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Resistance against dicofol was investigated in the carmine spider mite, Tetranychus cinnabarinus. Higher resistance levels were detected by leaf residual bioassays than by topical bioassays, both done using a Potter spray tower, in almost all populations of T cinnabarinus examined from Antalya, Turkey. For instance, the resistance level at LC95 was 17.5‐fold in topical bioassays but 58.9‐fold in leaf residual bioassays for the population collected from greenhouses in the Topçular district. There were differences of resistance levels at LC95, ranging between 2.6‐ and 23.9‐fold using topical bioassays and between 5.0‐ and 58.9‐fold in residual bioassays, in populations collected from greenhouses from various districts. Populations from cotton showed lower resistance levels against dicofol than populations from greenhouses. Resistance to dicofol at LC50 as indicated by topical and residual bioassays increased 19.7‐ and 100.7‐fold, respectively, in a colony from the laboratory strain of T cinnabarinus selected with dicofol alone for 16 cycles. However, the dicofol resistance at LC50 increased 19.4‐ and 52.0‐fold in another colony selected in rotation with dicofol and tetradifon for six and eight cycles, respectively. The changes in resistance to dicofol 5 months after the selection ceased were as follows: in the colony selected for dicofol alone, using topical and residual bioassays, the resistance levels at LC50 decreased to 11.7‐ and 99.1‐fold, respectively, and in the colony selected in rotation with dicofol and tetradifon to 10.8‐ and 15.8‐fold, respectively. © 2001 Society of Chemical Industry 相似文献
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Pyrethroids, knockdown resistance and sodium channels 总被引：1，自引：0，他引：1
Soderlund DM 《Pest management science》2008,64(6):610-616
Knockdown resistance to DDT and the pyrethrins was first described in 1951 in the housefly (Musca domestica L.). This trait, which confers reduced neuronal sensitivity to these insecticides, was subsequently shown to confer cross-resistance to all synthetic pyrethroid insecticides that have been examined to date. As a consequence, the worldwide commercial development of pyrethroids as a major insecticide class over the past three decades has required constant awareness that pyrethroid overuse has the potential to reselect this powerful resistance mechanism in populations that previously were resistant to DDT. Demonstration of tight genetic linkage between knockdown resistance and the housefly gene encoding voltage-sensitive sodium channels spurred efforts to identify gene mutations associated with knockdown resistance and understand how these mutations confer a reduction in the sensitivity of the pyrethroid target site. This paper summarizes progress in understanding pyrethroid resistance at the molecular level, with particular emphasis on studies in the housefly. 相似文献
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Newcombe G 《Phytopathology》2005,95(7):779-783
ABSTRACT Nonhost resistance is hypothesized to protect plants in a nonspecific manner. For highly specialized parasites, this hypothesis applies not only to distantly related plants but also to resistant congeners of the host species. Congeners of Populus spp. were hybridized to create two interspecific hybrid poplar pedigrees (i.e., Populus trichocarpa x P. deltoides and P. trichocarpa x P. maximowiczii). The pedigrees were planted in a randomized, replicated "common garden" on Vancouver Island so that they were exposed to parasites of the native P. trichocarpa. Monogenic and oligogenic resistance to two ascomycetous, parasitic fungi (i.e., Venturia inopina and a Taphrina sp.) segregated in a parasite-specific manner in each pedigree. However, these resistance genes were not inherited from the native host, P. trichocarpa. Instead, resistance was inherited from the allopatric, nonhost congeners, P. deltoides (eastern cottonwood) and P. maximowiczii (Japanese poplar). Thus, we found that major genes condition parasite-specific, nonhost resistance, as has been true in earlier studies of this kind with additional parasites of Populus spp. The selective force responsible for evolutionary maintenance of such genes is unknown. 相似文献
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J. E. van der Plank 《European journal of plant pathology / European Foundation for Plant Pathology》1969,75(1-2):45-52
There are two kinds of pathogenic races: those that interact differentially with varieties of the host plant, and those that do not. There are two kinds of resistance in the host: vertical resistance, when varieties of the host interact differentially with races of the pathogen, and horizontal resistance, when differential interaction is absent. There are two kinds of pathogenicity, defined here as virulence and aggressiveness, differentially interacting races differing in virulence, other races in aggressiveness. In relation to strong resistance genes, unnecessary virulence in a race reduces its fitness to survive and, with obligate parasites, also its aggressiveness; i.e. with obligate parasites unnecessary virulence and aggressiveness appear to be negatively correlated.Samenvatting Er zijn twee soorten van pathogene fysio's: die welke interactie, vertonen met rassen van de waardplant, en die welke dat niet doen. Er zijn twee soorten resistentie in de waardplant: verticale resistentie, wanneer rassen van de waardplant verschillend reageren op fysio's van het pathogeen, en horizontale resistentie, wanneer dit niet het geval is. Er zijn twee soorten pathogeniteit, hier omschreven als virulentie en agressiviteit; de eerstgenoemde fysio's verschillen in virulentie, andere fysio's in agressiviteit. In verband met sterke resistentiegenen reduceert onnodige virulentie in een fysio de overlevingskans en, bij obligate parasieten, ook de agressiviteit; dit wil zeggen dat bij obligate parasieten onnodige virulentie en agressiviteit negatief gecorreleerd zijn. 相似文献
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Roberto L. Nicastro Mário E. Sato Valter Arthur Marcos Z. da Silva 《Phytoparasitica》2013,41(5):503-513
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
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BACKGROUND: Rice brown planthopper, Nilaparvata lugens Stål, is a primary insect pest of cultivated rice, and effective control is essential for economical crop production. Resistance to neonicotinoid insecticides, in particular imidacloprid, has been reported as an increasing constraint in recent years. In order to investigate the extent of resistance, 24 samples of N. lugens were collected from China, India, Indonesia, Malaysia, Thailand and Vietnam during 2005 and 2006. Their responses to two diagnostic doses of imidacloprid (corresponding approximately to the LC95 and 5 × LC95 of a susceptible strain) were examined. RESULTS: Ten of the 12 samples collected during 2005 were found to be susceptible to imidacloprid, but two late‐season samples from India showed reduced mortality at both diagnostic doses. All 13 strains collected in 2006 showed reduced mortality at both doses when compared with the susceptible strain. Dose–response lines showed resistance in one of the most resistant field strains to be approximately 100‐fold compared with the susceptible standard. CONCLUSION: The data demonstrate the development and spread of neonicotinoid resistance in N. lugens in Asia and support reports of reduced field efficacy of imidacloprid. Copyright © 2008 Society of Chemical Industry 相似文献
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A German cockroach (Blatella germanica (L)) strain, Apyr‐R, was collected from Opelika, Alabama after control failures with pyrethroid insecticides. Levels of resistance to permethrin and deltamethrin in Apyr‐R (97‐ and 480‐fold, respectively, compared with a susceptible strain, ACY) were partially or mostly suppressed by piperonyl butoxide (PBO) and S,S,S,‐tributylphosphorotrithioate (DEF), suggesting that P450 monooxygenases and hydrolases are involved in resistance to these two pyrethroids in Apyr‐R. However, incomplete suppression of pyrethroid resistance with PBO and DEF implies that one or more additional mechanisms are involved in resistance. Injection, compared with topical application, resulted in 43‐ and 48‐fold increases in toxicity of permethrin in ACY and Apyr‐R, respectively. Similarly, injection increased the toxicity of deltamethrin 27‐fold in ACY and 28‐fold in Apyr‐R. These data indicate that cuticular penetration is one of the obstacles for the effectiveness of pyrethroids against German cockroaches. However, injection did not change the levels of resistance to either permethrin or deltamethrin, suggesting that a decrease in the rate of cuticular penetration may not play an important role in pyrethroid resistance in Apyr‐R. Apyr‐R showed cross‐resistance to imidacloprid, with a resistance ratio of 10. PBO treatment resulted in no significant change in the toxicity of imidacloprid, implying that P450 monooxygenase‐mediated detoxication is not the mechanism responsible for cross‐resistance. Apyr‐R showed no cross‐resistance to spinosad, although spinosad had relatively low toxicity to German cockroaches compared with other insecticides tested in this study. This result further confirmed that the mode of action of spinosad to insects is unique. Fipronil, a relatively new insecticide, was highly toxic to German cockroaches, and the multi‐resistance mechanisms in Apyr‐R did not confer significant cross‐resistance to this compound. Thus, we propose that fipronil could be a valuable tool in integrated resistance management of German cockroaches. © 2001 Society of Chemical Industry 相似文献
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《Pesticide biochemistry and physiology》1987,28(2):279-285
The role of esterases in malathion resistance in Culex tarsalis has been investigated. When larvae of a resistant and a sensitive strain were placed in water containing [14C]malathion, malathion penetrated to give initially similar internal levels. With resistant mosquitoes, after 15 min the internal malathion concentration decreased to low levels while the monoacid degradation products accumulated in the larvae and were excreted into the surrounding water, whereas in susceptible larvae the internal malathion level stayed high and was lethal. It is suggested that the decrease in internal malathion and the resulting resistance were caused by an active malathion carboxylesterase in the resistant strain. A specific assay for malathion carboxylesterase with [14C]malathion showed 55 times more activity in resistant than in susceptible larvae, whereas when general esterase activity was assayed with α-naphthyl acetate only 1.7 times the activity was found. Analyses by starch gel electrophoresis showed a peak of malathion carboxylesterase, 60-fold higher from resistant than from susceptible larvae, in a gel zone which did not stain for general esterase activity. General esterases that did not hydrolyze malathion showed different electrophoretic patterns in the two populations, which are likely due to the nonisogenic character of the strains. These results show that use of a specific assay and the demonstration of degradation of malathion in vivo are essential for assessment of the contribution of esterase activity to the malathion-resistant phenotype in mosquito populations. 相似文献
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小菜蛾对溴氰菊酯的抗性消退与抗性恢复动态 总被引：2，自引：0，他引：2
利用选育的抗溴氰菊酯小菜蛾 Plutella xylostella L. 品系第100代为虫源,在不接触任何杀虫剂条件下继代繁殖50代,观察了小菜蛾对溴氰菊酯的抗性消退动态;同时对消退过程中的小菜蛾施加溴氰菊酯选择压力和利用消退过程中的小菜蛾与抗性品系、非抗性品系杂交,观察了小菜蛾对溴氰菊酯的抗性恢复动态.结果表明:①小菜蛾对溴氰菊酯的抗性消退表现为1～15代较慢,15～25代较快,25代后又缓慢的趋势,抗性消退也使氯菊酯、氯氰菊酯交互抗性水平下降;②溴氰菊酯抗性消退过程中,当连续受到一定程度的溴氰菊酯选择压力时,抗性会在几代之内很快恢复;③与其它品系杂交的后代受到一定剂量溴氰菊酯连续处理后,3～4代就能达到或接近抗溴氰菊酯品系第100代的抗性水平,对氯菊酯、氯氰菊酯的交互抗性水平也随之迅速上升. 相似文献
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Two mosquito strains of Culex quinquefasciatus (Say), MAmCq(G0) and HAmCq(G0), were collected from Mobile and Huntsville, Alabama, respectively. MAmCq(G0) and HAmCq(G0) were further selected in the laboratory with permethrin for one and three generations, respectively. The levels of resistance to permethrin in MAmCq(G1) (after one-generation selection) and HAmCq(G3) (after three-generation selection) increased rapidly. Resistance to permethrin in MAmCq(G1) and HAmCq(G3) was partially suppressed by piperonyl butoxide (PBO), S,S,S-tributylphosphorotrithioate (DEF) and diethyl maleate (DEM), inhibitors of cytochrome P450 monooxygenases, hydrolases and glutathione S-transferases (GST), respectively, suggesting these three enzyme families are important in conferring permethrin resistance in both strains. A substitution of leucine to phenylalanine (L to F) resulting from a single nucleotide polymorphism (SNP), termed the kdr mutation, in the para-homologous sodium channel gene has been reported as a very common mutation associated with pyrethroid resistance of insects. A 341-bp sodium channel gene fragment, where the kdr mutation resides, was generated by PCR from genomic DNAs of Cx. quinquefasciatus strains. We found that the kdr mutation was present in both permethrin-selected and unselected HAmCq and MAmCq mosquito populations, suggesting that the kdr mutation plays the role in permethrin resistance. There was no significant change in the frequency and heterozygosity of the A to T SNP for the kdr allele between permethrin-selected and unselected MAmCq and HAmCq mosquitoes, indicating that other mechanisms are involved in the evolution of resistance in mosquitoes selected by permethrin in the laboratory. 相似文献
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近年来,广西番茄黄化曲叶病毒病(TYLCD)发生较为严重,病原也比较复杂(发现4种病毒且存在复合侵染现象),对广西的番茄生产造成了很大威胁,种植抗病品种是防治该病的关键措施。本研究对中国农科院蔬菜花卉所、上海市农科院园艺所、浙江省农科院蔬菜所、江苏省农科院蔬菜所、北京市农林科学院蔬菜研究中心和广西大学提供的43份抗TYLCD番茄品种在广西南宁的自然抗病性进行了评价。采用自然诱发的方法,病圃的番茄混合感染中国番茄曲叶病毒与中国番木瓜曲叶病毒。试验结果表明,表现高抗的品种有‘浙红3号’、‘浙红4号’、‘K22’、‘K64’等8个番茄品种,表现抗病和中抗的品种有‘红贝贝’、‘春展56’等25个品种,表现感病的品种有‘樱红1号’、‘K6’等5个品种,表现高感的品种有‘金陵佳玉’、‘苏粉11号’等5个品种。本试验结果为抗病番茄品种在广西乃至全国的推广和布局提供参考。 相似文献
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BACKGROUND: The B‐type Bemisia tabaci (Gennadius) has become established in many regions in China, and neonicotinoids are extensively used to control this pest. Imidacloprid resistance in a laboratory‐selected strain of B‐type B. tabaci was characterised in order to provide the basis for recommending resistance management tactics. RESULTS: The NJ‐Imi strain of B‐type B. tabaci was selected from the NJ strain with imidacloprid for 30 generations. The NJ‐Imi strain exhibited 490‐fold resistance to imidacloprid, high levels of cross‐resistance to three other neonicotinoids, low levels of cross‐resistance to monosultap, cartap and spinosad, but no cross‐resistance to abamectin and cypermethrin. Imidacloprid resistance in the NJ‐Imi strain was autosomal and semi‐dominant. It is shown that enhanced detoxification mediated by cytochrome‐P450‐dependent monooxygenases contributes to imidacloprid resistance to some extent in the NJ‐Imi strain. Results from synergist bioassays and cross‐resistance patterns indicated that target‐site insensitivity may be involved in imidacloprid resistance in the NJ‐Imi strain of B. tabaci. CONCLUSION: Although oxidative detoxification mediated by P450 monooxygenases is involved in imidacloprid resistance in the NJ‐Imi strain of B‐type B. tabaci, target‐site modification as an additional resistance mechanism cannot be ruled out. Considering the high risk of cross‐resistance, neonicotinoids should be regarded as a single group when implementing an insecticide rotation scheme in B. tabaci control. Copyright © 2009 Society of Chemical Industry 相似文献