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1.
The cross-resistance and biochemical mechanism of the beet armyworm, Spodoptera exigua (Hübner), to spinosad was studied in the laboratory. S. exigua population were collected from Shanghai suburb. After five generations of selection, the resistance of S. exigua to spinosad increased 345.4 times compared with the susceptible strain. There was no cross-resistance between spinosad and fenvalerate, phoxim, methomyl, abamectin, and cyfluthrin. When the inhibitors, PBO, TPP, DEF, and DEM were used as synergist in the susceptible strain and resistant strain, the synergistic ratio was 0.7-, 0.5-, 1.0-, and 0.6- fold for the susceptible strain, and 9.8-, 1.5-, 2.6-, and 1.5-fold for the resistant strain, respectively. The results revealed that PBO had significant synergistic effect on the resistant strain. The activity in vitro of microsomal-O-demethylase and glutathione S-transferase in the resistant strain was 5.2- and 1.0-fold of the susceptible strain, respectively. The results implied that microsomal-O-demethylase might be important in conferring spinosad resistance in the S. exigua population.  相似文献   

2.
烟粉虱对螺虫乙酯的抗性监测及交互抗性测定   总被引：1，自引：1，他引：0  
为明确螺虫乙酯在湖北地区的抗性水平以及与其存在潜在交互抗性风险的常用药剂类型,采用着卵叶片浸渍法,于2013年对湖北省13个烟粉虱MEAM1和MED隐种地理种群对螺虫乙酯的抗药性进行了监测,并以室内敏感品系SUD-S为参照,对经螺虫乙酯连续17代抗性筛选的WH-2种群进行了交互抗性分析。结果表明:湖北省13个烟粉虱地理种群对螺虫乙酯均表现出极低的抗性,LC50介于0.015~0.081 mg/L之间;其中MED隐种WH-2种群对螺虫乙酯的抗性最高,LC50为0.081 mg/L。在室内用螺虫乙酯对MED隐种WH-2种群连续17代抗性筛选后,其对螺虫乙酯的抗性倍数上升约7倍。经螺虫乙酯筛选的WH-2种群对吡虫啉、乙酰甲胺磷、灭多威、氟氯氰菊酯、氰戊菊酯和氟啶虫胺腈均产生了低水平的交互抗性,抗性倍数分别为8.699、7.165、5.317、6.681、2.958、5.662倍,而对毒死蜱和阿维菌素无交互抗性。表明烟粉虱在湖北省部分地区对螺虫乙酯存在低水平抗性,且螺虫乙酯与部分常用杀虫剂存在交互抗性风险。  相似文献   

3.
The toxicity of spinosad, a new insecticide derived from the bacterium Saccharopolyspora spinosa, was evaluated against susceptible and resistant strains of house fly (Musca domestica L.). Spinosad was highly toxic to house flies based on 72-h LD50 values and the symptoms of poisoning were consistent with a neurotoxic mechanism of action. Spinosad was relatively slow acting, with the maximum toxicity noted at 72 h. Piperonyl butoxide and S,S,S,-tribu-tylphosphorotrithioate synergized the toxicity of spinosad by 3·0- and 1·8-fold, respectively, while diethyl maleate had no significant effect. These results suggest that there is a small degree of monooxygenase-mediated spinosad detoxification in house flies, while hydrolases may be only minimally important and glutathione transferases may have no role. There were no substantial levels of cross-resistance detected, except in the LPR strain where a low 4·3-fold cross-resistance was observed. The cyclodiene-resistant OCR strain was 2·7-fold more sensitive to spinosad than the susceptible strain (CS). These results suggest that cross-resistance may not be a limiting factor for the use of spinosad against house flies. © 1998 Society of Chemical Industry  相似文献   

4.
Nerve insensitivity resistance to synthetic pyrethroids was detected in a resistant field strain (JSFX-R) of the cotton bollworm, Helicoverpa armigera (Hübner), using a neurophysiological assay in which extracellular spontaneous neuronal activity was measured in response to cis-cypermethrin. The nerve insensitivity mechanism was selected using a combination of toxicological and neurophysiological methods. The third-instar larvae in selected strains of Family-37 and CTR strain expressed a very high resistance to fenvalerate (RF = 2060-fold and 805-fold, respectively) and high cross-resistance to DDT (RF = 1927-fold and 2384-fold, respectively) which was not affected by two metabolic synergists, PBO and DMC. The frequency of nerve-insensitive individuals detected in neurophysiological assays (54, 81 and 100% for JSFX-R strain, and the selected strains Family-43 and Family-37, respectively) was not only positively correlated (R2 = 0.968) with the frequency of non-PBO-synergisable resistant individuals detected in toxicological tests (37.5, 62.5 and 90% for JSFX-R strain, Family-43 and Family-37, respectively), but also positively correlated (R2 = 0.978) with the frequency of DDT-resistant individuals detected in toxicological tests (40, 67.5 and 93.3% for JSFX-R strain, Family-43 and Family-37, respectively). Analysis of dose–mortality lines to DDT and fenvalerate from F1 hybrids (R♀ × S♂) indicated that nerve insensitivity resistance to DDT and fenvalerate in the CTR strain was inherited in an incompletely recessive pattern. Degree of dominance (D) was estimated to be −0.66 (± 0.06) (DDT) and −0.26 (± 0.04) (fenvalerate). The dose–mortality curves to DDT in back-cross progeny were strongly suggested, by chi-square analysis, to be fitted with those expected of a one-gene model. Evidence for the co-existence of nerve insensitivity and oxidative metabolic resistance mechanisms within individual H armigera and the effects of their interaction on the expression of resistance to fenvalerate are discussed. © 1999 Society of Chemical Industry  相似文献   

5.
An introductory study was conducted to investigate the pyrethroid resistance ofHelicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) strains in Turkey, collected from cotton fields in the Adana and Antalya provinces, through two different synthetic pyrethroid insecticides: lambda-cyhalothrin and esfenvalerate. In addition, the roles of glutathioneS-transferases (GSTs) in this resistance mechanism were analyzed. It was found that whereas resistance ratios for lambda-cyhalothrin (LD50 levels) were 3- and 98-fold increased in the Adana and Antalya strains, respectively, esfenvalerate ratios were 3.3- and 92.3-fold increased in the Adana and Antalya strains, respectively, with respect to the susceptible strain. Furthermore, Adana and Antalya strains showed 2.4- and 2.9-fold higher GST activities than the susceptible strain, respectively. In the Antalya field strain, the minor increase in GST activity compared with the resistance levels implies that GSTs may be not greatly involved in this resistance. It also provides evidence that they could not be the only metabolic mechanism responsible for resistance to lambda-cyhalothrin and esfenvalerate inH. armigera from Turkey. http://www.phytoparasitica.org posting Nov. 16, 2006.  相似文献   

6.
Abamectin resistance was selected in the western flower thrips [Frankliniella occidentalis (Pergande)] under the laboratory conditions, and cross-resistance patterns and possible resistance mechanisms in the abamectin-resistant strain (ABA-R) were investigated. Compared with the susceptible strain (ABA-S), the ABA-R strain displayed 45.5-fold resistance to abamectin after 15 selection cycles during 18 generations. Rapid reversion of abamectin resistance was observed in the ABA-R strain in the absence of the insecticide selection pressure. Moderate and low levels of cross-resistance to chlorpyrifos (RR 11.4) and lambda-cyhalothrin (3.98) were observed in the ABA-R strain, but no significant cross-resistance was found to spinosad (2.00), acetamiprid (1.47) and chlorfenapyr (0.26). Our studies also showed that the esterase inhibitor S,S,S-tributyl phosphorotrithioate (DEF) and glutathione S-transferase inhibitor diethyl maleate (DEM) were not able to synergize the toxicity of abamectin, whereas the oxidase inhibitor piperonyl butoxide (PBO) conferred a significant synergism on abamectin in the ABA-R strain (SR 3.00). Biochemical analysis showed that cytochrome P450 monooxygenase activity of the ABA-R strain was 6.66-fold higher than that of the ABA-S strain. It appears that enhanced oxidative metabolism mediated by cytochrome P450 monooxygenases was a major mechanism for abamectin resistance in the western flower thrips.  相似文献   

7.
BACKGROUND: Spinosad, a relatively new, effective and safe pesticide, has been widely used in pest control over the last 10 years. However, different levels of resistance to this insecticide have developed in some insects worldwide. RESULTS: After continuous selection for 27 generations, a strain (SpRR) of the housefly developed 247‐fold resistance to spinosad compared with the laboratory susceptible strain (CSS). The estimated realised heritability (h2) of spinosad resistance was 0.14. There was no significant difference in the LD50 values and slopes between reciprocal progenies F1 and F1′, and values of 0.33 (F1) and 0.30 (F1′) were obtained for the degree of dominance. Chi‐square analysis from responses of self‐bred (F2) and backcrosses (BC1 and BC2) were highly significant, suggesting that the resistance was probably controlled by more than one gene. Synergists piperonyl butoxide (PBO), diethyl maleate (DEM) and S,S,S‐tributyl phosphorotrithioate (DEF) affected the toxicity of spinosad at a low level, and demonstrated that metabolic‐mediated detoxification was not an important factor in conferring resistance to spinosad in the SpRR strain. CONCLUSION: It was concluded that spinosad resistance in the housefly was autosomal and incompletely dominant, and the resistance was probably controlled by more than one gene. These results provide the basic information for designing successful management programmes for the control of houseflies. Copyright © 2011 Society of Chemical Industry  相似文献   

8.
The toxicity of a promising new insecticide, imidacloprid, was evaluated against several susceptible and resistant strains of German cockroach and house fly. Imidacloprid rapidly immobilized German cockroaches followed by a period of about 72 h during which some cockroaches recovered. After 72 h there was no further recovery. Imidacloprid-treated houseflies were immobilized more slowly than treated cockroaches, with the maximum effect observed after 72 h, and there was no recovery. Based upon 72-h LD50 values imidacloprid was moderately toxic to German cockroaches (LD50 values were 6–8 ng mg-1) and had only low toxicity to house flies (LD50 140 ng mg-1). Piperonyl butoxide (PBO) blocked the observed recovery in German cockroaches. PBO also greatly enhanced the 72-h LD50 of imidacloprid from 43- to 59-fold in cockroaches and 86-fold in house flies. Two strains of German cockroach (Baygon-R and Pyr-R) showed >4-fold cross-resistance to imidacloprid. This cross-resistance could not be suppressed by PBO, suggesting that P450 monooxygenase-mediated detoxication is not responsible for this cross-resistance. Variation in the level of synergism observed with PBO (between strains) suggests the ‘basal’ level of monooxygenase-mediated detoxication of imidacloprid is quite variable between strains of German cockroach. The AVER and LPR strains of house fly showed significant cross-resistance to imidacloprid. PBO reduced the level of cross-resistance in AVER from >4·2-fold to 0·5-fold (i.e. the AVER strain LD50 was half that of the susceptible strain when both were treated with PBO), but PBO did not suppress the cross-resistance in LPR. These data suggest monooxygenases are the mechanism responsible for cross-resistance to imidacloprid in AVER, but not in the LPR strain. © of SCI.  相似文献   

9.
Cross-resistance of a fenvalerate-resistant (R-fenvalerate) strain and an imidacloprid-resistant (R-imidacloprid) strain of the cotton aphidAphis gossypii Glover to methomyl, endosulfan and omethoate was determined on cotton and cucumber in the laboratory. The R-fenvalerate strain had been selected for 16 consecutive generations on cotton, and the R-imidacloprid strain for 12. Compared with the susceptible (S) strains, the resistance in the 17th generation of the R-fenvalerate strain to fenvalerate was 29,035-fold on cotton and 700-fold on cucumber, whereas the resistance in the 13th generation of the R-imidacioprid strain to imidacloprid was 4.7-fold on cotton and 3.6-fold on cucumber. The R-fenvalerate strain did not show any cross-resistance to imidacloprid, methomyl or omethoate on cotton and cucumber, but became slightly cross-resistant to endosulfan (RR [resistance ratio] = 5.8 and 7.4 on cotton and cucumber, respectively). On cotton the R-imidacloprid strain became highly cross-resistant to fenvalerate (RR = 108.9) and slightly cross-resistant to methomyl, endosulfan and omethoate (RR = 6.3, 3.0 and 8.5, respectively). In contrast, on cucumber the R-imidacloprid strain became highly cross-resistant to fenvalerate (RR = 33.5) and slightly cross-resistant to methomyl and omethoate (RR = 7.0 and 3.3, respectively), but did not show any cross-resistance to endosulfan. It appears thatA. gossypii of both resistant strains was more resistant to the tested insecticides on cotton than on cucumber, except for imidacloprid —where the resistance on cotton was not significantly different from that on cucumber.  相似文献   

10.
First-instar Earias vittella (Fab.) larvae were selected with fenvalerate and cypermethrin for 15 successive generations in the laboratory at 28(± 1)°C. The insect developed 7.8-fold resistance to fenvalerate and no resistance to cypermethrin. The fenvalerate-selected strain developed 2800-fold and 1200-fold cross-resistance to endosulfan and carbaryl, respectively. This strain, however, did not manifest cross-resistance to the organophosphorus insecticides, quinalphos, fenitrothion, monocrotophos and malathion, or to the synthetic pyrethroid, cypermethrin. The cypermethrin-selected strain acquired 5-, 4-, and 3-fold cross-resistance to endosulfan, fenvalerate and carbaryl, respectively and no cross-resistance to the above organophosphorus insecticides.  相似文献   

11.
采用Tabashnik的域性状指标分析了新疆MEAM1(Middle-East-Asia-Minor l)烟粉虱隐种对吡虫啉的抗性现实遗传力(h2)和不同致死率下的抗性发展速率,同时测定了抗性种群对不同类型杀虫剂的交互抗性。结果表明,在30%~50%较低的选择压力下,新疆MEAM1烟粉虱隐种连续汰选8代后,对吡虫啉的抗性上升28.01倍,抗性现实遗传力h2为0.429 7。假设田间种群现实遗传力为实验室筛选估算值的1/2,即h2=0.214 9,对新疆MEAM1烟粉虱隐种对吡虫啉的抗性发展速率估算结果表明:在药剂选择压力为50%~60%下,若使其对吡虫啉的抗性增长10倍,则需要生长10~8代;而在药剂选择压力为70%~90%下,若使其抗性增长10倍,则仅需要生长6~4代。表明新疆MEAM1烟粉虱隐种对吡虫啉产生抗性的风险很大。交互抗性测定结果显示:抗性种群对同类型的杀虫剂吡虫清和噻虫嗪分别产生了10.78倍和4.75倍的中等至低水平交互抗性;对多杀菌素、毒死蜱、吡丙醚和高效氯氰菊酯的敏感性有所降低;对阿维菌素、氟啶虫胺腈和乙基多杀菌素等杀虫剂则无交互抗性。  相似文献   

12.
Insecticide resistance inHelicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most important constraints on cotton production in Turkey. We investigated the susceptibility ofH. armigera strains collected from cotton fields in the Adana, Hatay and Antalya provinces to insecticides which are in wide use. LD50 values for tralomethrin, lambda-cyhalothrin, endosulfan, profenofos and methomyl were determined by topical bioassay. At the LD50 levels, resistance ratios for tralomethrin were 24.7-, 19.7- and 15.7-fold in the Adana, Hatay, and Antalya strains, respectively; and for lambda-cyhalothrin were 41-, 20-and 40-fold, respectively. Resistance ratios ranged from 1.2- to 2.1-fold in all field strains for endosulfan, profenofos and methomyl, with no significant resistance. These results suggest the presence of resistance to tralomethrin and lambda-cyhalothrin inH. armigera strains collected from cotton fields, but no resistance to endosulfan, profenofos or methomyl could be observed.  相似文献   

13.
为明确田间使用多杀霉素亚致死浓度对棉铃虫Helicoverpa armigera幼虫的影响,用含多杀霉素亚致死浓度LC25的人工饲料持续饲喂棉铃虫3龄幼虫,并对饲喂后其体重、取食量、累计蛹化率、蛹发育历期和蛹重等生长发育及脂肪体内甘油三脂（triglyceride,TG）含量和相关基因SREBP、FAS和HSL表达情况进行测定。结果表明,多杀霉素对棉铃虫的亚致死浓度LC25为0.21 mg/kg;多杀霉素亚致死浓度处理4~6 d后,棉铃虫3龄幼虫体重分别为0.065、0.263和0.329 g,较对照显著降低;处理6 d后,其取食量为0.082 g,较对照显著降低;处理4~7 d后,其累计化蛹率分别为60.90%、63.20%、65.50%和65.50%,较对照显著降低。多杀霉素亚致死浓度处理后,棉铃虫蛹发育历期由对照9.89 d显著延长至10.74 d,单头蛹重为0.274 g,显著低于对照的0.324 g;其脂肪体TG含量较对照显著降低。多杀霉素亚致死浓度处理24~72 h后,参与脂肪酸合成信号通路中重要基因SREBP和FAS的相对表达量较对照均显著下调,而参与脂肪代谢的重要基因HSL则较对照显著上调。  相似文献   

14.
The fitness cost of spinosad resistance was investigated in the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Laboratory experiments were conducted to compare relative fitness of H. armigera between the spinosad-susceptible and -resistant strains. During the experiments, the average development periods of the resistant strain were lengthened by 4–5 days, reflected in a prolongation of egg, larval and pupal periods. Furthermore, pupal survival, pupal weight, the mean life span of emerged adults, eggs laid and hatched decreased greatly in the resistant strain in comparison with the susceptible strain. Other life-cycle parameters such as larval survival, larval wet weights, prepupal periods, pupation ratio, and sex ratio did not change significantly. As a result, both net replacement rate (R 0) and intrinsic rate of increase (r m) were reduced for the resistant strain. Our results clearly indicated that relative fitness of resistant individuals was reduced in the absence of spinosad. Rational measures including pesticide rotations should be expected to delay development of resistance to spinosad in H. armigera field populations from China.  相似文献   

15.
为了解西花蓟马Frankliniella occidentalis(Pergande)对甲氨基阿维菌素苯甲酸盐的抗性风险,采用生物和生化测定方法研究了西花蓟马甲维盐抗性种群与其它杀虫剂的交互抗性和生化抗性机制。西花蓟马甲维盐抗性种群对阿维菌素有高水平交互抗性,抗性倍数为31.656,对啶虫脒有中等水平交互抗性,为12.182,对吡虫啉、溴虫腈、氯氟氰菊酯、毒死蜱和灭多威有低水平交互抗性,为5.517~8.568,而对多杀菌素无明显交互抗性。增效剂胡椒基丁醚(PBO)、马来酸二乙酯(DEM)、三丁基三硫磷酸酯(DEF)和磷酸三苯酯(TPP)对甲维盐抗性种群和田间种群均有显著增效作用。甲维盐抗性种群多功能氧化酶细胞色素P450和b5含量、O-脱甲基酶、谷胱甘肽S-转移酶和羧酸酯酶活性均显著提高,分别为敏感种群的3.89、3.61、5.32、4.42和1.30倍,表明多功能氧化酶、谷胱甘肽S-转移酶和羧酸酯酶等解毒代谢酶活性的提高是西花蓟马对甲维盐产生抗性的重要机制。  相似文献   

16.
The Colorado potato beetle, Leptinotarsa decemlineata (Say), has developed resistance to many insecticides used for its control, recently including imidacloprid, a neonicotinoid compound. Other neonicotinoids are now being deployed to control this pest. A key point in the strategies of resistance management is the monitoring of resistance and cross-resistance. In the summer of 2003, imidacloprid-resistant adult Colorado potato beetles collected from Long Island, New York, USA were bioassayed using topical applications of imidacloprid and nine other neonicotinoids. Compared to a standard susceptible strain, the Long Island beetles showed 309-fold resistance to imidacloprid, and lower levels of cross-resistance to all other neonicotinoids, despite these never having been used in the field, i.e., 59-fold to dinotefuran, 33-fold to clothianidin, 29-fold to acetamiprid, 28-fold to N-methylimidacloprid, 25-fold to thiacloprid, 15-fold to thiamethoxam, 10-fold to nitenpyram, but less than 2-fold to nicotine. In injection bioassays, high resistance to imidacloprid was also found (116-fold). Piperonyl butoxide partially suppressed resistance to imidacloprid, but the resistance level was still over 100-fold, indicating that other mechanisms were primarily responsible for resistance. Low levels of resistance (8- to 10-fold) were found to the nicotinic activator, spinosad, in an imidacloprid-resistant strain collected from the same field in 2004. The cross-resistance seen with all the neonicotinoids tested suggests that the rotation of imidacloprid with other neonicotinoids may not be an effective long-term resistance management strategy. Rotation with spinosad also carries some risk, but it is unlikely that spinosad resistance in this case is mechanistically related to that for the neonicotinoids.  相似文献   

17.
There was no difference in dose response to abamectin between a laboratory strain of Colorado potato beetle (Leptinotarsa decemlineata (Say))from North Carolina and a multiple resistant strain from Massachusetts (LD50= 1.95 and 1.98 ng larva?1, respectively). Two abamectin-resistant strains were generated by separate means. The mutagen, ethyl methanesulfonate, was used to generate an abamectin-resistant strain (LD50= 29.4 ng larva?1) from the susceptible laboratory strain. The other resistant strain (LD50 = 45.3 ng larva?1) was generated through an intense selection with abamectin of a field strain contained in cages set up in existing potato fields. Resistance ratios calculated from LD50values for the two abamectin-resistant strains were 15-fold and 23-fold, respectively. Resistance ratios calculated from LD97values (21-fold and 38-fold, respectively) were higher than those calculated at LD50. Also, there were larvae in both resistant strains which were capable of surviving doses up to 100 ng larva?1, while the susceptible strain had no survivors at 10 ng larva?1. Although the logit mortality regression analysis produced statistically different lines for the two abamectin-resistant strains, the slopes of each appear to be the same. Both resistance factors were determined to be autosomal and incompletely recessive (0.26 to 0.4, respectively) via reciprocal F1crosses to the susceptible laboratory strain.  相似文献   

18.
Comparisons with standard susceptible insects showed that a strain of Tribolium castaneum, with a specific resistance to malathion and its carboxylic ester analogues, had no cross-resistance to topical applications of natural pyrethrins. Another strain of T. castaneum, showing resistance to many organophosphorus (OP) insecticides, was cross-resistant to pyrethrins ( × 34) and eight synthetic pyrethroids also applied topically; least cross-resistance occurred with resmethrin ( × 2.2), bioresmethrin ( × 3.3) and phenothrin ( × 4.0). Generally larger resistance factors were recorded with formulations synergised by piperonyl butoxide (PB). The greatest cross-resistance encountered was with unsynergised tetramethrin ( × 338). Apart from tetramethrin, factors of synergism did not exceed 5.7 with either the susceptible or multi-OP resistant strains. PB antagonised six of the nine pyrethroids against the multi-OP resistant strain. Antagonism also occurred with two of these six, permethrin (cis: trans ratio 1:3) and 5-prop-2-ynylfurfuryl ( 1RS)-cis,trans-chrysanthemate (‘Prothrin’), against the susceptible strain. Considering only formulations without the synergist, the most effective compounds against the susceptible strain, relative to pyrethrins, were bioresmethrin (2.7) and permethrin (2.4). Similarly with the multi-OP resistant strain the most effective compounds were bioresmethrin (28), resmethrin (14) and permethrin (6.6). Thus the LD50 (the dose required to kill 50% of the test species) for bioresmethrin against the resistant strain (0.14 μg) only slightly exceeded the LD50 for pyrethrins against the susceptible strain (0.12 μg).  相似文献   

19.
Transgenic Bt cotton expressing Cry1Ac is important in controlling various agricultural pests, including Helicoverpa armigera. Especially for transgenic crops that are cultivated in large expanses, avoiding resistance development is a key for ensuring sustainability of Bt technologies. Integrated pest management, in which transgenic crops are strategically combined with rational pesticide use, may help to prevent H. armigera resistance acquisition in Bt cotton. In this study, we evaluated the toxicity of a novel insecticide (chlorantraniliprole) on Cry1Ac-susceptible and resistant individuals of H. armigera. More specifically, we assessed the effect of chlorantraniliprole on the activity of two enzymes and conducted laboratory bioassays to determine its toxicity on H. armigera larvae. Chlorantraniliprole increased esterase and glutathione-S-transferase activities in Cry1Ac susceptible and resistant populations of H. armigera. Cry1Ac resistant populations XJ-F (Cry1Ac resistance ratio 21.8-fold), XJ-10.0 (95.8-fold) and BTR (3536.5-fold) did not show cross-resistance to chlorantraniliprole, with LC50 values of 0.0733 (μg/mL) in XJ-F, 0.0545 (μg/ml) in XJ-10.0 and 0.0731 (μg/mL) in BTR, which were close to that in the susceptible strain 96S (0.0954 μg/mL). Our work shows that chlorantraniliprole could be considered to be integrated in Bt cotton management schemes to delay the H. armigera resistance development.  相似文献   

20.
A field population of the rice stem borer (Chilo suppressalis Walker) with 203.3-fold resistance to triazophos was collected. After 8-generation of continuous selection with triazophos in laboratory, resistance increased to 787.2-fold, and at the same time, the resistance to isocarbophos and methamidophos was also enhanced by 1.9- and 1.4-fold, respectively, implying some cross-resistance between triazophos and these two organophosphate insecticides. Resistance to abamectin was slightly enhanced by triazophos selection, and fipronil and methomyl decreased. Synergism experiments in vivo with TPP, PBO, and DEM were performed to gain a potential indication of roles of detoxicating enzymes in triazophos resistance. The synergism results revealed that TPP (SR, 1.92) and PBO (SR 1.63) had significant synergistic effects on triazophos in resistant rice borers. While DEM (SR 0.83) showed no effects. Assays of enzyme activity in vitro demonstrated that the resistant strain had higher activity of esterase and microsomal O-demethylase than the susceptible strain (1.20- and 1.30-fold, respectively). For glutathione S-transferase activity, no difference was found between the resistant and the susceptible strain when DCNB was used as substrate. However, 1.28-fold higher activity was observed in the resistant strain when CDNB was used. These results showed that esterase and microsomal-O-demethylase play some roles in the resistance. Some iso-enzyme of glutathione S-transferase may involve in the resistance to other insecticides, for this resistant strain was selected from a field population with multiple resistance background. Acetylcholinesterase as the triazophos target was also compared. The results revealed significant differences between the resistant and susceptible strain. The Vmax and Km of the enzyme in resistant strain was only 32 and 65% that in the susceptible strain, respectively. Inhibition tests in vitro showed that I50 of triazophos on AChE of the resistant strain was 2.52-fold higher. Therefore, insensitive AChE may also involved in triazophos resistance mechanism of rice stem borer.  相似文献   

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