【目的】柑橘轮斑病(citrus target spot)作为一种新发柑橘病害,造成发病果园严重的经济损失。本研究针对该病害进行适生区预测及风险分析,以便对该病采取及时、有效的管控措施,最终达到降低其流行风险等级,防止病害传播扩展的目的。【方法】基于环境变量数据和柑橘轮斑病发生分布数据,运用MaxEnt生态位模型模拟预测柑橘轮斑病菌(Pseudofabraea citricarpa)在中国的潜在适生区分布。并通过ROC(receiver operating characteristic)曲线下面积(area under the curve,AUC)评估预测模型的精度,运用正规化训练增益刀切法(regularized training gain)获取气候因子与分布概率间的关系。同时采用有害生物风险分析理论,以有害生物风险分析的规定程序为依据探索柑橘轮斑病病害的风险分析体系和评价值的计算方法,对评价指标进行定性分析,进而量化评价值。在建立综合评价模型的基础上,计算柑橘轮斑病风险性危害值,最后对病害的风险性危害值进行评价。【结果】柑橘轮斑病菌MaxEnt模型预测结果的平均AUC值为0.998,表明预测结果精度高。柑橘轮斑病菌的潜在适生区面积约占全国面积12.19%,高适生区、中适生区、低适生区各占全国面积约2.85%、3.99%、5.35%。高、中适生区主要集中于长江中上游柑橘优势区及其周边。其中,高适生区主要集中在四川、重庆、陕西南部,以及贵州、湖北等少量地区。中、低适生区是高适生区的外围扩展。通过MaxEnt模型正规化训练增益刀切法获取的环境变量重要性分析结果表明,最冷季度平均温度(Bio11)、最干季度平均温度(Bio9)、最冷月最低温(Bio6)是影响柑橘轮斑病菌分布的3个关键环境因子,这意味着低温、干冷季节柑橘轮斑病发生可能性大。风险分析最终创建出5个准则层、13个指标层的多指标综合评价体系,并对各指标层定量与定性分析,柑橘轮斑病在我�
The study was conducted to reduce blast damage, the use of pesticides residue, environment pollution and control costs, and to make a significant contribution to the improvement of grain production, quality and agriculture ecological environment. Over these years, by the methods of systematical monitoring, regular surveys, field investigation, rice blast resistance identification, experiments and meteorological data analysis, the study on comprehensive prevention and control of rice blast in Nanchong City was conducted. The results showed that the rice varieties more sensitive to blast had a higher incidence of severe blast disease. Replacing,varieties with different source of resistance every three to five years and reasonable variety distribution can effectively reduce the prevalence of rice blast. Appropriate treatment of infected rice straw and pathogen, seed disinfection, seedling disinfection, and pesticide application at transplanting and etc. can delay blast occurrence and reduce the damage caused by blast. By analyzing the blast control efficiency of pesticides applied at different growth stages, we found that best control efficiency against blast was achieved by spraying pesticide twice during the whole growth stage, once 3 d before transplanting or 10 d after transplanting; and once at initial heading stage. Spraying 525 g/hm^2 75% tricyclazole was proven to be the best dosage for blast control. However, 375-450 g/hm^2 75% tricyclazole is enough if the blast incidence is not severe, or the rice varieties are slightly susceptible to blast.The control efficiency against leaf blast between 4% kasugamycin and 20% tricyclazole had no significant difference, but was significantly higher than that of 100 billion spores/g of Bacillus subtilis. The control efficiency against neck blast had no significant difference among 4% kasugamycin, 20% tricyclazole and 100 billion spores/g of B. subtilis. 450 g/hm^2 75% tricyclazole had better control efficiency against neck blast than 2 250 g/hm^2 2% 800 million spores/g
