对韭蛆高毒力Bt菌株与常用化学杀虫剂相容性研究

Compatibility of a Bt Srain of High Virulence against Bradysia odoriphaga Larvae with Commonly Used Chemical Pesticides

为了明确对韭菜迟眼蕈蚊幼虫(韭蛆)高毒力Bt菌株JQD117与常用化学杀虫剂的相容性,本研究系统阐述了7种常用化学杀虫剂对该菌株芽孢萌发、生长、毒力等影响及混合增效作用。结果表明,在试验设定的化学杀虫剂高、中、低3种浓度存在的情况下,菌株JQD117均能有效萌发,萌发速率与对照无显著差异,且杀虫毒力与对照无差异显著;在化学杀虫剂常规使用剂量范围内,菌株JQD117产活菌数量与对照LB培养基相比无差异显著。低剂量的吡虫啉、氟啶脲、噻虫啉、溴虫腈和高效氯氰菊酯与Bt菌株混用后表现为明显相加作用;低剂量呋虫胺和噻虫胺与菌株JQD117混用后表现为明显增效作用;低剂量噻虫胺、呋虫胺、溴虫腈与菌株JQD117混用3 d后,对韭蛆的校正死亡率分别为95.45%、90.91%和90.91%。可见,菌株JQD117与常用化学杀虫剂在常规使用浓度范围内均具有良好的相容性。本研究为防治韭蛆Bt制剂开发应用提供了新思路,为减少农药投入量和韭菜安全生产提供了理论依据。

The compatibility of a Bt strain JQD117 showing high virulence against Bradysia odoriphaga larvae with commonly used chemical pesticides was investigated in terms of pesticide effect on spore germination, growth and virulence of the Bt strain. Test results showed that at high, mediate and low concentrations of the pesticides, the strain could germinate at rates not significantly different from that in the control, and showed no significantly different virulence compared with the blank control. When exposed to the routine application concentrations of the chemical pesticides, the strain produced similar number of living bacteria with the strain on LB medium. When the JQD117 was mixed with imidacloprid, chlorfluazuron, chlorfenapyr, thiacloprid and beta cypermethrin at low dose, the mixture showed virulence of obvious additive effect; and when the strain was mixed with dinotefuran and clothianidin at low dose, the mixture showed obvious synergy effect. When mixed with clothianidin, dinotefuran, chlorfenapyr at low dose for 3 d, the mixture resulted in adjusted mortalities in B. odoriphaga of 95.45%, 90.91% and 90.91%, respectively. Thus, the Bt strain JQD117 has good compatibility with chemical pesticides at routine application concentrations. This research provides prospect for reducing pesticide inputs and safety production.