寒地水稻主栽品种稻瘟病流行规律

稻瘟病是危害我国水稻生产的四大主要病害之一。在自然发病条件下，研究了黑龙江省抗、感不同和熟期不同的6个生产主栽品种稻瘟病的流行规律，分析空气温度、相对湿度、降雨量、雨日数以及初始发病率等多种流行因素对发病率的影响。结果表明，不同熟期品种，感病品种叶瘟及穗颈瘟发病时间早、发展速度快、发病程度高，发病时间比抗病品种早7～10 d，供试品种田间稻瘟病的流行规律可用Logistic模型描述。分别建立了不同抗、感品种的稻瘟病叶瘟和穗颈瘟的预测模型，其中在黑龙江省水稻生产季节雨日和相对湿度对田间稻瘟病的流行速度影响最大，是稻瘟病流行的限制因子。

Blast epidemic dynamics occurred in main rice varieties in cold regions

Rice blast is one of the four major diseases in rice production in China. Under natural infection conditions, the occurrence of rice blast in 6 varieties with different resistance levels and maturity, was studied. The effects of epidemic factors on disease rate were analyzed, including air temperature, relative humidity, rainfall, raining days and initial disease rate. The results showed that the occurrence of rice blast in susceptible varieties was earlier (7-10 days), more severe and faster than in resistant varieties. The epidemic dynamics of rice blast in test varieties could be described with Logistic model. The forecast models of leaf and neck blast in different resistant varieties and susceptible varieties were established. The rainy days and relative humidity imposed the greatest impact on rice production in Heilongjiang Province, which are the limiting factors for occurrence of rice blast.