Ladonni H
Medical Entomology Department, School of Public Health, Tehran University of Medical Sciences, Iran.
Med Vet Entomol. 2000 Jun;14(2):213-6. doi: 10.1046/j.1365-2915.2000.00233.x.
For the German cockroach, Blattella germanica L. (Dictyoptera: Blattellidae), the permethrin resistance ratio (RR) was assessed by topical application and by tarsal contact tests, using first-instar nymphs of five strains from Tehran, Iran. Each test was replicated three or four times with 10 nymphs aged 2-3 days; mortality was scored 24h post-treatment. The reference susceptible strain showed LD50 permethrin 0.0175 microl/nymph from topical application, KT50 of 8.41 min and LT50 of 12.82 following tarsal contact with permethrin 15 mg/m2. In four wild strains (F1 generation) the RR varied from 4.14 to 4.7 for mortality after topical application, from 4.2 to 6.45 for mortality and 17-27 for knockdown following tarsal contact tests. Hence, overall knockdown results gave much higher RRs than for mortality data. Resistance ratios based on both methods of treatment were very similar: one strain showed a slightly higher value by topical application (RR 4.6 vs. 4.2, i.e. 1.1-fold difference) whereas the other three strains gave slightly greater RR (1.2-1.4 fold) by tarsal contact. Resistance was abolished by cotreatment with the synergist piperonyl butoxide plus permethrin (ratio 3:1 required for full efficacy), indicating that mixed-function oxidases were inhibited as a major metabolic pathway in all four resistant strains.
对于德国小蠊（Blattella germanica L.，蜚蠊目：姬蠊科），使用来自伊朗德黑兰的5个品系的一龄若虫，通过局部涂抹和跗节接触试验评估了氯菊酯抗性比率（RR）。每项试验用10只2 - 3日龄的若虫重复进行3或4次；在处理后24小时记录死亡率。参考敏感品系经局部涂抹氯菊酯的半数致死剂量（LD50）为0.0175微升/若虫，与15毫克/平方米的氯菊酯进行跗节接触后的击倒中时（KT50）为8.41分钟，半数致死时间（LT50）为12.82分钟。在4个野生品系（F1代）中，局部涂抹后死亡率的RR在4.14至4.7之间，跗节接触试验后死亡率的RR在4.2至6.45之间，击倒率的RR在17至27之间。因此，总体击倒结果的RR比死亡率数据高得多。基于两种处理方法的抗性比率非常相似：一个品系通过局部涂抹显示出略高的值（RR为4.6对4.2，即1.1倍差异），而其他三个品系通过跗节接触的RR略高（1.2 - 1.4倍）。与增效剂胡椒基丁醚加氯菊酯共同处理可消除抗性（完全有效需要3:1的比例），这表明在所有四个抗性品系中，混合功能氧化酶作为主要代谢途径受到抑制。
