农药对稻田捕食性天敌泽蛙的安全性研究

SAFETY STUDY OF PESTICIDES ON BOG FROG,A PREDATORY NATURAL ENEMY OF PEST IN PADDY FIELD

1981～1989年用百余种农药对稻田害虫天敌泽蛙(Rana limnocharis)的蝌蚪、幼蛙和成蛙进行了毒性测定和田间试验,发现杀虫剂的安全性比杀菌剂、除草剂要小.从药量安全指数和48h 的LC_(50)值来看,杀虫剂中拟除虫菊酯类、有机氯类以及沙蚕毒素、杀虫环、杀螟丹、嘧啶硫磷、治螟磷、百菌清、菲醌、苏化911、五氯酚钠、毒草安等品种安全性小.乳油剂的安全性比可湿性粉剂小.混合制剂及不同作用机制的药剂混配安全性变小.泽蛙对农药敏感,尤以蝌蚪最敏感.农药对泽蛙蝌蚪急性毒性可分3类,室内48h LC_(50)值小于1ppm,田间48h 药量安全指数小于0.5时,为高毒类;室内LC_(50)为1～10ppm,田间48h 药量安全指数为0.5～2.5时,为中毒类;室内LC_(50)大于10ppm,田间48h 药量安全指数大于2.5时,为低毒类.

During 1981 to 1989,116 kinds of pesticides were used in laboratory and fieldto test their toxicity on bog frog(Rana Limnocharis).It was found that the toxicity variedwith different pesdicides,their mixture and formulation.The insecticides were more toxic tobog frog as compared with fungicides and herbicides.The results also indicated that the fol-lowing pesdicides are highly toxic:Pyrethroid,Organochlorine and Nereistoxin,Evisect,Padan,Pirimiphos ethyl,Sulfotep,Chlorothalonin,PCP-Na,Propachlor etc.Pesticide mix-tures are more toxic than single compound.Emulsifiable concentrate is more toxic than wet-table powder.Bog frog is very susceptible to pesticides,especially its tadpoles.According tothe value of LC_(50)(48 h)and DSR,the dosage safety ratio of pesticides to tadpoles was evaluat-ed.The standards in laboratoy can be expressed in the following:low toxicity,LC_(50)>10 ppm;moderate toxicity,1～10 ppm;high toxicity,LC_(50)<1 ppm.In field evaluation standards,interms of DSR(dosage safe ratio,48 h)are as follows:low toxicity,DSR>2.5;moderate toxi-city,0.5～2.5;high toxicity,<0.5.