稻粒黑粉病主要发病因素及防治指标

INCIDENCE FACTORS OF KERNEL SMUT OF RICE AND ITS CONTROLLING THRESHOLD

稻粒黑粉病已成为杂交稻制种田的重要病害,病粒率一般达10％左右。因此各地对其研究逐渐增多,但对其主要发病因素特别是防治指标报道甚少。本文通过田间试验、大田调查、室内考种并结合气象资料分析,在这方面对其进行了探讨。结果表明,杂交稻品种及其不育系、同一不育系的不同播期、不同施肥量及气候与稻粒黑粉病发病关系密切,而密度与发病关系不密切。稻粒黑粉病单穗病粒数与产量损失的关系为:Y=-2.645+1.320X(r=0.9587^(**)),防治指标为病粒率1.26％。

The results show that the relationship between rice cultivars, date of planting, fertilizing, climate and incidence of kernel smut of rice was close while the density of plants was not. The regression equation of yield loss and the number of diseased grains in a rice spike was established as Y = - 2. 645 + 1. 320X (r= 0. 9587). The control threshold was determined as the rate of diseased grains reaching 1. 26%.