二化螟对三唑磷的抗性发生动态与风险评估

对浙江省苍南县稻田第一代二化螟的抗药性进行了3年的监测。结果表明：二化螟对三唑磷、灭多威和阿维菌素的抗药性上升迅速，尤其是对三唑磷的抗性达到极高抗水平（2367．3）；对水胺硫磷与甲胺磷抗性变化不大；而对氟虫腈的抗性则有所下降。在室内用三唑磷对采自浙江省苍南县的二化螟进行连续14代筛选，结果抗性由203．3倍上升到3272．6倍，室内三唑磷筛选抗性的现实遗传力（h^2）为0．3105，表现出较大的抗性风险。生物适合度的实验表明，抗性品系、田间抗性种群的生物适合度均低于敏感品系。在抗性筛选过程中，当抗性达到1523．7倍（第9代）时，停止筛选，5代后抗性水平下降到327．1倍并保持相对稳定；恢复筛选后，抗性水平又上升。表明二化螟对三唑磷的抗性应采取早期治理。

Dynamics and risk assessment of triazophos resistance in rice stem borer (Chilo suppressalis Walker)

The resistance of the rice stem borer(Chilo suppressalis Walker)against conventional pesticides in Cangnan County,Zhejiang Province was monitored continuously from 2002 to 2004.The results indicated that the resistance to triazophos,methomyl and abamectin increased fast,of which the resistance to triazophos had reached a very high level(RR:2 367.3).The resistance to isocarbophos and methamidophos increased little and that to fipronil decreased.The rice stem borer collected from this area was continuously selected with triazophos in laboratory.After selection for fourteen generations,the resistance to triazophos increased from 203.3 to 3 272.6 times.The realized heritability(h~2)of resistance was estimated as 0.310 5,indicating a high risk for rice stem borer to develop resistance to triazophos.Analysis of population growth tendency index revealed that resistant borers had less fitness.When the borers were selected to super high resistant(RR:1 532.7),stopping selection made the resistance decrease quickly to 327.1 in the following 5 generations and tend to be stable.Then re-selection made the resistance increase again.So,it is suggested that management of triazophos resistance should be carried out at the early stage of resistance development.