Epidemics Of Sclerotinia Stem Rot Of Oilseed Rape In Two Rotation Systems And Biocontrol Of The Disease Using Coniothyrium Minitans

Sclerotinia stem rot of oilseed rape is one of the most important fungal diseases in Hubei province, China. Epidemics of Sclerotinia stem rot of oilseed rape in Huanggang and Wuxue counties were investigated in this study, and efficacy of Coniothyrium minitans in different methods for controlling Sclerotinia stem rot was also evaluated.The investigation (2011-2013) demonstrated that apothecia appeared in late February or in early March,and disappeared after middle April. Peak time was in late March or early April. Apothecia in cotton-rapeseed succession fields were more than in rice-rapeseed succession fields. In the former the largest number of apothecia was15.7/m2, while in the latter only appeared in some time and some sites. Foliar diseases appeared in middle March or late March. Peak time was in middle April or late April.Diseases on leaves and stems in cotton-rapeseed succession fields were higher than in rice-rapeseed succession fields. In the former the peak foliar disease incidence was20.9-39.6%, while the latter was34.7-49.5%. Precipitation in flowering time and the number of apothecia were positively correlated foliar diseases. Stem diseases was appeared in early April or middle April (except2012).more rainy days, higher diseases. Before the harvest, in the former the stem disease incidence was2.7-26.7%, while in the latter was3.6-27.7%.The study in2011demonstrated control effect on sclerotinia germination with applications of Coniothyrium minitans was obviously. The decrement of apothecia was60%, the decrement of disease incidence and disease index were55.5%and56.9%.The study in2012demonstrated that control effect of plot experiments with applications of Coniothyrium minitans was obviously. The control effect of107conidia/ml was the same as chemical, the decrement of disease incidence and disease index were43.9～63.5%and41.8-50.3%. The decrement of disease incidence and disease index about chemical were40.2～75.6%and40.9～70.5%. At the same time, the control effect was stable. Demonstration field trials (2011-2013) in Wuxue County, the control effect of Coniothyrium minitans was obviously. In2011, the decrement of disease incidence in more than half of demonstration fields was65%, while the decrement of disease index in more than half of demonstration fields was57%; In2012, the decrement of disease incidence in more than half of demonstration fields was40%, while the decrement of disease index in more than half of demonstration fields was53.3%; In2013, the decrement of disease incidence in more than half of demonstration fields was50%, while the decrement of disease index in more than half of demonstration fields was50%.