棉花黄萎病田间为害损失研究

Studies on yield loss cause with cotton verticillium wilt in field

在长江中游棉区，黄萎病影响产量的关键时期是在病株盛病期，病株损失率达３３５％，始病期出现的病株损失率为２３７％，而隐症后出现的病株损失率仅０９５％。黄萎病田间群体病指与棉花产量的回归方程为＾ｙ＝２６４９－１１５５ｘ±２３３４。重病田的产量损失率为１８５４％～２１４５％，轻病田为５４５％～５４７％，病指在１０以下的产量损失在５％以下。

The key period of cotton verticillium wilt (Verticillium dahliae Kleb) affecting cotton yield was thetop diseasing stage before diseased plants in the cotton growth areas of the middle reaches of Yangtze River. The yield losses of diseased plants in the key period, the disease starting period and after diseased plants became latent were 33 5%, 23 7% and 0 95%, respectively. Between the index of the disease (in the field) and cotton yield, the regression model was =2649-11 55x±233 4 (where y indicated cotton yield estimated, x indicated the index of the disease in the field). The yield losses in heavy diseased field were 18 54%～21 45%, light diseased field were 5 45%～5 47% and field with below 10 index were below 5%. Cotton population had some compensation effect on cotton yield loss caused by verticillium wilt in highly and moderately fertilized fields.