阿维菌素B2a对南方根结线虫的活性评价

Evaluation of Avermectin B2a for Activity against Meloidogyne incognita

[目的]对阿维菌素B2a防治南方根结线虫的活性进行评价,并探索其作用机理,为其作为杀线剂的开发利用提供技术支撑。[方法]室内测定B2a对南方根结线虫2龄幼虫(J2)和卵的活性,并通过清洗试验考察B2a杀线作用的可恢复性。[结果]B2a杀线效果显著优于杀线威,B2a处理2、24h的LD50值分别为0.79、0.52mg/L,杀线威的EC50值分别是其15.81、20.48倍。恢复性试验结果表明,处理时间超过2h后,B2a对J2产生不可逆致死作用,这表明了B2a和之前报道的B1a相同,均为线虫"致死剂"而非"线虫麻痹剂";在卵抑制试验中,B2a可有效降低南方根结线虫卵的孵化,B2a在质量浓度为2mg/L时,卵在第2、5、7天卵孵化率降低了91.82%、94.33%和94.16%。[结论]B2a对侵染态的根结线虫有较强的致死作用,可高效抑制卵的孵化。此外,需要进一步的田间数据来确定其应用前景。

[Aims] This paper aims to evaluate the activity of avermectin B2a against southern root-knot nematode and explore its mode of action and to provide technical guidance for its future application as nematicide. [Methods] The activity in laborary of B2a was measured against two-stage juvenies（J2） and eggs, and the action reversibility of B2a was explored by rinse experiment as well. [Results] The results indicated that the control effect against J2 of B2a was significantly better than oxamyl, with LD50 of 0.79 and 0.52 mg/L when exposing time is 2 and 24h respectively.Through recovery experiment, it was confirmed that the lethal effect of B2 a on J2 s is irreversible when exposing time is above 2h, which showed that MOA is different from traditional non-fumigant nematicide. Meanwhile, B2a could effectively reduce the hatching of the eggs of the Meloidogyne incognita. The hatching rate decreased by 91.82, 94.33 and 94.16% on 2nd day, 5th day and 7 th day respectively, when the exposing concentration of B2a was 2mg/L.[Conclusions] B2a has a strong lethal effect on infective J2s, and can effectively inhibit the hatching of eggs. In addition, further field data is needed to be determined to confirm its application prospects.