寄主生育期、接种条件对玉米弯孢菌叶斑病发生的影响

为了明确不同因子对玉米弯孢菌叶斑病发生的定量影响,采用室内离体叶片及田间接种方法,通过人工控制不同生育期及接种条件,定量研究了不同因子对玉米弯孢菌叶斑病发生的影响。结果表明,玉米感病性随生育期的延长而增加,单位面积叶片上的病斑数随接种浓度的增大而增加,并随接种浓度呈直线增长。当叶面保湿时间大于8 h时,叶面保湿时间越长病斑数越多,其变化呈逻辑斯蒂模型趋势。温度对病害的潜育期有重要影响,在10~35℃时,温度越高潜育期越短。不同接种量对玉米弯孢菌叶斑病的病情发展动态有重要作用,低浓度下接种,病害的病情发展曲线近似为直线,增长较为平缓;高接种量条件下,病情增长较为迅速,接近S型曲线。

Effects of development stage, inoculation conditions on occurrence of Curvularia leaf spot of maize

To understand quantitative effects of different factors on occurrence of Curvularia leaf spot of maiza,methods of detached leaves inoculation and field inoculation were used. It was suggested that the susceptibility of maize increased with the growing days of maize by the experimental results of detached leaves and field inoculation. The number of spots on maize leaves increased with the increasing of inoculum density and the relationship between the number of spots and inoculum density could be described by linear model. With the extension of leaf wetness duration,the number of spots also increased. The changing trend of the number of spots and leaf wetness duration could be described by logistic model. Length of incubation was significantly affected by temperature which would shorten with increasing of temperature. Various inoculum densities had significant influence on the epidemic of Curvularia leaf spot of maize. Under the low inoculum density,the epidemic curve of Curvularia leaf spot approximated to be a line and the epidemic speed was mild. When the inoculum density was high,the epidemic speed was more rapid and the epidemic curve was close to the S shape.