Abstract:

【Objective】Examine the virulence and field efficacy of several fungicides and their combinations against Cercospora beticola to guide the management of beet leaf spot disease.【Methods】The mycelial growth rate method was used to assess the virulence of 12 fungicides against Cercospora beticola. The field efficacy of various fungicides and their combinations were examined.【Results】40% flusilazole was the most virulent against Cercospora beticola with EC₅₀ value of 0.13 μg/mL. With a co-toxicity coefficient of 137.17,the combination consisting of 45% fentin acetate+37% difenoconazole 1∶1 compound had the strongest synergistic effect. The field efficacy of 45% fentin acetate+37% difenoconazole 1∶1 compound,50% pyrazole ether fungus ester+45% fentin acetate 1∶1 compound and 40% flusilazole were 78.91%,77.86% and 77.31%,respectively,with good control effect.【Conclusion】Beet leaf spot was well controlled by 45% fentin acetate+37% difenoconazole 1∶1 compound,50% pyrazole ether fungus ester+45% fentin acetate 1∶1 compound,and 40% flusilazole.

Key words: Cercospora beticola, Fungicides, Virulence analysis, Field efficacy