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基于对1999—2008年陕西省气温、相对湿度以及陕西省苹果主产区苹果褐斑病发生、流行的监测,对苹果褐斑病发生时间、发病规律及流行程度进行了分析,并构建了旬平均气温(T)和旬平均相对湿度(Hm)影响下苹果褐斑病一维和三维动态预测模型.结果表明:研究区苹果褐斑病受环境因素影响严重,7、8月在田间扩展迅速并引起大量落叶,危害可持续至9月,初霜后不再有新病斑扩展;构建模型所用的T和Hm与田间实际条件基本一致,苹果褐斑病三维动态预测模型为:f(T,Hm)=-0.0172T3+0.9497T2-16.2209T+88.9923-0.00001Hm3+0.00354Hm2-0.15554Hm+2.36578[f(T,Hm)为病情指数].模型结果表明,田间引起苹果褐斑病发生的T为15℃,大流行条件为7、8月T为23℃、Hm在90%以上.
Based on the temperature and relative humidity in Shaanxi Province from 1999 to 2008 and the occurrence and prevalence of apple leaf spot in the main apple producing area in Shaanxi Province, the occurrence time, incidence and prevalence of apple leaf spot were analyzed and constructed The average temperature (T) and the average relative humidity (Hm), the results showed that the apple brown spot in the study area was severely affected by environmental factors and rapidly expanded in the field in July and August Causing a large number of deciduous leaves, the damage sustainable until September, after the initial frost no longer new lesions expansion; building models used T and Hm and field actual conditions are basically the same, apple brown spot three-dimensional dynamic prediction model: f (T, Hm) = - 0.0172T3 + 0.9497T2-16.2209T + 88.9923-0.00001Hm3 + 0.00354Hm2-0.15554Hm + 2.36578 [f (T, Hm) is the disease index.] The model results show that in the field, the occurrence of brown leaf spot in apple Is 15 ℃, the pandemic condition is 7, August T is 23 ℃, Hm is above 90%.