荔枝霜疫霉菌对烯酰吗啉的敏感性测定

荔枝霜疫霉病是荔枝最重要的病害之一烯酰吗啉用于防治该病害。采用生长速率法测定了烯酰吗啉对2009要2012 年采自广东广西福建和云南等地区的115 个荔枝霜疫霉菌菌株的有效抑制中浓度值（EC50 值结果表明院各菌株的EC50值介于0.0977~0.2226 g/mL 之间，平均为0.1702，0.0026g/mL最不敏感菌株的EC50 值是最敏感菌株的2.28 倍；所有菌株的EC50值频率分布呈连续单峰曲线，表明无抗药性亚群体。

Sensitivity of Peronophythora litchii to dimethomorph

Litchi downy blight caused by Peronophythora litchii is one of the most prevalent diseases of litchi inChina. Dimethomorph has been used to control the disease for more than 10 years. The survey of the fungicide resistancewas conducted in this paper. The median effective concentration (EC50) values of dimethomorph to 115 isolates of P. litchiicollected from Guangdong, Guangxi, Fujian and Yunnan during 2009 to 2012 were tested by mycelia radial growthinhibition method. The results showed that EC50 values ranged from 0.0977 g/mL to 0.2226 g/mL. The average of EC50value was 0.1702 (0.0026) g/mL. The EC50 value of the most insensitive isolate was 2.28 folds of the most sensitive one.The EC50 value frequency of all tested isolates distributed as a continuous unimodel curve. It indicated that there was noresistant subpopulation among these isolates