Resistance phenylpyrroles

In Botrytis, dicarboximide and phenylpyrrole resistant laboratory strains [12,18] and less sensitive field isolates [13, 19] are usually found to be mutated in Dafl, the histidine kinase homologous to Os-1. However, field isolates less sensitive to dicarboximide fungicides were reported to retain wild-type levels of sensitivity to phenylpyrroles [18-20]. Vignutelli et al. [21] crossed a field resistant strain of Botrytis with a sensitive one and found that dicarboximide resistance segregated separately from phenylpyrrole resistance, suggesting different genes regulate... 

The ultimate cause of fungal toxicity upon treatment with dicarboximides, phenylpyrroles and perhaps aromatic hydrocarbon fijngicides such as chloroneb, may be an overproduction of osmoregulating polyols. Laboratory mutants defective in the os-1 gene, which encodes an early osmosensing kinase, are resistant to all three classes of fungi-... 

The inherent risk for development of resistance towards phenylpyrroles is considered as medium [39]. No cross-resistance has been reported between phenylpyrroles and products of other chemical classes, including benzimidazoles, dicarboximides, N-phenylcarbamates and anilinopyrimidines for B. cinerea [40]. 

Recently, multiple resistance of Mtemaria brassicola isolates [41] towards phenyl-pyrroles and dicarboximides was observed however, the underlying mechanisms need further clarification. Although reduced sensitivity of B. cinerea lab mutants [42] and field isolates [43] to phenylpyrroles have been observed in a very few cases, no losses in the performance of the solo or the mixture product were observed under practical commercial conditions. 

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