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1.
BACKGROUND: The insect growth regulator pyriproxyfen has provided effective control of the whitefly Bemisia tabaci Gennadius in many countries. Here, whether or not fitness costs were associated with pyriproxyfen resistance in a laboratory‐selected resistant strain (QC02‐R) of the B biotype was determined. RESULTS: Mortality caused by pyriproxyfen and fitness traits over time were measured in unselected and selected hybrid strains, which were created by crossing individuals of the resistant strain with individuals of a susceptible strain. Fitness costs were not associated with resistance in QC02‐R, as mortality caused by pyriproxyfen did not increase over time in unselected hybrid strains and fitness traits were similar in unselected and selected hybrid strains. Using a new method to examine the inheritance of resistance, based on data from fitness cost experiments, it was estimated that pyriproxyfen resistance is controlled by two loci in the QC02‐R strain. CONCLUSION: The lack of fitness costs associated with pyriproxyfen resistance could promote the evolution of resistance in field populations with similar traits to QC02‐R. Copyright © 2008 Society of Chemical Industry  相似文献   

2.
The toxicities of eight structurally different acaricidal compounds to six‐legged larvae (first motile stage) of three laboratory strains of the two‐spotted spider mite, Tetranychus urticae, and the European red mite, Panonychus ulmi, were evaluated following spray application. The larvae of five field‐derived strains of T urticae originating from France, Italy, Brazil, California and Florida were also tested for their susceptibilities to discriminating concentrations of several acaricides resulting in 95% mortality when applied to the organophosphate‐resistant laboratory reference strain WI. The spray bioassay used was robust and gave repeatable results with a wide range of acaricidal compounds, irrespective of their mode of action (ovo‐larvicides or primarily acting on motile life stages). Compounds tested were abamectin, azocyclotin, chlorpyrifos, clofentezine, deltamethrin, fenpyroximate, hexythiazox and pyridaben. Larvae of one of the laboratory strains of T urticae, AK, originally collected in Japan in 1996 and maintained without further selection pressure, exhibited 2000‐ and >4000‐fold resistance to the mitochondrial electron transport inhibitors pyridaben and fenpyroximate, respectively. Another strain of T urticae, AU, obtained from Australia and maintained in the laboratory under selection with hexythiazox and clofentezine since 1987 showed >770‐ and >1000‐fold resistance to clofentezine and hexythiazox, respectively. The same resistance pattern was observed against larvae of a laboratory strain of P ulmi, CE, also selected with hexythiazox. Larvae of one of the field‐derived strains of T urticae, BR, showed a lower susceptibility to a number of compounds, whilst the others were susceptible to all compounds except the organophosphates. © 2001 Society of Chemical Industry  相似文献   

3.

BACKGROUND

Tebufenozide is widely used to control populations of the smaller tea tortrix, Adoxophyes honmai. However, A. honmai has evolved resistance such that straightforward pesticide application is an untenable long-term approach for population control. Evaluating the fitness cost of resistance is key to devising a management strategy that slows the evolution of resistance.

RESULTS

We used three approaches to assess the life-history cost of tebufenozide resistance with two strains of A. honmai: a tebufenozide-resistant strain recently collected from the field in Japan and a susceptible strain that has been maintained in the laboratory for decades. First, we found that the resistant strain with standing genetic variation did not decline in resistance in the absence of insecticide over four generations. Second, we found that genetic lines that spanned a range of resistance profiles did not show a negative correlation between their LD50, the dosage at which 50 % of individuals died, and life-history traits that are correlates of fitness. Third, we found that the resistant strain did not manifest life-history costs under food limitation. Our crossing experiments indicate that the allele at an ecdysone receptor locus known to confer resistance explained much of the variance in resistance profiles across genetic lines.

CONCLUSION

Our results indicate that the point mutation in the ecdysone receptor, which is widespread in tea plantations in Japan, does not carry a fitness cost in the tested laboratory conditions. The absence of a cost of resistance and the mode of inheritance have implications for which strategies may be effective in future resistance management efforts. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

4.
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   

5.
Han J  Kim SI  Choi BR  Lee SG  Ahn YJ 《Pest management science》2011,67(12):1583-1588
BACKGROUND: This study was aimed at assessing the fumigant toxicity of 14 essential oil constituents from lemon eucalyptus, Eucalyptus citriodora Hook, and another ten known compounds to females of acaricide‐susceptible, chlorfenapyr‐resistant, fenpropathrin‐resistant, pyridaben‐resistant and abamectin‐resistant strains of Tetranychus urticae Koch. RESULTS: Menthol (LC50, 12.9 µg cm?3) was the most toxic compound, followed by citronellyl acetate (16.8 µg cm?3), against the susceptible females. High toxicity was also produced by β‐citronellol, citral, geranyl acetate and eugenol (LC50, 21.7–24.6 µg cm?3). The fumigant toxicity of these compounds was almost identical against females from either of the susceptible and resistant strains, indicating that the compounds and acaricides do not share a common mode of action or elicit cross‐resistance. CONCLUSION: Global efforts to reduce the level of highly toxic synthetic acaricides in the agricultural environment justify further studies on materials derived from lemon eucalyptus oil, particularly menthol and citronellyl acetate, as potential acaricides for the control of acaricide‐resistant T. urticae as fumigants with contact action. Copyright © 2011 Society of Chemical Industry  相似文献   

6.
二斑叶螨对阿维菌素的抗药性及抗性基因的PASA检测技术   总被引：2，自引：1，他引：1  
为了明确二斑叶螨Tetranychus urticae Koch对阿维菌素的抗性水平,采用玻片浸渍法测定了北京4个地区二斑叶螨雌成螨对阿维菌素的抗药性,建立了特异性等位基因PCR（PASA）方法,并检测了二斑叶螨谷氨酸门控氯离子通道（GluCl）基因片段上G323D的突变频率。结果显示,北京昌平、海淀、密云和怀柔4个田间二斑叶螨种群对阿维菌素均达极高抗性水平,其中昌平种群抗性最高,LC50值为448.93 mg/L,抗性倍数为4 988.11倍。室内敏感种群未见抗性个体,昌平和密云种群G323D等位基因突变频率为100.00%,怀柔和海淀种群分别为86.25%和90.00%。北京4个地区二斑叶螨种群对阿维菌素达极高抗性水平,抗性基因的突变频率也很高,表明阿维菌素不适宜用来防治这些地区的二斑叶螨种群。  相似文献   

7.
A susceptible strain of diamondback moth, Plutella xylostella (L.), was used to select for resistance to tebufenozide in the laboratory. After continuous selection with tebufenozide 17 times during 35 generations, a resistant strain was achieved with high resistance to tebufenozide (RR 93.8). Bioassay revealed that this strain showed high cross-resistance to abamectin (RR 35.7), methoxyfenozide (29.1) and JS118 (16.5), and a little to deltamethrin (3.9), but no obvious cross-resistance was found to cypermethrin (1.3), fipronil (1.3), trichlorfon (1.1), chlorfenapyr (1.0), phoxim (0.9) and acephate (0.8). The resistant and susceptible insects had similar development rates, but life table tests indicated that the resistant strain showed reproductive disadvantages, including decreased copulation rate, reproductivity and hatchability. When compared with the susceptible strain, the resistant insects had a relative fitness of only 0.3. This indicated that tebufenozide resistance selected under laboratory conditions had considerable fitness costs in this pest, and therefore rotational use of insecticides without cross-resistance is recommended to delay development of resistance.  相似文献   

8.
Nine different strains of the two-spotted spider miteTetranychus urticae Koch (Acari: Tetranychidae) were collected on cotton from Adana, Antalya, Izmir, Manisa and Urfa in Turkey. Their responses to bifenthrin were investigated using conventional bioassay and biochemical assays. LC50 and LC90 values of bifenthrin were determined for all strains by using a residual bioassay with a petri dish-spray tower. Resistance ratios were determined by comparing the samples with a standard susceptible strain, GSS. The resistance ratios of the strains ranged from <1 to 669-fold (at LC50). Of the investigated field strains, only three (two from Adana and one from Urfa) were resistant to bifenthrin. There was a correlation between esterase enzyme activity and bifenthrin resistance according to polyacrylamide gel electrophoresis and microtiter plate assays in the three resistant strains. http://www.phytoparasitica.org posting May 17, 2005.  相似文献   

9.
Glutathione S-transferases (GSTs) are known to catalyze conjugations by facilitating the nucleophilic attack of the sulfhydryl group of endogenous reduced glutathione on electrophilic centers of a vast range of xenobiotic compounds, including insecticides and acaricides. Elevated levels of GSTs in the two-spotted spider mite, Tetranychus urticae Koch, have recently been associated with resistance to acaricides such as abamectin [Pestic. Biochem. Physiol. 72 (2002) 111]. GSTs from acaricide susceptible and resistant strains of T. urticae were purified by glutathione-agarose affinity chromatography and characterized by their Michaelis-Menten kinetics towards artificial substrates, i.e., 1-chloro-2,4-dinitrobenzene and monochlorobimane. The inhibitory potential of azocyclotin, dicumarol, and plumbagin was low (IC50 values > 100 μM), whereas ethacrynic acid was much more effective, exhibiting an IC50 value of 4.5 μM. GST activity is highest in 2-4-day-old female adults and dropped considerably with progressing age. Furthermore, molecular characteristics were determined for the first time of a GST from T. urticae, such as molecular weight (SDS-PAGE) and N-terminal amino acid sequencing (Edman degradation). Glutathione-agarose affinity purified GST from T. urticae strain WI has a molecular weight of 22.1 kDa. N-terminal amino acid sequencing revealed a homogeneity of ≈50% to insect GSTs closely related to insect class I GSTs (similar to mammalian Delta class GSTs).  相似文献   

10.
BACKROUND: In Tetranychus urticae Koch, acetylcholinesterase insensitivity is often involved in organophosphate (OP) and carbamate (CARB) resistance. By combining toxicological, biochemical and molecular data from three reference laboratory and three OP selected strains (OP strains), the AChE1 mutations associated with resistance in T. urticae were characterised. RESULTS: The resistance ratios of the OP strains varied from 9 to 43 for pirimiphos‐methyl, from 78 to 586 for chlorpyrifos, from 8 to 333 for methomyl and from 137 to 4164 for dimethoate. The insecticide concentration needed to inhibit 50% of the AChE1 activity was, in the OP strains, at least 2.7, 55, 58 and 31 times higher for the OP pirimiphos‐methyl, chlorpyrifos oxon, paraoxon and omethoate respectively, and 87 times higher for the CARB carbaryl. By comparing the AChE1 sequence, four amino acid substitutions were detected in the OP strains: (1) F331W (Torpedo numbering) in all the three OP strains; (2) T280A found in the three OP strains but not in all clones; (3) G328A, found in two OP strains; (4) A201S found in only one OP strain. CONCLUSIONS: Four AChE1 mutations were found in resistant strains of T. urticae, and three of them, F331W, G328A and A201S, are possibly involved in resistance to OP and CARB insecticides. Among them, F331W is probably the most important and the most common in T. urticae. It can be easily detected by the diagnostic PCR‐RLFP assay developed in this study. Copyright © 2009 Society of Chemical Industry  相似文献   

11.
The two-spotted spider mite, Tetranychus urticae Koch, is a key pest of many agricultural crops. Studies of stability of resistance, cross-resistance relationships and monitoring of chlorfenapyr resistance were carried out with T. urticae to provide basic information necessary to define effective acaricide resistance management strategies for this pest. Chlorfenapyr resistance was shown to be stable in the absence of selection pressure under laboratory conditions. The activities of seven different acaricides against chlorfenapyr-resistant and -susceptible strains of T. urticae were evaluated. The results indicated possible positive cross-resistance between chlorfenapyr and the acaricides abamectin, propargite and etoxazole. No cross-resistance was detected for the acaricides milbemectin, fenpyroximate and diafenthiuron. A possible negatively correlated cross-resistance was observed between chlorfenapyr and spiromesifen. The evaluation of 21 T. urticae populations from several crops in the States of São Paulo, Mato Grosso, Goiás, and Bahia, in Brazil, indicated that the susceptibility of mites to chlorfenapyr was variable, with percentages of resistant mites ranging from 0.0 to 86.5%. The highest resistance frequencies were observed in ornamental plants in the State of São Paulo. Some populations from cotton and papaya also presented high frequencies of chlorfenapyr resistance. This is the first report on chlorfenapyr resistance in T. urticae on cotton and papaya in Brazil. Strategies for the management of acaricide resistance are discussed.  相似文献   

12.
Three Australian Sisymbrium orientale and one Brassica tournefortii biotypes are resistant to acetolactate synthase (ALS)-inhibiting herbicides due to their possession of an ALS enzyme with decreased sensitivity to these herbicides. Enzyme kinetic studies revealed no interbiotypic differences within species in Km (pyruvate) (the substrate concentration at which the reaction rate is half maximal) but a greater Vmax (the rate when the enzyme is fully saturated with substrate) for two of the resistant S orientale biotypes over susceptible levels. F1 hybrids from reciprocal crosses between resistant and susceptible biotypes of S orientale showed an intermediate response to chlorsulfuron compared to the parental plants. ALS herbicide resistance in S orientale segregated in a 3:1 (resistant:susceptible) ratio in F2 plants with a single rate of chlorsulfuron, indicating that resistance is inherited as a single, incompletely dominant nuclear gene. Two regions of the ALS structural gene known to vary in ALS-resistant biotypes were amplified and sequenced. Resistant S orientale biotypes NS01 and SS03 contained a single nucleotide substitution in Domain B, predicting a Trp (in susceptible) to Leu (in resistant) amino acid change. Two adjacent nucleotide substitutions (CC T to AT T) predicting a Pro (in susceptible) to Ile (in resistant) change in the primary amino acid sequence were identified in Domain A of resistant S orientale biotype SS01. Likewise, a single nucleotide substitution at the same site in the resistant B tournefortii biotype predicts a Pro (in susceptible) to Ala (in resistant) substitution. No other interbiotypic nucleotide differences predicted amino acid changes in the sequenced regions, suggesting that the amino acid substitutions reported above are responsible for resistance to ALS-inhibiting herbicides in the respective biotypes. © 1999 Society of Chemical Industry  相似文献   

13.
Imidacloprid has been used as a key insecticide for controlling sucking insect pests of cotton, whereas Spodoptera litura also has been indirectly exposed to this insecticide in Pakistan. To evaluate the risk of resistance evolution and to develop a better resistance management strategy, a field collected population was selected with imidacloprid in the laboratory. Thereafter, fitness cost, realized heritability and cross resistance of imidacloprid resistance in S. litura were investigated. After 14 generations of selection with imidacloprid, S. litura developed a 137.48-fold resistance to the insecticide. Bioassay revealed that this strain showed cross-resistance to acetamiprid (RR 8.52) and a little to lamdacyhalothrin (1.92) but negative cross-resistance was found to methomyl (−0.19). The resistant strain had a relative fitness of 0.38, with substantially lower rates of larval survival, larval duration, male pupal duration, development time, emergence rate of healthy adults, fecundity, hatchability, and prolonged larval and pupal duration. Mean relative growth rate of the larvae, intrinsic rate of population increase, and biotic potential was lower for the selected populations. The estimated realized heritability (h2) of imidacloprid resistance was 0.15 in the resistant strain of S. litura. Development of the resistance may cost significant fitness for the resistant population. This study provided valuable information for further understanding the impact of imidacloprid resistance on physiological parameters of S. litura and for facilitating the development of resistance management strategies.  相似文献   

14.
在室内用浸叶法累代筛选,建立了抗氯虫苯甲酰胺的小菜蛾 Plutella xylostella (L.)种群,通过系统观察法研究了敏感及抗性种群的生物学特性。结果表明:小菜蛾以每代30%~ 50%的淘汰率筛选10 代后,其对氯虫苯甲酰胺的抗性达9.09 倍;与敏感种群相比,抗性种群的单雌产卵量下降、雄成虫寿命缩短、幼虫历期延长、幼虫存活率下降、化蛹率降低、蛹重下降、羽化率降低,从而 导致抗性种群的净增殖率下降、种群倍增时间延长、内禀增长率下降、相对适合度变小。表明小菜蛾对氯虫苯甲酰胺的抗性在用药初期发展较为缓慢,抗性种群的生物适合度降低,抗性风险相对较低。  相似文献   

15.
Emamectin benzoate, a semisynthetic bioinsecticide, has been used frequently for the management of lepidopteran pests of cotton worldwide. To assess the resistance risk and design strategy for resistance management, life history traits were established for emamectin benzoate-resistant, unselected and susceptible S. litura strains based on the laboratory observations. Bioassay results showed that the emamectin benzoate-selected strain developed a resistance ratio of 911-fold compared with that of the susceptible strain. The emamectin-selected strain had a relative fitness of 0.37 and lower prepupal and pupal weights, prolonged larval duration and development time, lower fecundity and hatchability compared with the susceptible strain. Mean population growth rates, such as intrinsic rate of population increase and biotic potential, were lower for the emamectin-selected strain compared with the susceptible strain. Development of resistance can cost considerable fitness for the emamectin-selected strain. The present study provided useful information for determining potential management strategies to overcome development of resistance.  相似文献   

16.
小菜蛾抗多杀菌素和敏感品系耐低温能力的比较   总被引：1，自引：2，他引：1       下载免费PDF全文
通过杂交筛选得到小菜蛾对多杀菌素敏感和高抗的纯合子品系，对二个品系在适温和经低温处理后的生长发育特性进行了比较，以探明其抗性是否伴有适合度的变化以及适合度变化与温度的关系。结果发现:高抗品系的卵经6℃低温处理14 d，孵化出的幼虫仅有7.7％正常化蛹，显著低于敏感品系61.4％的正常化蛹率；经6℃低温处理28 d，高抗和敏感品系的卵孵化率分别为27％和75％，二者差异显著；高抗品系的蛹经 5℃低温处理7～14 d后，蛹的 发育历期显著延长，其子代卵的存活力也显著下降。在适温25℃下，抗性和敏感品系之间多项生物学特性均无显著差异或差异很小。这些结果表明，小菜蛾对多杀菌素的抗性伴随有耐低温能力的适合度代价。  相似文献   

17.
为明确棉铃虫Helicoverpa armigera（Hübner）对苏云金芽胞杆菌Bacillus thuringiensis（Bt）Cry1Ac毒蛋白抗性的稳定性及其适合度变化,利用生物测定的方法研究了Cry1Ac抗性品系棉铃虫转到正常饲料饲养后的抗性衰退及再次筛选后抗性的恢复情况,并比较了敏感、抗性和抗性衰退后各品系间的适合度差异。在失去选择压的情况下,高抗品系棉铃虫对Cry1Ac的抗性迅速衰退,经过4代后抗性水平由最初的3626.67倍下降到1436.67倍;到第12代时抗性水平已低于10倍,随后品系保持较稳定的低抗水平;当重新进行抗性再筛选时,其抗性水平可快速恢复,抗性倍数快速回升,5代后恢复到1123.33倍。与敏感品系相比,高抗棉铃虫品系的适合度明显降低,相对适合度仅为0.33,但转到正常饲料连续饲养14代后,棉铃虫适合度明显上升,相对适合度为0.87,主要表现为卵孵化率和幼虫存活率等显著提高。  相似文献   

18.
BACKGROUND: The diamondback moth (DBM), Plutella xylostella (L.), is a cosmopolitan pest of cruciferous crops. Fufenozide, a novel non‐steroidal ecdysone agonist, exhibits good efficacy and plays an increasingly important role in the control of Lepidopterous pests in China. A laboratory strain of DBM was selected for resistance to fufenozide, and the genetic basis of resistance was studied. RESULTS: The resistant strain, selected under laboratory conditions, exhibited a higher level of resistance to fufenozide (302.8‐fold based on LC50s) than the laboratory susceptible strain. Mortality data from the testing of F1 progeny of reciprocal crosses of resistant and susceptible DBM indicated that resistance was autosomal and incompletely recessive with a degree of dominance of ?0.664. Chi‐square analysis from responses of a backcross of crossed F1 progeny and the resistant strain and F2 progeny were highly significant, suggesting that the resistance was probably controlled by more than one gene. The estimated realised heritability (h2) of fufenozide resistance was 0.08, indicating that diamondback moth may have a lower chance of developing resistance to fufenozide than other kinds of insecticide. CONCLUSION: The resistance of DBM to fufenozide might be autosomal and incompletely recessive, and the resistance is probably controlled by more than one gene. These results provide the basic information for pest management programmes. Copyright © 2009 Society of Chemical Industry  相似文献   

19.
Tetranychus urticae Koch (Acari: Tetranychidae) is a major pest of several agricultural crops and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) is an important natural enemy of this pest mite. The objective of the study was to evaluate the effect of spiromesifen on the development and reproduction of T. urticae, and to assess the influence of spiromesifen and other acaricides on the population growth rates of the spider mite and its predator, N. californicus. Toxicity tests with spiromesifen at different life stages of T. urticae indicated that eggs less than 72 h old were more sensitive than other development stages. The oviposition rate of T. urticae was significantly affected by spiromesifen. Experiments on the effects of spiromesifen on the growth rates of T. urticae and N. californicus indicated that spiromesifen is innocuous to the predaceous mite but highly toxic to the spider mite, leading to population suppression in 10 days. Fenpropathrin, acephate and neem oil were not harmful to N. californicus, but were not so efficient as spiromesifen in controlling T. urticae, and had significantly less influence on the population growth rates of the spider mite. Among these three products, only neem oil caused significant reduction in the growth rate of T. urticae. Chlorfenapyr, abamectin, milbemectin and diafenthiuron significantly affected the population growth rates of T. urticae and N. californicus. Spiromesifen was the most promising acaricide for managing the two-spotted spider mite, when used in combination with N. californicus.  相似文献   

20.
Jordan 《Weed Research》1999,39(6):493-505
Fitness costs of the triazine resistance mutation were estimated in experimental populations of Amaranthus hybridus L. from Maryland and Virginia (USA). Estimated costs were attributed directly to effects of the resistance mutation, through comparisons of lines bearing similar nuclear genomes, but either resistant or susceptible cytoplasm. Experimental weed plants were established from seed in the field at a wide range of A. hybridus and crop (maize or soyabean) densities, and experiments were repeated over 3 years. Resistant cytoplasm caused large reductions in several components of fitness, but substantial differences were observed among years in these fitness costs of resistance. For the fitness component of total biomass above-ground biomass production, relative fitnesses of resistant genotypes (resistant/susceptible ratios) ranged between 0.42 and 0.70. Costs of resistance were similar in weeds growing with either maize or soyabean crops. Certain costs of resistance differed between populations: impairment of seedling establishment and early growth by the resistance mutation was evident in the Virginia population, but not in the Maryland population. This functional difference between populations was associated with greater costs of resistance in the Virginia population with respect to mid-season leaf number and total above-ground biomass production; however, only the former population difference in fitness cost was statistically significant.  相似文献   

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