几种药物复配对白蚁的毒力和联合作用测定

目的研究一些新型药剂复配后对白蚁是否有增效作用,为科学开发应用白蚁防治复配剂提供理论依据。方法先把药物单剂用丙酮配制成系列浓度的药液,滴加在滤纸上形成药膜,投入工蚁持续接触,定期检查工蚁的死亡率,求出96 h后的LC50,然后把2种药物单剂的最高浓度按等毒比或其他比例进行混配,稀释成系列浓度,求出复配剂的LC50值和共毒系数,根据孙云沛法判定混剂的联合作用情况。结果噻虫嗪、阿维菌素、甲维盐、氟虫腈、虫螨腈、联苯菊酯这6种药剂,96 h内联苯菊酯对散白蚁的毒力最高,噻虫嗪对散白蚁的毒力最低,LC50分别为0.919、111.378 mg/L。对乳白蚁来说,虫螨腈的毒力最高,噻虫嗪的毒力最低,LC50分别为1.868、404.891 mg/L。6种药对散白蚁的毒力均比对乳白蚁的高。虫螨腈、氟虫腈和噻虫嗪这3种药剂两两混配对乳白蚁均有显著的增效作用,共毒系数在320.8~857.4之间。联苯菊酯分别与虫螨腈、噻虫嗪、氟虫腈混配对散白蚁和乳白蚁均有增效作用,共毒系数最低的为183.9,最高的为792.9。阿维菌素、甲维盐与其余药剂的混配对散白蚁和乳白蚁的联合作用大多数为拮抗作用和相加作用,个别为少量的增效作用(增效作用的共毒系数为142.6和188.7)。结论药物混配后对散白蚁、乳白蚁的联合作用有显著的增效作用、轻微的增效作用、相加作用及拮抗作用。复配剂对白蚁是否有增效作用及增效作用的大小,不仅和药物种类及混配比例有关,而且和白蚁种类有关。

Toxicity of some termiticides and joint action of their mixtures against termites

Objective To study toxicity of some termiticides and joint action of these termiticides mixtures against termites. Methods 1 ml diluted solution of a component dissolved with acetone was added on a piece of filter pa- per. Workers termite of Reticulitermes chinese Snyder and Coptotermes formosanus were put into petri dish contained with the treated paper. The death of termites was checked regularly, and the LC50 s were calculated. The highest con- centration of two components were mixed at different proportions and diluted into 4 - 5 concentrations with acetone. The LC50s and co-toxicity coefficient（ CTC ） of the binary mixtures were determined according to the method of Sun. Results Among 6 components of thiamethoxam, abamectin, emamectin benzoate, fipronil, chlorfenapyr and bifenthrin, bifenthrin held the highest toxicity and thiamethoxam held the lowest toxicity against Reticulitermes chinese Snyder after 96 h with the LCs0 of 0. 919 and 111. 378 mg/L respectively;For Coptotermes formosanus,the LC50 of chlorfenapyr was 1. 868 mg/L and showed more toxic to termites than other components,while the LC50 of thiamethox- am was 404. 891 mg/L, the lowest toxicity to termites. The binary mixtures among thiamethoxam, fipronil, chlorfenapyr showed significant synergism against Coptotermes formosanus with CTC between 320.8 and 857.4. When bifenthrin was mixed with a component of thiamethoxam, fipronil or chlorfenapyr, the synergism was always found for two species of termites with CTC 183.9 -792.9. While abamectin, emamectin benzoate were mixed with a component of other 4termiticides separately to form binary mixtures, most of them showed summation and antagonism against two species of termites, others had slight synergism with CTC142.6 and 188.7. Conclusion The binary mixtures of above 6 compo- nents show significant synergism, slight synergism, summation and antagonism against termites and their joint action not only relate to the type of component and the ratio of component in mixture, but also depend on species of termites.