云南省玉米灰斑病菌孢子相关生物学特性研究

为探明玉米灰斑病在云南省发病较重的原因,该试验在田间条件下,采用人工喷雾接种玉米灰斑病菌,研究玉米灰斑病潜育期、病斑产孢、孢子飞散以及菌龄、温度、湿度和光照对孢子萌发的影响.结果表明:昆明地区玉米灰斑病在感病品种会单4号上的潜育期为12～13d;病斑产孢量随显症天数的增加呈单峰曲线,显症后24～27d病斑产孢量达到最大值;玉米灰斑病菌孢子主要在夜间飞散,风或雨有助于孢子的飞散与传播;菌龄对孢子萌发影响较大,随菌龄的增长,孢子萌发率降低;在10～30℃时,分生孢子均能萌发,但以22℃最适,35℃以上或4℃时均不能萌发;水滴有利于孢子萌发,光照对孢子萌发影响较小.

Characterization of Biology Related to Conidia of Cercospora zeae-maydis in Yunnan

To understand why gray leaf spot(GLS) is very serious in Yunnan,artificial inoculation of conidia of Cercospora zeae-maydis was conducted in the field for observing its latent period,sporulation of lesion,spore release,and the effect of hyphal age,temperature,moisture and lighting on spore germination.The results showed that the latent period of GLS varied from 12 to 13 days on the susceptible cultivar Huidan 4 in Kunming and its lesion sporulation increased with the days after lesion appearance but showed a unimodal curve trend and reached the highest level in 24 to 27 days.The spores of GLS mainly released at night,and their release and spread were promoted by windy or rainy weather.Hyphal age greatly affected spore germination with the trend that the germination rate decreased as the hyphae got older.Conidia could germinate at 10~30 ℃,the optimal temperature being 22 ℃,but failed to germinate at a temperature at or higher than 35 ℃ or at or lower than 4 ℃.Water drop was beneficial to spore germination while lighting had little influence on it.