Characterisation of benzimidazole‐resistant strains of Rhynchosporium secalis

Abstract

Benzimidazole‐resistant mutants of Rhynchosporium secalis were easily generated in the laboratory using UV mutagenesis. Three levels of resistance were identified (low, LR; moderate, MR; high, HR), but there was no negative cross‐resistance with N‐phenylcarbamate fungicides. In all cases pathogenicity was reduced, in some cases drastically. Benzimidazole‐resistant field strains were first detected in 1990, some 15 years after this fungicide group was first used in UK barley crops. Unlike laboratory mutants, only HR phenotypes were isolated from the field, and all showed negative cross‐resistance to N‐phenylcarbamates. These field resistant strains were no less pathogenic than wild‐type ones. Carbendazim binding to tubulin‐like protein from HR phenotypes, whether generated in the laboratory or isolated from the field, was reduced.

Control of foliar diseases in barley: towards an integrated approach

“…During the 1970s and 80s, R. commune was controlled by the use of two groups of fungicides, the MBCs and the DMIs. Both of these fungicide groups were used successfully to control R. commune, either alone or in mixtures, up until the early 1990s, after which MBC fungicide resistance was first detected (Kendall et al 1994). The frequency of MBC resistant isolates increased rapidly, especially in Northern Ireland, where in 1991-1995, approximately 50% of the pathogen population was resistant.…”

Industry Views of Monitoring and Mitigation of Herbicide Resistance

“…Oculimacula spp., cause of cereal eyespot disease (Locke, 1986) or even 15 years (e.g. Rhynchosporium secalis, cause of barley leaf-scald (Kendall et al, 1993). Over the years the use of mixtures or alternations with non-benzimidazole fungicides has been encouraged with varying degrees of vigour by the individual companies concerned and by advisory services.…”

Cotton in Brazil: Importance and Chemical Control of Bolls Rot

“…The latter ( Figure 3) specifically affects cell division, as it has selective activity for tubulin fungi, and binds to the protein, preventing the occurrence of polymerization of microtubules forming the mitotic spindle (Kendall et al, 1994;Wheeler et al, 1995).…”