Quantitative Study on the Controlling Effect of Jinggangmeisu on Rice Sheath Blight
Ding Kejiang Ji Boheng Tan Genjia (Department of Plant Protection, Anhui Agricultural College) Zhou Yuhe Ji Mingfu (Anqin Institute of Agricultural Science)
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.