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1.
The resistance levels to alpha-cypermethrin, bifenthrin, pirimiphos-methyl, endosulfan and imidacloprid were determined in Bemisia tabaci (Gennadius) from Crete. Five B tabaci populations collected from greenhouse and outdoor crops were bioassayed and compared with a reference susceptible strain. Bemisia tabaci collected in a floriculture greenhouse exhibited the highest resistance against all insecticides: at LC50, resistance factors were 23-fold for bifenthrin, 80-fold for alpha-cypermethrin, 18-fold for pirimiphos-methyl, 58-fold for endosulfan and 730-fold for imidacloprid. A population collected on outdoor melons was more susceptible than the reference strain against all insecticides tested, suggesting the occurrence of local highly susceptible B tabaci populations in 'refugia'. In pairwise comparisons of resistance levels, correlation was observed between the LC50 values of the pyrethroid insecticides bifenthrin and alpha-cypermethrin.  相似文献   

2.
Three collections of Bemisia tabaci were taken from cotton and vegetable crops at the beginning of the growing season in Egypt. These displayed marked resistance to the carbamates carbosulfan (ca 20- to 50-fold) and aldicarb (ca 40- to 80-fold) and moderate resistance to the pyrethroids cypermethrin (ca 10- to 30-fold) and lambda-cyhalothrin (ca 10- to 25-fold). They displayed no resistance to the organophosphates profenofos and pirimiphos-methyl, or to imidacloprid. Another population, collected at the end of the growing season, differed markedly in its response. In this population, resistance to carbosulfan remained high (ca 40-fold), resistance to profenofos and cypermethrin was increased (ca 20- and 50-fold respectively) and a slight resistance to imidacloprid was detected (ca 6-fold). Resistance to cypermethrin and profenofos was shown to be similar among adults and nymphs. Irrespective of collection date, none of the populations showed resistance to pyriproxyfen. These Egyptian populations were compared with two representative Israeli populations. The differences between their resistance profiles is discussed in terms of their collection date, their geographical proximity and the patterns of insecticide use at their sites of collection.  相似文献   

3.
BACKGROUND: Bemisia tabaci (Gennadius) biotype B is one of the most important pests on cotton around the world. Laboratory, greenhouse and field experiments were conducted to determine the efficacy of thiamethoxam and imidacloprid seed treatments against B. tabaci on cotton. RESULTS: Under laboratory conditions, the two treatments caused whitefly adult mortality, reduced oviposition and increased mortality of nymphs at 10, 20, 30 and 40 days after germination (DAG). The longer the adults fed on plants from treated seeds, the higher the mortality. The two treatments did not have any effect on eggs. The efficacy of the treated seeds against B. tabaci gradually decreased from 10 to 40 DAG, being the lowest at 40 DAG. In laboratory experiments, the efficacies between the two treatments were similar. In greenhouse experiments, the two treatments were equally effective with lower numbers of whiteflies than untreated controls. With both treatments the concentrations of the active ingredient were gradually reduced with aging of the plants and from the bottom to the top leaves of the plants. Numbers of live whiteflies were well correlated with the dosage of active ingredients. Under field conditions, the seeds treated with both insecticides exhibited similar efficacy against B. tabaci for up to ~2 months. CONCLUSION: Cotton seeds treated with imidacloprid and thiamethoxam were effective against B. tabaci for up to 45 days under laboratory and greenhouse conditions, and up to ~2 months under field conditions. Use of imidacloprid‐ and thiamethoxam‐treated seeds can be an important alternative for management of whiteflies on cotton. Copyright © 2010 Society of Chemical Industry  相似文献   

4.
Pyriproxyfen, a juvenile hormone (JH) mimic, is a biorational insecticide that disrupts insect development. It is one of the principal insecticides being used to control Bemisia tabaci (Gennadius) on cotton, and has many environmentally positive attributes that make it compatible with integrated pest management (IPM) programs. In Israel, a high level of resistance to pyriproxyfen has been observed in several isolated regions. Here, tests were conducted to establish whether temporal refuges from exposure to pyriproxyfen could be useful for restoring the effectiveness of the compound. Resistance was found to decrease by a factor of 8 when exposure to pyriproxyfen was ceased for 13 generations. Reversal of resistance was accompanied with increased biotic fitness of the revertant colony. By incorporating experimental estimates of nymph survival, sex ratio, fecundity, egg hatching rate and developmental time, the seasonal cost per generation for resistant insects was estimated to be 25%. A genetic simulation model, optimized by empirical data from bioassays, predicted fitness cost per generation of 19% for resistant homozygous (RR) females and hemizygous (R) males, and produced rates of reversal similar to the experimental results. The model also predicted that, even after 5 years ( approximately 55 generations) without pyriproxyfen treatments, the frequency of the resistance allele (R) will still remain high (0.02). It is therefore concluded, on the basis of experimental and modeling results, that the effectiveness of temporal refuges for reversing development of resistance to pyriproxyfen in B. tabaci may be limited.  相似文献   

5.
Research was conducted in 14 cotton fields (3-10 ha) selected in seven localities (two fields per locality) in Burkina Faso, with the objectives of: (1) estimating Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) population abundance, (2) assessing the levels of parasitism by Encarsia spp and Eretmocerus spp (Hymenoptera: Aphelinidae) and (3) estimating the susceptibilities of the pest and of an Eretmocerus sp to the insecticides currently sprayed on cotton. Yellow sticky cards and a leaf-turning technique were used to estimate adult B. tabaci population densities. Yellow sticky cards were also used to estimate the densities of adult Eretmocerus sp and the susceptibilities of B. tabaci to insecticides. Leaf disk techniques were used to estimate B. tabaci red eye nymph populations and parasitism by Encarsia spp and Eretmoceus spp was evaluated using stereo-microscopy. A leaf cage technique was used to estimate the susceptibilities of Eretmocerus sp to insecticides. A mean of 6.5-27.4 adult B. tabaci were trapped per yellow sticky card and 5.5 to > 34.9 were counted per leaf using the leaf turning technique. There were 0.14-13 Eretmocerus sp trapped per yellow sticky card. The levels of parasitism varied between 36 and 87% by the end of the season and parasitism by Eretmocerus sp predominated in most of the fields. The susceptibilities of B. tabaci and Eretmocerus sp varied from field to field and with the insecticide tested.  相似文献   

6.
BACKGROUND: B‐biotype Bemisia tabaci (Gennadius) has invaded China over the past two decades. To understand the risks and to determine possible mechanisms of resistance to thiamethoxam in B. tabaci, a resistant strain was selected in the laboratory. Cross‐resistance and the biochemical mechanisms of thiamethoxam resistance were investigated in the present study. RESULTS: A 66.3‐fold thiamethoxam‐resistant B. tabaci strain (TH‐R) was established after selection for 36 generations. Compared with the susceptible strain (TH‐S), the selected TH‐R strain showed obvious cross‐resistance to imidacloprid (47.3‐fold), acetamiprid (35.8‐fold), nitenpyram (9.99‐fold), abamectin (5.33‐fold) and carbosulfan (4.43‐fold). No cross‐resistance to fipronil, chlorpyrifos or deltamethrin was seen. Piperonyl butoxide (PBO) and triphenyl phosphate (TPP) exhibited significant synergism on thiamethoxam effects in the TH‐R strain (3.14‐ and 2.37‐fold respectively). However, diethyl maleate (DEM) did not act synergistically with thiamethoxam. Biochemical assays showed that cytochrome P450 monooxygenase activities increased 1.21‐ and 1.68‐fold respectively, and carboxylesterase activity increased 2.96‐fold in the TH‐R strain. However, no difference was observed for glutathione S‐transferase between the two strains. CONCLUSION: B‐biotype B. tabaci develops resistance to thiamethoxam. Cytochrome P450 monooxygenase and carboxylesterase appear to be responsible for the resistance. Reasonable resistance management that avoids the use of cross‐resistance insecticides may delay the development of resistance to thiamethoxam in this species. Copyright © 2009 Society of Chemical Industry  相似文献   

7.
分别采用浸卵法、浸渍法和浸叶法测定了22、25、28、31和34℃下吡虫啉对B型烟粉虱Bemisia tabaci B-biotype不同虫态的控制效果。结果表明,随着温度的升高,吡虫啉对B型烟粉虱不同虫态的控制效果也逐渐上升,当温度上升至34℃时,60mg/L浓度药液处理下卵、低龄若虫、高龄若虫及成虫死亡率分别较22℃时升高了20.89%、33.52%、33.37%及17.86%。因此,温度提高对吡虫啉防治B型烟粉虱起到了正面效应。  相似文献   

8.
BACKGROUND: The presence of certain symbiotic microorganisms may be associated with insecticide resistance in insects. The authors compared the susceptibility of two isofemale lines, Rickettsia-plus and Rickettsia-free, of the sweet potato whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) to major insecticides from different chemical groups, including imidacloprid, acetamiprid, thiamethoxam, pyriproxyfen, spiromesifen and diafenthiuron. RESULTS: While the Rickettsia-plus and Rickettsia-free lines showed no differences in their susceptibility to imidacloprid and diafenthiuron, higher susceptibility of the Rickettsia-plus line to acetamiprid, thiamethoxam, spiromesifen and especially pyriproxyfen was observed. LC(90) values indicated that the Rickettsia-free line was 15-fold more resistant to pyriproxyfen than the Rickettsia-plus line. CONCLUSION: Findings indicate that the infection status of B. tabaci populations by Rickettsia is an important consideration that should be taken into account when performing resistance monitoring studies, and may help in understanding the dynamics of B. tabaci resistance, symbiont-pest associations in agricultural systems and the biological impact of Rickettsia on whitefly biology.  相似文献   

9.
Resistance to three organophosphate and four pyrethroid insecticides was monitored from 1992 to 2000 in field populations of adult whiteflies, Bemisia tabaci, from Pakistan using a leaf-dip method. There was generally a very high resistance to dimethoate and deltamethrin, and a moderate resistance to monocrotophos during 1992 to 1996. From 1997 to 2000, resistance to these insecticides dropped to low levels because of less reliance on them for whitefly control, and introduction of new chemistries with novel modes of action that had no cross-resistance to conventional insecticides. Concurrently, whitefly resistance to acephate, fenpropathrin, lambda-cyhalothrin and bifenthrin mostly remained low. An insecticide resistance management strategy is recommended that particularly emphasizes the rotation of still-effective insecticides from different chemical classes along with the use of novel chemicals and other tactics of integrated pest management.  相似文献   

10.
BACKGROUND: Resistance to numerous insecticide classes in Bemisia tabaci Gennadius has impaired field control efficacy in south‐eastern China. The biotype and resistance status of B. tabaci collected from these areas was investigated. RESULTS: Two different biotypes of B. tabaci (B‐biotype and Q‐biotype) were detected in south‐eastern China, and the samples collected from geographical regions showed a prevalence of the Q‐biotype and the coexistence of B‐ and Q‐biotypes in some regions. Moderate to high levels of resistance to two neonicotinoids were established in both biotypes (28–1900‐fold to imidacloprid, 29–1200‐fold to thiamethoxam). Medium to high levels of resistance to alpha‐cypermethrin (22–610‐fold) were also detected in both biotypes. Four out of 12 populations had low to medium levels of resistance to fipronil (10–25‐fold). Four out of 12 populations showed low levels of resistance to spinosad (5.7–6.4‐fold). All populations tested were susceptible to abamectin. CONCLUSION: The Q‐biotype B. tabaci is supplanting the B‐biotype which used to be ubiquitous in China. Field populations of both B‐ and Q‐biotypes of B. tabaci have developed high levels of resistance to imidacloprid and thiamethoxam. Abamectin is the most effective insecticide against adult B. tabaci from all populations. Copyright © 2010 Society of Chemical Industry  相似文献   

11.
采用浸叶法分别测定了宁夏8个地区烟粉虱成虫田间种群对4类5种杀虫剂的抗性.结果 表明,供试烟粉虱种群对高效氯氰菊酯已产生了中等至极高水平抗性,抗性倍数为33.31~227.98倍;对烯啶虫胺产生了中等至高水平抗性,抗性倍数为12.14~69.33倍;对毒死蜱和吡虫啉产生了低至中等水平抗性,抗性倍数分别为7.63~38....  相似文献   

12.
利用“Y”型嗅觉仪测定了14种植物挥发物对烟粉虱成虫Bemisia tataci EMD隐种的作用。结果表明,10%的1,8-桉树脑、丁香酚、月桂烯、苎烯和肉桂醛引诱作用较强,其中1,8-桉树脑和月桂烯效果最好(P<0.001)。而顺-3-已烯-醇蒎烯和戊烯为趋避作用,其中顺-3-已烯-醇蒎烯趋避性最强;1%的1,8-桉树脑、丁香酚、月桂烯、烟酸乙酯和橙花醇引诱作用显著,其中1,8-桉树脑和丁香酚的效果最好(P<0.01)。顺-3-已烯-醇蒎烯和戊烯为趋避作用,二者之间无显著差异;将有引诱作用的单体复配后,仅1,8-桉树脑+丁香酚(1:1)和1,8-桉树脑+月桂烯(1:1)有引诱作用;10%的1,8-桉树脑涂抹黄板显著提高了黄板诱杀力。因此,植物挥发物对烟粉虱有趋避或引诱作用,其作用因浓度而发生改变,趋性一致的复配后不一定能发挥原有作用。  相似文献   

13.
Pyriproxyfen is a biorational insecticide that acts as a juvenile hormone (JH) analogue and disrupts insect development with an unknown molecular mode of action. Pyriproxyfen is one of the major insecticides used to control the whitefly Bemisia tabaci (Gennadius) and comply with integrated pest management (IPM) programmes, resulting in minimal effects on the environment, humans and beneficial organisms. During the last few years, resistance to pyriproxyfen has been observed in several locations in Israel, sometimes reaching a thousandfold or more. No information exists about the molecular basis underlying this resistance that may lead to understanding the mode of action of pyriproxyfen and developing molecular markers for rapid monitoring of resistance outbreaks. In this communication, a cDNA microarray from B. tabaci was used to monitor changes in gene expression in a resistant B. tabaci population. Based on statistical analysis, 111 expressed sequence tags (ESTs) were identified that were differentially upregulated in the resistant strain after pyriproxyfen treatment. Many of the upregulated ESTs observed in the present study belong to families usually associated with resistance and xenobiotic detoxification such as mitochondrial genes, P450s and oxidative stress, genes associated with protein, lipid and carbohydrate metabolism and others related to JH-associated processes in insects such as oocyte and egg development.  相似文献   

14.
BACKGROUND: Spiromesifen is a novel insecticidal/acaricidal compound derived from spirocyclic tetronic acids that acts effectively against whiteflies and mites via inhibition of acetyl‐CoA‐carboxylase, a lipid metabolism enzyme. The effects of spiromesifen on the developmental stages of the whitefly Bemisia tabaci (Gennadius) were studied under laboratory conditions to generate baseline action thresholds for field evaluations of the compound. RESULTS: Adult B. tabaci mortality rate after spiromesifen treatment (5 mg L?1) was 40%. Treatment with 0.5 mg L?1 reduced fecundity per female by more than 80%, and fertility was almost nil. LC50 for eggs was 2.6 mg L?1, and for first instar 0.5 mg L?1. Scanning electron microscopy revealed that eggs laid by treated adult females had an abnormally perforated chorion, and females were unable to complete oviposition. Light and fluorescent microscopy showed significantly smaller eggs following treatment, and smaller, abnormally formed and improperly localized bacteriomes in eggs and nymphs. The number of ovarioles counted in females treated with 5 mg L?1 was significantly reduced. Spiromesifen showed no cross‐resistance with other commonly used insecticides from different chemical groups, and resistance monitoring in Israel showed no development of field resistance to this insecticide after 1 year of use. CONCLUSION: The strong effect on juvenile stages of B. tabaci with a unique mode of action and the absence of cross‐resistance with major commonly used insecticides from different chemical groups suggest the use of spiromesifen in pest and resistance management programmes. Copyright © 2008 Society of Chemical Industry  相似文献   

15.
为了明确北京地区蔬菜烟粉虱的种群发展动态及对常用烟碱类杀虫剂的抗药性,为烟粉虱防治适期的确定及高效杀虫剂的选择提供基础资料及科学指导,2009年调查了北京地区春茬和秋茬蔬菜烟粉虱的种群动态,并监测了该地区2009-2011年度烟粉虱种群对3种烟碱类杀虫剂的抗药性。结果表明,春茬蔬菜烟粉虱在5月中旬种群快速上升,持续到春茬拉秧;秋茬蔬菜烟粉虱在塑料棚内9月上旬种群数量即开始上升,露地出现时间较晚,10月中旬后种群数量下降;塑料棚内种群数量明显高于露地蔬菜烟粉虱数量。烟粉虱2009年对吡虫啉和噻虫嗪的抗药性很高,2010年和2011年抗性程度显著下降,LC50处于133.94~251.16mg/L,属中等抗性水平;而对新型杀虫剂烯啶虫胺的抗药性在近3年内持续升高,抗性倍数由6.68倍升至83.62倍,即由低抗性水平升至高抗性水平。上述调查结果表明,北京地区蔬菜烟粉虱的防治应掌握春季5月中旬前、秋季9月中旬前种群处于低密度时进行。烟粉虱对新型杀虫剂烯啶虫胺的抗药性在近三年内快速上升,生产中应注意药剂的轮换使用。  相似文献   

16.
BACKGROUND: A major problem of crop protection in Crete, Greece, is the control of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) with chemical insecticides owing to the rapid development of resistance. The aim of this study was to investigate the establishment of resistance and the underlying mechanisms to major insecticide classes with classical bioassays and known biochemical resistance markers. RESULTS: During a 2005–2007 survey, 53 Q biotype populations were collected. Application history records showed extensive use of neonicotinoids, organophosphates, carbamates and pyrethroids. High resistance levels were identified in the majority of populations (>80%) for imidacloprid (RF: 38–1958×) and α‐cypermethrin (RF: 30–600×). Low resistance levels (RF < 12) were observed for pirimiphos‐methyl. A strong correlation between resistance to imidacloprid and the number of applications with neonicotinoids was observed. Significant correlations were observed between COE and P450‐dependent monoxygenase activity with resistance to α‐cypermethrin and imidacloprid respectively. A propoxur‐based AChE diagnostic test indicated that iAChE was widespread in most populations. Resistance levels for α‐cypermethrin were increased when compared with a previous survey (2002–2003). Differentiation of LC50 values between localities was observed for imidacloprid only. CONCLUSION: Bemisia tabaci resistance evolved differently in each of the three insecticides studied. Imidacloprid resistance seems less established and less persistent than α‐cypermethrin resistance. The low resistance levels for pirimiphos‐methyl suggest absence of cross‐resistance with other organophosphates or carbamates used. Copyright © 2008 Society of Chemical Industry  相似文献   

17.
BACKGROUND: The presence of symbiotic microorganisms may influence an insect's ability to tolerate natural and artificial stress agents such as insecticides. The authors have previously shown that Rickettsia in the B biotype of the whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) increases this insect's susceptibility to several insecticidal compounds. This communication reports a comparison of the susceptibilities of three isofemale strains of the Q biotype of B. tabaci harbouring different bacterial complements to major insecticides from different chemical groups: one strain harboured only Arsenophonus, one harboured Rickettsia and Arsenophonus and one harboured Arsenophonus and Wolbachia. RESULTS: The presence of different symbiont combinations in the three strains had a significant influence on their susceptibility to most of the insecticides tested. Thiamethoxam, imidacloprid, pyriproxyfen and spiromesifen had a significant influence on strains that had the double infections RickettsiaArsenophonus and Wolbachia–Arsenophonus, which also carried higher amounts of symbionts as assessed by quantitative real‐time PCR. No significant differences in mortality rates were observed when the tested strains were treated with diafenthiuron. CONCLUSION: The results suggest a correlation between the presence of high bacterial densities in B. tabaci and the insect's ability to detoxify toxic compounds such as insecticides. Copyright © 2009 Society of Chemical Industry  相似文献   

18.
Separation of non‐specific esterases on electrophoretic gels has played a key role in distinguishing between races or biotypes of the tobacco whitefly, Bemisia tabaci. One intensively staining esterase in particular (termed E0.14) has assumed significance as a diagnostic of B‐type whiteflies (aka Bemisia argentifolii), despite any knowledge of its biological function. In this study, a whitefly strain (B‐Null) homozygous for a null allele at the E0.14 locus that had been isolated from a B‐type population was used to demonstrate a significant role for E0.14 in resistance of B‐type populations to pyrethroids but not to organophosphates (OPs). Bioassays with pyrethroids, following pre‐treatment with sub‐lethal doses of the OP profenofos (to inhibit esterase activity), coupled with metabolism studies with radiolabelled permethrin, supported the conclusion that pyrethroid resistance in a range of B‐type strains expressing E0.14 was primarily due to increased ester hydrolysis. In the same strains, OP resistance appeared to be predominantly conferred by a modification to the target‐site enzyme acetylcholinesterase. © 2000 Society of Chemical Industry  相似文献   

19.
Xie W  Wang S  Wu Q  Feng Y  Pan H  Jiao X  Zhou L  Yang X  Fu W  Teng H  Xu B  Zhang Y 《Pest management science》2011,67(1):87-93
BACKGROUND: The polyphagous B‐biotype Bemisia tabaci (Gennadius) has developed a high resistance to commonly used insecticides in China. To illustrate the induced changes by host plant, bioassay and biochemical research on five different host populations were investigated. RESULTS: Except for bifenthrin, all tested insecticides showed lower toxicity to the B. tabaci poinsettia population compared with other host populations. Moreover, four insecticides, the exceptions being abamectin and fipronil, showed highest toxicity towards the tomato population. The LC50 values of the poinsettia population, particularly towards acetamiprid, were 14.8‐, 10.3‐ and 7.29‐fold higher than those of tomato, cucumber and cabbage respectively. The CarE activities of B. tabaci cabbage and cucumber populations were all significantly higher than those of poinsettia, cotton and tomato populations. The ratio of the cabbage population was 1.97‐, 1.79‐ and 1.30‐fold higher than that of poinsettia, cotton and tomato respectively. The frequency profiles for this activity also have obvious differences. The GST and P450 activities of the cucumber population were the lowest in the five host populations. CONCLUSION: Long‐term induction of host plants for B‐biotype B. tabaci could influence their susceptibilities to several insecticides. Rational selection and usage of insecticides for particular hosts will be helpful for resistance management and control of this species. Copyright © 2010 Society of Chemical Industry  相似文献   

20.
Q型烟粉虱对不同烟草品种及其挥发物的行为反应   总被引:1,自引:0,他引:1  
为明确烟草不同品种对Q型烟粉虱[Bemisia tabaci(Gennadius)]抗性水平的差异,在(25±1)℃、RH=80%、L∥D=16h∥8h条件下,研究了Q型烟粉虱成虫对20个烟草品种的取食和产卵选择性。结果表明,接虫72h,‘YY203’和‘K326’两个烟草品种的成虫数和产卵量最少,平均每株有成虫分别为8.25、9.25头,卵分别为31.50、40.75粒,但两个品种间成虫数和产卵量差异均不显著;‘CF226’品种的成虫数和产卵量最多,平均每株有成虫41.25头,卵406.48粒。进一步利用Y形嗅觉仪,测定了Q型烟粉虱对3个品种(‘YY203’、‘K326’和‘CF226’)烟草叶片气味及其提取物的嗅觉行为反应,结果表明,‘CF226’叶片及相应的挥发物提取物对烟粉虱成虫均具有显著的引诱作用,而‘YY203’和‘K326’叶片和挥发物提取物的引诱作用均不明显;Q型烟粉虱成虫对烟草挥发物提取物的趋向性比单纯的寄主植物叶片的趋向性强,但总的反应趋势相似。‘YY203’和‘K326’两个品种烟草对Q型烟粉虱有明显抗性。  相似文献   

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