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一、病害的发生消长两年来的观察表明,当温度在28℃左右,湿度在90％以上,即能引起发病,在各季,各类田都是从零星见病到发病盛期,再出现发病高峰期,然后趋于稳定,停止发病。在同一块田里,病情的发展似乎可分为普遍期和上升期。所谓普遍期,是从零星发病到蔓延成片,横向发展,即病株率增加。所谓上升期,是病斑从植株下部茎叶逐步向上蔓延,上升到中部茎叶甚至顶叶和穗部,即严重度上升。当然,这两者之间并无明显界限,在严重度上升时,病株率仍在增加。
First, the occurrence of disease growth and decline Over the past two years the observation shows that when the temperature is about 28 ℃, humidity above 90%, which can cause disease in all quarters, all kinds of fields are from the sporadic see the disease to the peak incidence of re-emergence Peak incidence, and then stabilized, to stop the disease. In the same field, the development of the disease seems to be divided into general and rising period. The so-called universal period, from sporadic disease to spread into a film, horizontal development, that the strain rate increased. The so-called rising period is the lesion gradually spread from the lower stems and leaves of plants, rose to the middle of the leaves and even the parietal lobe and spike, the severity increased. Of course, there is no clear boundary between the two, and as the severity increases, the rate of diseased plants is still on the rise.