Changes in sensitivity to DMI fungicides in Rhynchosporium secalis

摘要: Abstract Laboratory tests on 2000 isolates of Rhynchosporium secalis from throughout the UK over a 4-year period revealed decline in sensitivity to triadimenol and propiconazole but not prochloraz. Change occurred irrespective disease pressure, was correlated with fungicide use. Resistant were no less pathogenic than sensitive ones. Selection generated bimodal population distribution, whereas produced gradual shift unimodal towards mean. Some cross-resistance between triadimenol, third triazole, tebuconazole, although change tebuconazole always other two triazoles. No observed imidazole demethylation inhibitor (DMI), Field-trial data collected several years showed that performance lesser extent, propiconazole, had declined. Control these fungicides could be improved by using mixtures carbendazim. Tebuconazole, either alone or carbendazim tridemorph, provided best control, did appear select for lower sensitivity. The findings emphasize certain DMI may still used strategies where DMIs has been altered because resistance.