华北地区苗圃毛白杨叶锈病流行预测式的推导

THE DERIVING ON THE PREDICTIVE EQUATION OF EPIDEMIC OF POPLAR LEAF RUST DISEASE CAUSED BY MELAMPSORA MAGNUSIANA IN NURSERYS OF HUABEI REGION

根据1983—1987年在北京、河北、山东、山西调查的苗圃毛白杨叶锈病病情,结合相应的气象数据,通过逐步回归在18个自变量因子中,筛选出早春百株病芽数(X_1)和发病适温期间降雨量(X_2)的互作因子(X_1X_3),建立预测当年最高病情(Y)的方程式:Y=2.8229+0.0133X_1X_3。该方程经数学检验合理,两年当中建立模型以外的10例实测病情对方程式进行检验,证明有较高的可靠程度,可在华北地区试用,为防治决策提供依据。

During 1983—1987,the data of poplar leaf rust disease caused by Melamp-sora magnusiana and meteorological items of corresponding were taken from many nurserys in Huabei region.Through stepwise regression calculation,18 related factors were designed for selection.As a result,the factor-interaction between the number(X_1)of diseased poplar buds in early spring and the total quantity(X_3) of rainfall was selected.The regression equation for prediction of the disease(Y)is as follows: Y=2.4229+0.0133X_1X_3 The regression equation was obtained in X^2-test.The model was also exa- mined using both actual disease indexes and relative meteorological factors which were outside the model for many times.A better fittingness was observed between the actual and theoretical values.The model could be use in predection of poplar leaf rust disease in nur-sery and would b(?) benefitial to make decision in the disease management such as fungicide application.