为明确溴虫腈与哒螨灵的联合杀螨活性,采用玻片浸渍法测定了溴虫腈与哒螨灵不同配比混剂对朱砂叶螨雌成螨的杀螨活性,并以共毒因子法和共毒系数法评价混剂的增效作用。结果表明,溴虫腈和哒螨灵对朱砂叶螨雌成螨处理后24 h的致死中质量浓度( LC50)分别为8.80、17.69 mg/L；溴虫腈与哒螨灵的质量比为49∶51、47∶53、45∶55时增效最明显,对朱砂叶螨处理后24 h的共毒系数分别为177.94、178.49、173.73,LC50分别为6.65、6.72、7.00 mg/L,其毒力分别是哒螨灵的2 .66倍、2 .63倍、2.53倍。因此,45%~49%溴虫腈与51%~55%哒螨灵混合具有显著的增效作用。%To investigate the joint acaricidal activities of chlorfenapyr and pyridaben,the acaricidal activi-ties of mixtures containing different proportion of chlorfenapyr and pyridaben against Tetranychus cinnaba-rinus Boisduval were measured via slide dipping,and the synergism was investigated by means of co-toxic-ity factor and co-toxicity coefficients( CTC) . The results indicated that the LC50 values of chlorfenapyr and pyridaben against T. cinnabarinus female adults were 8. 80 and 17. 69 mg/L,respectively. The best syn-ergistic effect was discovered in the ratio 49∶51 ,47∶53 and 45∶55 with the CTCs of 177 . 94 ,178 . 49 and 173. 73,respectively. The LC50 values of the three mixtures were 6. 65,6. 72 and 7. 00 mg/L,respective-ly,and the toxicities were 2. 66,2. 63 and 2. 53 times the toxicity of pyridaben,respectively. Therefore, chlorfenapyr ( 45%—49%) mixed with pyridaben ( 51%—55%) showed strong synergism against T. cinnabarinus female adults.
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