Characterizing resistance risk of Erysiphe graminis f.sp. tritici to strobilurins

Industry Views of Monitoring and Mitigation of Herbicide Resistance

“…Within two years after their introduction, marked loss of action against powdery mildew, associated with development of highly resistant populations was observed in wheat crops in Germany, and soon after throughout north-west Europe (Chin et al, 2001 According to recent FRAC reports, in seventeen pathogens a high level of resistance (resistance factor usually greater than 100) has been shown to be caused by a single mutation (G143A) in the cytochrome bc-1 gene. Another single mutation (F129L), generally causing a much lower degree of resistance, and little or no loss of control provided recommended application rates are adhered to, has been detected in three pathogens.…”

The QoI Fungicides, the Rise and Fall of a Successful Class of Agricultural Fungicides

“…Fitness penalties have been observed in QoIresistant field isolates of P. grisea and P. viticola, and laboratory mutants of Cercospora beticola (Avila-Adame & Köller, 2003;Malandrakis et al, 2006). In contrast, fitness penalties are not apparent in QoI-resistant field isolates of B. graminis and B. cinerea, and laboratory mutants of Penicillium digitatum (Heaney et al, 2000;Chin et al, 2001;Banno et al, 2009;Zhang et al, 2009 several fungal plant pathogens and to study the impact of the introduction of the G143A substitution on bc 1 complex activity. As expected, the G143A substitution resulted in high levels of resistance to QoI fungicides.…”

Sustainable agriculture and plant diseases: an epidemiological perspective

“…Broad spectrum fungicides remained effective for long periods, but for those with single-site action the durability is often short. Following the introduction of strobilurins in 1996 to control a range of cereal pathogens, high frequencies of resistance in Blumeria graminis had been detected within 4 years over large areas of Germany, France and the UK (Chin et al 2001). Clearly, the durability of control depends upon the selection pressure imposed upon the pathogen population and the fitness of virulent or fungicide-resistant strains relative to resident, avirulent and fungicide-sensitive strains.…”

“…Complete exclusion of the resident (controllable) pathogen strain by the invading strain means that the gene or fungicide cannot be used again as a sole method of control. Empirical evidence shows both scenarios with coexistence (Chin et al 2001;Bierman et al 2002) and competitive exclusion (Baroffio et al 2003). To develop effective resistance management strategies, it is imperative to understand the processes that influence which of these outcomes is likely to occur.…”

“…Since most plants are self-evidently resistant to most pathogens, it seems perfectly reasonable to assume that advancing knowledge of the molecular and cellular bases of hostpathogen interaction will identify the means not only to engineer or to select durable resistance but also to produce effective and environmentally neutral forms of chemical control. Yet failures still occur, whether from the release of novel resistance genes (Brown & Hovmøller 2002) or from new pesticides and fungicides (Chin et al 2001). Agriculture continues to be confronted with new and recurrent epidemics.…”