水稻三种主要害虫复合为害损失的研究

Studies on the multiple species injury loss of three major rice insect pests

三化螟、稻纵卷叶螟和稻飞虱类是南方水稻的主要害虫，常在水稻生长中后期同时造成为害。网室接虫试验表明：水稻产量损失率与三种害虫的密度呈线性关系，回归方程式为：y＝0．0870＋032431x1＋0．5075x2＋0．1583x3。文中对多种病虫复合为害损失预测模型的一般形式及复合防治指标的应用进行了讨论。

Paddy stem borer Tryporyza incertulas (Waiker), rice leaf roller Cnaphlocrocis medina-lis (Guenee) and rice plant hopper (consisting of Sogatella furcifera (Horvath) and Nilaparrata luge- ns (Stal) are the major rice insect pests in the South China. They usually damage rice crop in its late development periods. Experiment in net bouse indicated that rice yield loss rate linearly related to densities of three pests. Regression equation was y = 0.0870+0.3243x1+0.5075x2+0.1583x3. Also in this paper, we discussed the general form of multiple species iniury loss forecasting model caused by multiple diseases or pests and tbe applicttion of multiple species economic thresholds.