不同施用方式下昆虫病原线虫对小地老虎的防治作用

The control effect of entomopathogenic nematodes with different application methods against Agrotis ypsilon Rottember

小地老虎是重要的地下害虫,严重为害烟草、玉米、棉花等作物。为促进昆虫病原线虫在小地老虎防治中的使用,以云南当地品系与商业品系为材料,调查了3种施用方式(悬液、悬液+覆盖刨花、虫尸剂)下昆虫病原线虫防治小地老虎保护烟苗的效果,并根据后续埋入的大蜡螟死亡情况评估昆虫病原线虫在土壤中的存活情况。盆栽试验结果表明,喷施悬液7 d后,两个商业品系的昆虫病原线虫Steinernema carpocapsae All(Sc All)和Heterorhabditis indica LN2(Hi LN2)保苗效果显著。各施用方式处理保苗效果由高到低为悬液>悬液+覆盖刨花>虫尸剂。田间试验结果表明,处理7 d后,Sc All悬液处理效果优于所有品系的虫尸剂处理效果,烟苗死亡率与化学农药氯氰菊酯相当,直接施用Sc All悬液能较好地抑制小地老虎对烟苗的为害,而虫尸剂释放的昆虫病原线虫存活时间较长,可针对不同的防治窗口期结合应用。

Agrotis ypsilon Rottemberg is a worldwide soil-dwelling agricultural pest of great economic significance, causing severe damage to tobacco, corn, cotton, and other crops. To improve the use of entomopathogenic nematodes(EPN) in the prevention and control of A. ypsilon larvae, we evaluated the protective effect of one Yunnan native and two commercial EPN strains with different application methods: aqueous nematode suspensions(Aq), Aq + wood shaving cover(AqCo),nematode-infected insect cadaver(Ca). The survival of EPN in soil was evaluated according to the mortality of buried Galleria mellonella, which provided a reference for improving the application of EPN to control A. ypsilon in the field. The results of pot experiments showed that the efficacy of different application treatments in protecting tobacco seedlings from high to low was Aq, AqCo, and Ca. The two commercial strains(Steinernema carpocapsae All and Heterorhabditis indica LN2) had better control effects on A. ypsilon compared to the control, seven days after spraying the suspensions. In the field experiment, the commercial strain S. carpocapsae applied as aqueous suspension resulted in a better control effect than all Ca treatments and caused the lowest mortality of tobacco seedlings which was comparable to that of the chemical pesticide cypermethrin treatment.