半夏块茎腐烂病病原鉴定和药效比较

Pathogen identification of Pinellia ternata tuber disease and selection of fungicide

目的：研究半夏块茎腐烂病的病原和控制该病害的发生，为半夏栽培提供依据。方法：分离鉴定采用柯赫氏法则；菌丝生长条件采用二因子饱和D-最优设计；室内药效比较采用菌丝生长速率法。结果：形态学观察和致病性测定表明，引起半夏块茎腐烂病的病原物为尖孢镰刀菌Fusarium oxysporum ；F. oxysporum 菌丝生长的适宜温度为15～30℃，最适温度为21.9℃，适宜pH值为6～8，最适pH 7.2；室内药效比较表明，70%甲基托布津和58%甲霜灵锰锌对F. oxysporum 菌丝生长的抑制效果最好，EC50分别为0.0027 g？L-1、0.0662 g？L-1。结论：明确了半夏块茎腐烂病病原，为该病害的防治提供了依据。

The rotten tuber of Pinellia ternata was found as an important disease during the growing season in Tianshui production area. The isolated pathogens were tested following Koch’s postulates and identified as Fusarium oxysporum. The suitable growth conditions for the F. oxysporum were 15-30 ℃, pH 6-8, the optimal condition was21.9 ℃ and pH 7.2. Some fungicides were demonstrated to be effective to inhibit the pathogen growth. 70% thiophanate-methyl and 58% metalaxyl MZ were most effective to inhibit the pathogen. The EC50 were 0.002 7, 0.066 2 g·L-1, respectively.