本文以水稻上的主要害虫白背飞虱Sogatella furcifera(Horvath)为研究对象，以田间常用的有机磷类、氨基甲酸酯类、拟除虫菊酯类、新烟碱类、苯基吡唑类等杀虫剂为主要的研究药剂，监测了白背飞虱的田间抗药性情况，利用室内饲养品系建立了白背飞虱对多种药剂的敏感基线，同时在测定各种单剂对白背飞虱毒力的基础上，进行了大量的药剂混配试验，筛选出了一些具有显著增效作用的混配组合。为进一步实施白背飞虱的抗药性监测和治理奠定了基础。 一、白背飞虱敏感品系的建立 本文利用2007年7月采自南京江浦农场的白背飞虱，在室内不接触任何药剂的情况下连续饲养，进行敏感品系的培育。饲养13代后，测定其敏感性发现，白背飞虱对吡虫啉、呋虫胺、吡蚜酮和啶虫脒等新型杀虫剂均表现出较高的敏感性，但对乙酰甲胺磷和毒死蜱等有机磷杀虫剂的敏感性则不高。通过与已报道的杀虫剂敏感资料进行对比分析，发现本研究培育的白背飞虱室内饲养品系已经达到敏感品系水平，在研究白背飞虱对新型杀虫剂抗药性时，可以作为相对敏感品系使用，所测定的吡虫啉(0.05ng/头)、溴氰菊酯(1.90 ng/头)、丁硫克百威(1.32 ng/头)和氟虫腈(0.13 ng/头)等杀虫剂的LD50值可以作为敏感基线资料使用。 二、白背飞虱田间种群抗药性的监测 本文采用点滴法监测了我国3个地区的田间白背飞虱种群对有机磷类、氨基甲酸酯类、吡啶甲亚胺杂环类、苯基吡唑类、昆虫生长调节剂类和新烟碱类6类9种主要杀虫剂的抗性水平。结果表明，不同地区的白背飞虱对氟虫腈均已产生了中等水平的抗性(RR:10.31-20.54倍)，南京种群对丁硫克百威(23.26倍)也表现出一定的抗性，但其他药剂均没有产生明显的抗性，仅在不同地区种群表现为丧失敏感性或低水平抗性。进一步比较不同地区白背飞虱种群对不同杀虫剂的抗性差异发现，只有南京地区的白背飞虱对丁硫克百威的抗性偏高、对毒死蜱偏敏感，其他监测的药剂在不同地区间不存在抗性水平的显著差异，表现出迁飞害虫的抗性特征。 三、吡虫啉与常规杀虫剂混配对白背飞虱的联合作用 吡虫啉是目前防治白背飞虱最好的药剂之一，为了延长其使用寿命，本文研究了吡虫啉与常规杀虫剂的联合毒力作用，结果发现吡虫啉和常规杀虫剂混用没有发现拮抗作用，调整混合比例，均可以筛选出增效明显的混用组合。如吡虫啉+丁硫克百威(1:10)、吡虫啉+毒死蜱(1:200)、吡虫啉+溴氰菊酯(1:10)和吡虫啉+噻嗪酮(1:5)，它们的共毒系数分别达到278.28、225.09、224.26和230.18，增效显著。进一步研究剂型，部分混配组合可以开发成具有市场潜力的复配制剂。 四、噻嗪酮和毒死蜱与其他常规杀虫剂混配对白背飞虱的联合作用 噻嗪酮为昆虫生长调节剂类杀虫剂，对白背飞虱的速效性较差，但是毒力较高。毒死蜱为传统的有机磷类杀虫剂，毒力较差，但田间抗性水平不高。本节研究噻嗪酮与其他杀虫剂之间的混配,同时开展毒死蜱与对白背飞虱具有较高毒力的杀虫剂阿维菌素和氟虫腈的混配,结果发现噻嗪酮与乙酰胆碱酯酶抑制剂类杀虫剂的混配具有一定的增效作用，同时提高了噻嗪酮的速效性，毒死蜱与氟虫腈的组合也具有显著地增效作用。通过研究不同配比的杀虫剂两两混配，发现“噻嗪酮+毒死蜱(1:10)”、“噻嗪酮+乙酰甲胺磷(1:10)”、“噻嗪酮+丁硫克百威(1:3)”、“噻嗪酮+丁硫克百威(1:5)”、“氟虫腈+毒死蜱(1:5)”和“氟虫腈+毒死蜱(1:10)”这6个混配组合都表现出明显的增效作用，它们的共毒系数分别达到了200.33、250.32、211.57、274.77、251.51和248.05。

In this paper, the white backed planthopper (WBPH), Sogatella furcifera (Horvath), was studied for its resistance to different insecticides. A susceptible strain was cultured and baseline data for several insecticides were tested. Then, the resistance of WBPH was monitored with three field populations, efficient insecticides and synergistic mixtures were screened. Some interesting results were obtained and founded the bases for further researches of the resistance in WBPH. 1 Setup on susceptible strain of S. furcifera S. furcifera collected from a paddy field in Nanjing city in China in 2007 was reared in the laboratory condition without contacting any insecticide for 13 generations. Then the susceptibility of S. furcifera to different insecticides was tested. The results showed that S. furcifera was very sensitive to the newly introduced insecticides, such as imidacloprid, dinotefuran, pymetrozine and acetamiprid, while less sensitive to the organophosphates, such as acephate and chlopyrifos. Comparison with the susceptible strains previously reported, it was found that the laboratory strain had recovered its susceptibility to different insecticides and could be used as relatively susceptible strain in resistance researches. The obtained LD50 value of imidacloprid (0.05ng/pest), deltamethrin (1.90 ng/pest), carbosulfan (1.32 ng/pest) and fipronil (0.13 ng/pest) could be used as baseline data. 2 Resistance in field populations of S. furcifera Resistance to 9 insecticides in 3 field populations of S.furcifera was evaluated. The results determind by topical application showed that all the populations exhibited moderate level of resistance to fipronil (RR ranged from 10.31 to 20.54). Otherwise, no obvious resistance was found among the populations and the insecticides tested, except that the hoppers collected from Nanjing city showed moderate resistance to carbosulfan (RR:23.26 folds). Further comparison of the resistance of different populations to various insecticides found that different geographic populations did not show obvious difference in resistance to various insecticides, except for Nanjing population exhibited a little higher resistance to carbosulfan and susceptibility to chlorpyrifos. These could be well explained by the migration characteristics of the pest. 3 Synergistic effect of imidacloprid mixed with other insecticides Imidacloprid was one of the most effective inseciticides for control of S. furcifera at present. In order to delay the resistance and extend the use life of imidacloprid with mixtures, synergistic effect of imidacloprid mixed with other insecticides were studied. The results showed that no antagonism effects existed in the mixtures of imidacloprid and other insecticides tested. And synergistic couples could be selected through changing the ratio of the ingredients. Imidacloprid and carbosulfan with the ratio of 1:10, ihlopyrifos with the ratio of 1:200, deltamethrin with the ratio of 1:10 and buprofezin with the ratio of 1:5 all showed highly synergism with 278.28, 225.09, 224.26 and 230.18 of co-toxicity coeffeciency, respectively. After more studies of the formulations, these synergistic mixtures should be developed to the mixture insecticides with good market potential. 4 Synergistic effect of buprofezin or chlopyrifos mixed with other insecticides Buprofezin was an insect growth regulator with high toxicity to S. furcifera, but lower acute toxicity. Chlopyrifos was an organophosphorus insecticide with low toxicity to S. furcifera and low resistance in field populations. For enhancement of their efficiency, buprofezin mixed with other insecticides and chlopyrifos mixed with abamectin or fipronil were studied in this work. The resulted showed that the mixtures of buprofezin and AChE inhibitors not only showed good synergistic effect, but also enhanced acute toxicity. The mixture of chlopyrifos and fipronil also showed synergistic effect. The co-toxicity coeffeciency of the mixture couples of buprofezin with chlopyrifos (1:10), with acephate (1:10), with carbosulfan (1:3 and 1:5) was 200.33, 250.32, 211.57and 274.77 respectively. The mixture of fipronil and chlopyrifos with the ratio of 1:5 and 1:10 showed also higher synergistic effect (251.51 and 248.05, respectively).