam.Silthiofam has a high risk in the development of resistance in Ggt. Tebuconazole and difenoconazole show great potential for control of take-all on wheat. Results from this study provide useful information for take-all control and the management of fungicide resistance.Copyright © 2012 Society of Chemical Industry.