温度和叶面湿润时数对烟草赤星病菌侵染的影响

Influence of Temperature and Leaf Surface Wetness Duration on Infection of Tobacco Alternaria alternata

在控制条件下接种烟草赤星病菌的试验结果表明 ,在品种和菌株组成一定的情况下 ,接种温度 (DT)和叶面湿润时数 (WD)是影响病菌侵染的 2个主要因素。接种温度在 12～ 37℃范围内 ,病菌可以侵染寄主 ,成功侵染的最适温度为 2 7～ 30℃。在适宜温度条件下 ,接种后保湿 2h病菌即可侵入 ,保湿时间延长 ,侵染概率增大。侵染概率与接种温度、叶面湿润时数及其互作之间具有线性关系。

Tobacco leaves at maturing stage were inoculated with conidial suspension (1×10\+5conidia/ml) of Alternaria alternata at different temperatures, 12, 15, 18, 21, 24, 27, 30, 33, 35, and 37℃,for various wetness durations ranging from 0 to 48 hours. Infection probability increased with the increase of wetness duration at same temperature and increased with the increase of temperature up to about 30℃, and then declined. Optimum temperature for infection was in range of 27-30℃. Successful infection required 2 hours of leaf wetness after inoculation. A regression model using the infection probability as a function of the leaf wetness duration and temperature was established.