井岗霉素对稻纹枯病控病效果的定量研究

Quantitative Study on the Controlling Effect of Jinggangmeisu on Rice Sheath Blight

在连作早稻上喷施井岗霉素防治纹枯病(Rhizoctonia solani),其控病效果与施药时病情基数(x)、控病时间(T)有关。早稻纹枯病的施药次数以一至二次为宜,施药适期为孕穗(剑叶展开)至灌浆期,一次施药的适期为孕穗至抽穗期,控病效果为0.63—0.74;两次施药(间隔10天)的适期为孕穗至灌浆期,控病效果为0.86—0.93。

Quantitative study on the effect of Jinggangmeisu on sheath blight of early season rice showed that the controlling effect by spraying with normal dosage was related to the disease index(x) and disease contrlling time (T). The mathemetical expression is: P=(0.5+0.8924/(1+0.9091exp(14.0848x)))*(0.3+0.71/(1+0.00654exp(0.1705T))) The appropriate period for spraying was from booting stage (extending of flag leaf) to kernel stage. The proper period for one time spraying was within booting and heading stages, and the controlling effect was 0.63 to 0.74. The apt spraying period for twice should be from booting to kernel watery stage, interval with 10 days was best. Controlling effect was from 0.86 to 0.93. Spraying more than twice seemed to be unnecessary.