小麦纹枯病(Phizoctonia cerealis)产量损失和防治指标的研究

STUDIES ON YIELD LOSS CAUSED BY SHARP-EYE SPOT OF WHEAT (RHIZOCTONIA CEREALIS)AND ITS ACTIONTHRESHOLD

田间试验结果指出,在山东文登市,种植感病品种济南13,肥力和密度水平越高,小麦纹枯病发病越重,所致产量损失越大。根据试验数据,导出了产量损失率与小麦纹枯病扬花期,灌浆期,乳熟期病指的多元回归方程,回归均达极显著水平(α=0.01)。根据纹枯病病指增长曲线和起身期与扬花期病指的相互关系,初步推算出,在一般气侯条件下,纹枯病防治指标为拨节期病指是2%,如预报4、5月份雨量大幅度多于常年,则防治指标还要降低。

Yield loss of wheat caused by Rhizoctonia cerealis under deferent condition combinations of nitrogen urea top dress ing and rate of seeding was studied with susceptible cultivar Jinan 13 by fieldexpe- riment.Both urea top dressing and high rate of seeding beyond normal level being favourable to the disease development and aggravated the yield loss. Multiple regression models were derived with yield loss as the de- pendent variables and the disease indexes at booting,flowering and mil- ky rape stage as the independent variables. Based on the rate of disease progress from erecting stage to flowe- ring stage,the economic threshold and action threshold was tentatively studied.