无可观察效应浓度在赤眼蜂慢性毒性研究中的应用

[目的] 探索无可观察效应浓度(NOEC)作为评价农药慢性毒性影响指标的可行性,为制定农药对赤眼蜂慢性毒性影响试验准则奠定基础。[方法] 用药膜法对3种赤眼蜂(稻螟赤眼蜂、亚洲玉米螟赤眼蜂及松毛虫赤眼蜂)进行急性毒性试验,并在此基础上采用卵卡浸渍法进行慢性毒性试验,探索5种农药(25~400 mg？L-1乐果、10~160 mg？L-1吡虫啉、5 000 mg？L-1氟铃脲、4 000 mg？L-1毒氟磷及2 000 mg？L-1恶唑砜)对药剂敏感性较强的不同虫态赤眼蜂羽化率、寄生率及成蜂存活时间的影响。[结果] 乐果和吡虫啉的NOEC分别为200和20 mg？L-1,高于二者防治水稻飞虱和螟虫田间最高推荐剂量,在应用时应避开赤眼蜂生防时期。5 000 mg？L-1氟铃脲对松毛虫赤眼蜂、4 000 mg？L-1毒氟磷和2 000 mg？L-1恶唑砜对稻螟赤眼蜂卵期、幼虫期、预蛹期和蛹期是安全的。[结论] NOEC作为评价慢性毒性影响指标具有可行性,可作为农药对赤眼蜂慢性毒性影响的重要考察指标。
[Objectives] This research was carried out to explore the feasibility of no observed effect concentration(NOEC)used as an index to evaluate the chronic toxicity of pesticides,which can provide a technical character on formulating the guideline for chronic toxicity of pesticides to Trichogramma spp. [Methods] Glass-vial method was used on acute toxicity to Trichogramma japonicum Ashmead,T.ostriniae Pang et Chen and T.dendrolimi,and host egg exposure method was adopted in the chronic toxicity experiment to explore the chronic effects of five pesticides(25-400 mg？L-1 dimethoate,10-160 mg？L-1 imidacloprid,5 000 mg？L-1 hexaflumuron,4 000 mg？L-1 dufulin and 2 000 mg？L-1ezuofeng)on the different development stage of Trichogramma spp.,such as emergence,parasitism,and longevity. [Results] The NOEC of dimethoate and imidacloprid are 200 and 20 mg？L-1,respectively,which are significantly higher than the maximum recommended dose in the field,so dimethoate and imidacloprid should not be sprayed when Trichogramma spp.was released. Hexaflumuron at the concentration of 5 000 mg？L-1 is non-toxic to T.dendrolimi at egg,larvae,prepupae and pupae stage. Dufulin and ezuofeng,at the concetration of 4 000 mg？L-1 and 2 000 mg？L-1,respectively,is non-toxic to T.japonicum Ashmead at egg,larvae,prepupae and pupae stage. [Conclusions] It is feasible for NOEC as an index to evaluate the chronic toxicity of pesticides to Trichogramma spp.