叶片湿润时间对葡萄霜霉病发生状况的影响

Effect of Different Humidity Time on Occurrence of Plasmopara viticola in Grape

从不同菌悬液与叶片接触时间、接菌后叶片不同保湿时间和不同保湿条件3方面,研究叶片湿润时间对葡萄霜霉病发生状况的影响。结果表明,葡萄霜霉病菌悬液与叶片接触0.5 h以上即可导致霜霉病发生,接触时间越长发病越重;接菌后在RH=76%保湿条件下,葡萄霜霉病即发生,湿度越高发病越重;霜霉病菌完成侵入到显症需要的叶片湿润条件是叶片湿润2～3 h以上;20℃条件下,霜霉病的潜伏期最短2～3 d,而病斑出现的高峰期是使叶背湿润后的5～7 d。

The experiments set up different time of leaves infected by fungal suspension,different humidity time of leaves inoculated by Plasmorara viticola and different humidity condition in laboratory to explore the effect of different thumidity time on occurrence extent of Plasmopara viticola on grape leaves.Results showed that grape downy mildew would take place when grape leaves were infected by fungal suspension beyond 0.5 h and the severity of disease became worse with time enlongation.The humid condition of grape downy mildew was beyond RH 76.00% and disease was worse with higher humid.The key condition for Plasmorara viticola infection and disease apparition was keeping humidity beyond 2-3 h.The shortest incubation period of Plasmorara viticola was 2-3 d at 20 ℃.The highest apparition period of disease was 5-7 d after wetting grape blade back.