Abstract:

【Objective】 Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum is a damaging disease of oilseed rape. The sensitivity of S. sclerotiorum to prochloraz-manganese chloride (PMC) and the other three fungicides, carbendazim, dimetachlone-mancozeb and carbendazim-triadimefon was tested. The aim of this study was to assess the potential of PMC in controlling SSR and to screen novel fungicides against Sclerotinia disease. 【Method】 The effects of fungicides on S. sclerotiorum hyphal growth and sclerotial germination, and their protective and therapeutic effects were determined in laboratory. Potential of fungicides in controlling SSR was tested in field. 【Result】 The pathogen was highly sensitive to PMC with the median effective concentration (EC50) to S. sclerotiorum hyphal growth at 0.02 mg?L-1, but less sensitive to carbendazim, carbendazim-triadimefon and dimetachlone-mancozeb. The results showed that myceliogenic germination of S. sclerotiorum sclerotia was delayed by 20 mg?L-1 PMC, and carpogenic germination was inhibited by PMC at 0.5 g?L-1 with the inhibition percentage at 82.9%. PMC had both protective and therapeutic effects on Sclerotinia disease. Field efficacy of PMC on S. sclerotiorum was as high as 88.1%. 【Conclusion】Prochloraz-manganese chloride is a promising fungicide in controlling Sclerotinia disease of oilseed rape.

Key words: Sclerotinia disease, fungicide, prochloraz-manganese chloride, Sclerotinia sclerotiorum