The Comprehensive Effect Of Different Planting Date、Agricultural Chemical And Variety On Clubroot Of Oilseed Rape

In recent years, the happening and the harming of the disease in Anhui province showed a trend of rising year by year. It caused by Plasmodiophora brassicae wor. The fungal main infect the root of the rapeseed. And it will obstruct the roots to absorb water and nutrients, and then the rapeseed growth will be slow. The rape yield and quality will be greatly reduced. Due to the lack of resistant resources and hardly to prevent and treat of the disease, clubroot disease epidemic area and severity increased year by year, and has gradually grow up to be the main diseases affecting the rape yield and quality.According to the present circumstance of clubroot disease, using the design of orthogonal design, we chose three kinds of fungicides which have shown well effect on this disease, and three kinds of rape varieties which have shown different disease-resistance. In the seeding date of September 22th, September 29th and October 5th, respectively, we investigate the comprehensive effect planting date, fungicides, variety and their combination on the disease index and production. We found the following results:During the whole period of development, disease index of rapeseed grew heavilier gradually during growth, it was lowest at seeding stage, higher at enlonged period and highest at maturity period.In comparison to 50% fluazinam and 80% carbendazim, disease index of 10% cyazofamid treatment was lowest. Compared to Huiyou 50 and Wanyou 20, disease-resistant effect of Zheping 4, which was a disease-resistant variety, was better. Disease index decreased as the delay of sowing date, which was from September 22th to September 22th, then to October 5 th.The result of clubroot disease and its development was close to variety, sowing date and fungicides. Meanwhile, in seeding stage, the key factors that influenced the index of clubroot disease were sowing date and fungicides. As well as variety and sowing date in enlonged period, and variety and sowing date in maturity period.Effective pod number in single plant, seed number per-pod and 1000-seed-weight were different which depend on variety and sowing date. The final output of oilseed rape was obviously affected by sowing date, it was not influenced significantly by variety and fungicides, while effect of fungicides was heavier than variety. Moreover, final output of oilseed increased gradually as the delay of sowing date, which was from September 22th to September 22th, then to October 5 th.Sowing date was the most critical factor that affected the index of clubroot disease regardless of development period. Sowing date at October 5th showed lowest disease index, and cause the best control efficiency, which percentage was more than 50%. Especially in premetaphase of development, percentage of disease-prevention oilseed rape was more than 90%. Thus, sowing date at October 5th was beneficial for both degradation of clubroot disease and promotion of final production.Disease index in different development period held predominant role in the final production of oilseed rape. As the increasing of disease index, production would decrease.Taken together, we obtained the optimal planted projection with lowest disease index and highest output, which variety was Zheping 4, sowing date was October 5th, fungicides was 10% cyazofamid (diluted for 500 times) for atomization treatment when seeding.10% cyazofamid (diluted for 500 times) was perfused to the root of rape directly 10 days after seeding with 0.2 kg per hole.