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1.
Resistance to fumigants has been frequently reported in insect pests of stored products and is one of the obstacles in controlling these pests. The authors studied phosphine resistance and its physiological basis in adult insects of 12 populations of Tribolium castaneum (Herbst) (Tenebrionidae), ten populations of Rhyzopertha dominica (F.) (Bostrichidae) and eight populations of Oryzaephilus surinamensis L. (Silvanidae) from Brazil, and the possible existence of fitness costs associated with phosphine resistance in the absence of this fumigant. The bioassays for the detection of phosphine resistance followed the FAO standard method. The production of carbon dioxide and the instantaneous rate of population increase (r(i)) of each population of each species were correlated with their resistance ratios at the LC(50). The resistance ratio at LC(50) in T. castaneum ranged from 1.0- to 186.2-fold, in R. dominica from 2.0- to 71.0-fold and in O. surinamensis from 1.9- to 32.2-fold. Ten populations of T. castaneum, nine populations of R. dominica and seven populations of O. surinamensis were resistant to phosphine. In all three species there was significant association (P < 0.05) between respiration rate and phosphine resistance. The populations with lower carbon dioxide production showed a higher resistance ratio, suggesting that the lower respiration rate is the physiological basis of phosphine resistance by reducing the fumigant uptake in the resistant insects. Conversely, populations with higher r(i) showed lower resistance ratios, which could indicate a lower rate of reproduction of the resistant populations compared with susceptible populations. Thus, management strategies based on the interruption of phosphine fumigation may result in reestablishment of susceptibility, and shows good potential for more effective management of phosphine-resistant populations.  相似文献   

2.
Phosphine gas has been used world-wide for more than four decades as an ideal fumigant for disinfestation of stored grains and other commodities. Its use as a safe fumigant of stored products has become even more important with recent restrictions on the production of the only alternative, methyl bromide. Widespread resistance to phosphine has emerged in several species of stored-product insects in many countries, which in some instances may have caused control failures. Chemically, phosphine is a strong reducing agent and biological redox systems, especially the components of the mitochondrial electron transport chain, are probably the site of its action in insects. The oxidation of phosphine could produce reactive phosphorylating species and interactions of phosphine with biological redox systems have been reported to cause generation of highly reactive oxyradicals. This appears to be the basis of phosphine toxicity to insects, which differs from that of respiratory inhibitors such as hydrogen cyanide. Phosphine-resistant strains of several species of stored-product insects have been reported to absorb very small amounts of the compound compared to their susceptible counterparts. This reduced uptake in resistant insects appears to result from respiratory exclusion of phosphine. The overall mechanism of resistance also involves a detoxification process. Despite the likely involvement of oxyradicals in the insecticidal action of phosphine, the level of anti-oxidant enzymes in resistant insects is apparently not higher than that in their susceptible counterparts. The reduced uptake of the compound might be due either to the presence of a phosphine insensitive target site or to a membrane-based efflux system that excludes phosphine gas in resistant insects. Studies have indicated the oxygen uptake in mitochondrial preparations from susceptible and resistant insects to be equally sensitive to inhibition by phosphine in vitro. The nature of the phosphine-exclusion system in resistant insects has not been fully elucidated. The possibilities of controlling resistant insects with phosphine and prospects for developing new alternative fumigants are also discussed. © 1997 SCI.  相似文献   

3.
BACKGROUND: Resistance to spinosad and methoxyfenozide has been studied in several insect pests, but there is a lack of information on Spodoptera exigua (Hübner) in Mexico. Therefore, evidence for the development of resistance in this pest to both compounds was examined. The effects of methoxyfenozide on reproductive parameters of S. exigua adults were also determined.RESULTS: Third instars from a field population were exposed for 24 h to the LC(50) of spinosad or methoxyfenozide for over six generations (G(2)-G(7)). No significant reduction in susceptibility to either compound was detected for up to five generations. In G(7), LC(50) values for insects exposed to spinosad and methoxyfenozide were respectively 2.75-fold and 1.25-fold greater than for G(1) larvae. Oral treatment with methoxyfenozide reduced the fecundity and fertility of G(7) adults, confirming sublethal effects on reproduction. Finally, five populations (Se-La Floriza, Se-Lazareto, Se-Bachigualato, Se-Los Agustinos and Se-Villa de Arista) of S. exigua were collected from fields in three states of Mexico for resistance monitoring to spinosad and methoxyfenozide. With the exception of Se-Villa de Arista, the other populations showed significant resistance to spinosad, with resistance ratios between 16- and 37-fold, compared with a susceptible laboratory colony. In contrast, only one population (Se-Lazareto) showed significant resistance to methoxyfenozide (13-fold).CONCLUSION: Resistance management programmes should be established, particularly in areas where S. exigua has developed resistance to spinosad. Copyright (c) 2008 Society of Chemical Industry.  相似文献   

4.
BACKGROUND: Piperonyl butoxide (PBO) effectively synergises synthetic pyrethroids, rendering even very resistant insect pests susceptible, provided a temporal element is included between exposure to synergist and insecticide. This concept is now applied to carbamates and neonicotinoids. RESULTS: A microencapsulated formulation of PBO and pirimicarb reduced the resistance factor in a clone of Myzus persicae (Sulzer) from >19 000- to 100-fold and in Aphis gossypii (Glover) from >48 000- to 30-fold. Similar results were obtained for a strain of Bemisia tabaci Gennadius resistant to imidacloprid and acetamiprid, although a second resistant strain did not exhibit such a dramatic reduction, presumably owing to the presence of target-site insensitivity and the absence of metabolic resistance. Synergism was also observed in laboratory susceptible insects, suggesting that, even when detoxification is not enhanced, there is degradation of insecticides by the background enzymes. Use of an analogue of PBO, which inhibits esterases but has reduced potency against microsomal oxidases, suggests that acetamiprid resistance in whiteflies is largely oxidase based. CONCLUSION: Temporal synergism can effectively enhance the activity of carbamates and neonicotinoids against resistant insect pests. Although the extent of this enhancement is dependent upon the resistance mechanisms present, inhibition of background enzymes can confer increased sensitivity against target-site resistance as well as increased metabolism. .  相似文献   

5.
Abstract: The susceptibility of eggs, pupae and adults of Tribolium castaneum (Herbst) and adults of Rhyzopertha dominica (F.), (both phosphine-resistant strains) to phosphine at fixed concentration-time (ct) products, with either constant or increasing or decreasing concentrations was studied at 25 (± 1)°C. At lower ct products, falling concentrations of phosphine generally caused reduced insect mortality in all the three exposure periods in the range 12 to 72 h. However, in R. dominica, both increasing and decreasing concentrations were less effective than constant concentrations. At higher ct products, no significant change in the mortality response was observed in either species after exposure to constant or changing concentrations. The findings indicate the need to maintain sufficiently high concentrations of phosphine until the end of the fumigation period.  相似文献   

6.
Two populations of Hordeum leporinum have evolved resistance to paraquat within a small area in central Tasmania, Australia. One population (THL1) was more than 80-fold resistant to paraquat when treated in winter, compared with a susceptible population (THL4) collected nearby, whereas the other population (THL2) was only 19-fold resistant. Translocation of paraquat was examined in all three populations at warm and cool temperature regimes. Herbicide was applied to a basal section of the second leaf of plants kept in the dark and translocation measured after 16 h of dark and during a subsequent light period. Paraquat absorption into the treated leaf was uniformly high in susceptible and resistant populations, with >93% of the applied herbicide absorbed within 16 h in the dark at both temperatures. Translocation of paraquat out of the treated leaf was low in the dark, with <4% of the herbicide translocated to the remainder of the plant. More herbicide was translocated out of the treated leaves in susceptible plants in the dark, compared with resistant plants at both temperature regimes and more paraquat was translocated at warmer temperatures. Extensive basipetal translocation of paraquat to the rest of the plant occurred in susceptible plants following exposure of the treated plants to light. However, basipetal translocation was much reduced in resistant plants in the light and corresponded to the degree of resistance. Resistance to paraquat in H. leporinum is the result of reduced translocation of paraquat out of the treated leaves.  相似文献   

7.
小菜蛾对杀虫双的抗性遗传研究   总被引：14，自引：1，他引：13  
利用室内选育的敏感品系和抗杀虫双品系为亲本,采用剂量对数—死亡机率值回归线(LD-P线)分析法,研究了小菜蛾对杀虫双的抗性遗传方式。结果表明,小菜蛾对杀虫双的抗性为多基因、常染色体遗传,正、反交F_1的显性度(D)值分别为0.39、0.28,即其主效基因为不完全显性。小菜蛾对杀虫双的抗性现实遗传力较低,h~2=0.052,产生抗性的速率较慢,室内选育119代,抗性仅达122.8倍。抗杀虫双品系和遗传杂交后代(F_1、F_2、BC)对拟除虫菊酯类、氨基甲酸酯类、有机磷类的代表杀虫剂溴氰菊酯、灭多威、敌敌畏等的交互抗性测定结果表明,它们对3种杀虫剂无交互抗性;亲本和杂交后代的多功能氧化酶环氧化活性与杀虫双的抗性水平呈正相关性;乙酰胆碱酯酶活性要比敏感品系低;羧酸酯酶活性与敏感品系无明显差异。  相似文献   

8.
Malathion resistance of a field-collected population of Rhizopertha dominica (Coleoptera: Bostrichidae) from Mexico was evaluated and the resistance mechanisms were characterized both in vivo and in vitro. The Mexican population showed a resistance level of 50-fold at LC50 as compared with that of a susceptible laboratory population. Malathion bioassays with the synergists triphenyl phosphate, piperonyl butoxide and diethyl maleate suggested that esterases were likely to contribute to the resistance whereas cytochrome P450 monooxygenases and glutathione S-transferases were not. In-vitro assays of esterases indicated that the general esterase activity was 1·3-fold higher in the Mexican population than in the susceptible population. However, the phosphotriesterase activity in the resistant population was 3·7-fold higher than in the susceptible population. Significantly higher phosphotriesterase activity in the resistant population was further indicated by 3·4-fold increase of Vmax in enzyme kinetics and higher frequency of individuals with high phosphotriesterase activity in this population. All these findings suggested that phosphotriesterases play a role in malathion resistance in the Mexican population of lesser grain borer. © 1998 SCI  相似文献   

9.
Only a few of the registered insecticides against Cydia pomonella L. are still effective in areas where insecticide resistance has emerged in this pest. Resistance mechanisms are multiple, and their lone or cumulative effects in a single population are not completely understood. A detailed estimation of resistance spectrum is still required to define the suitable insecticides to use against a given population. The efficacy of ten insecticides was therefore investigated together with the resistance mechanisms expressed in four laboratory strains and 47 field populations of C. pomonella from five countries. Bioassays were performed using topical applications of diagnostic concentrations on diapausing larvae, and resistance mechanisms were analysed on adults emerging from control insects. All populations exhibited a reduced susceptibility to at least one insecticide when compared with the susceptible laboratory strain. Cross-resistances were observed between azinphos-methyl or phosalone and more recent compounds such as spinosad and thiacloprid. Resistances to azinphos-methyl, diflubenzuron, spinosad, tebufenozide and thiacloprid were significantly correlated with mixed-function oxidase activity, while increased glutathione-S-transferase and reduced non-specific esterase activities were correlated with resistance to azinphos-methyl and emamectin, respectively. Conversely, resistances to azinphos-methyl, tebufenozide and thiacloprid were negatively correlated with increased esterase activity. None of the observed mechanisms explained the loss of susceptibility of populations to chlorpyrifos-ethyl, and no significant correlation was detected between resistance to deltamethrin and the presence of the kdr mutation. The suitability of such non-target instars to monitor insecticide resistance in field populations is discussed.  相似文献   

10.
Systemic uptake bioassays using excised cotton leaves confirmed resistance to imidacloprid in a Guatemalan population of the tobacco whitefly Bemisia tabaci Gennadius. Polyacrylamide gel electrophoresis of naphthyl esterases identified the insects as B-types. Upon collection from the field, resistance was determined to be 58-fold relative to a susceptible strain originating in the Imperial Valley of California. Resistance levels increased to 126-fold in this population during its continuous exposure to systemically treated cotton. In biochemical investigations, there was no detectable NADPH-dependent mixed function oxidase metabolism of 14C-imidacloprid at any time during the selection process. In contrast, microsomal preparations from housefly abdomens readily produced significant amounts of the mono-hydroxy and olefin derivatives of the parent compound. Detoxification of imidacloprid by housefly MFOs may account for reports of lower toxicity of the insecticide towards this insect compared with whiteflies, despite similar binding properties between imidacloprid and the nicotinic acetylcholine receptors in both species.  相似文献   

11.
BACKGROUND: In order to investigate the extent of resistance of oriental fruit fly, Bactrocera dorsalis (Hendel), which is a widespread pest throughout tropical, subtropical and temperate fruit crops, 25 populations of this insect were collected from 13 sites in mainland China in 2007 and 2008. In addition, resistant strains were established that showed increasing development of resistance. RESULTS: Compared with the susceptible strain, one population of B. dorsalis expressed high resistance (RR = 70.4‐fold), 16 populations expressed medium resistance (11.5‐fold < RR < 25.8‐fold) and eight populations had low resistance or remained susceptible (1.4‐fold < RR < 8.9‐fold) to trichlorphon. As regards β‐cypermethrin, one population showed high resistance (RR = 44.0‐fold), nine populations expressed medium resistance (12.2‐fold < RR < 28.4‐fold), 14 populations expressed low or minor resistance (3.0‐fold < RR < 9.7‐fold) and one population remained susceptible (RR = 1.1‐fold). As regards avermectin, five populations had developed high resistance (44.3‐fold < RR < 104‐fold), seven populations expressed medium resistance (11.4‐fold < RR < 38.6‐fold) and three populations expressed low or minor resistance (3.5‐fold < RR < 5.6‐fold). A continuous resistance selection in the laboratory strain showed that the resistance ratios to trichlorphon, β‐cypermethrin and avermectin were 71.6‐fold, 333‐fold and 70.4‐fold respectively. CONCLUSION: The data provided a comprehensive survey of insecticide resistance in Bactrocera dorsalis in mainland China. All results suggested that early resistance management programmes should be established for restoring the efficacy of pesticide‐based control measures. Copyright © 2010 Society of Chemical Industry  相似文献   

12.

BACKGROUND

The fumigant phosphine is used all over the world for disinfestation of stored grains and commodities. Adults of 23 different populations of Tribolium castaneum from 10 different countries were evaluated for phosphine resistance using a modification of the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK). Adults were exposed to 3000 ppm and recorded for 5–270 min for their mobility.

RESULTS

Among the tested populations, high levels of phosphine resistance were recorded in populations from Brazil, Serbia, and Spain. No survivals were recorded after 7 days post exposure for eight of 23 in a tested population.

CONCLUSIONS

Our work revealed four scenarios: 1, quick knockdown–low (or no) recovery; 2, Slow knockdown–high recovery; 3, Quick knockdown–high recovery; and 4, Slow knockdown–low recovery. Our data indicate that post exposure period is critical for the evaluation and characterization of phosphine resistance. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

13.
BACKGROUND: The recent development of very high resistance to phosphine in rusty grain beetle, Cryptolestes ferrugineus (Stephens), seriously threatens stored‐grain biosecurity. The aim was to characterise this resistance, to develop a rapid bioassay for its diagnosis to support pest management and to document the distribution of resistance in Australia in 2007–2011. RESULTS: Bioassays of purified laboratory reference strains and field‐collected samples revealed three phenotypes: susceptible, weakly resistant and strongly resistant. With resistance factors of > 1000 × , resistance to phosphine expressed by the strong resistance phenotype was higher than reported for any stored‐product insect species. The new time‐to‐knockdown assay rapidly and accurately diagnosed each resistance phenotype within 6 h. Although less frequent in western Australia, weak resistance was detected throughout all grain production regions. Strong resistance occurred predominantly in central storages in eastern Australia. CONCLUSION: Resistance to phosphine in the rusty grain beetle is expressed through two identifiable phenotypes: weak and strong. Strong resistance requires urgent changes to current fumigation dosages. The development of a rapid assay for diagnosis of resistance enables the provision of same‐day advice to expedite resistance management decisions. © 2012 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.  相似文献   

14.
BACKGROUND: Knockdown resistance (kdr) mutation (L1014F) is a well‐defined mechanism of resistance to pyrethroids and DDT in many insect species. Sensitive detection of the mutations associated with resistance is a prerequisite for resistance management strategies. The authors have developed a new real‐time molecular diagnostic assay based on SimpleProbe®/melting curve analysis for large‐scale kdr genotyping in the wild population of Culex quinquefasciatus Say, the principal vector of bancroftian filariasis. Melting curve analysis is based on the thermal stability difference between matched and mismatched DNA duplexes. The application of SimpleProbe® chemistry in insects described here is novel in entomology research. RESULTS: The mosquitoes homozygous for knockdown‐resistant and knockdown‐susceptible allele showed melting peaks at 60.45 °C ( ± 0.25) and 64.09 °C ( ± 0.24) respectively. The heterozygous mosquitoes yielded both peaks at approximately 60.5 °C ( ± 0.2) and 64.20 °C ( ± 0.23). Among the 92 samples genotyped, 16 were found to be homozygous resistant, 44 homozygous susceptible and 32 heterozygous. Comparative assessments were made of all the reported methods for kdr genotyping. CONCLUSION: The present method is cheaper, faster, more reliable and versatile than other alternatives proposed in detecting correct kdr genotypes in mosquitoes. This is the first report using a single‐labelled hybridisation probe to detect point mutations in insect populations. Copyright © 2010 Society of Chemical Industry  相似文献   

15.
The levels of susceptibility of populations of the European red mite Panonychus ulmi (Koch) (Acarina: Tetranychidae) collected from apple orchards in the Bursa region of Turkey to the insecticides chlorpyrifos and lambda-cyhalothrin, were determined by a petri leaf disk—Potter spray tower method. When compared with the susceptible population, resistance ratios at the LC50 level ranged from 6.0- to 35.6-fold, and from 0.7- to 5.7-fold for chlorpyrifos and lambda-cyhalothrin, respectively. Kinetic parameters of general esterase activity with α-naphthyl acetate as substrate indicated that an increased activity was present in the resistant populations compared with the susceptible populations. In these strains, 1.5- and 2.2-fold higher Glutathione S-transferase (GST) activity was also detected with the substrate 1-chloro-2,4-dinitrobenzene. General esterase activity gel profiles of these populations were studied by native polyacrylamide gel electrophoresis, but no relationship between resistance ratios and band patterns was detected. The results of this study document a decreased efficacy of chlorpyrifos and lambda-cyhalothrin in field populations of P. ulmi in Turkey, possibly linked to altered activities of esterases and GST.  相似文献   

16.
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   

17.
不同地区小菜蛾种群的抗药性及酯酶同工酶的研究   总被引：9，自引：1，他引：8  
用淀粉凝胶电泳对中国 3个不同地理区域的小菜蛾种群和台湾敏感品系的抗性水平及酯酶同工酶进行了研究 ,结果发现 :生物测定显示 3个小菜蛾种群对杀虫双均没有明显的抗性 ;对阿维菌素的抗性分别为 1.2 1倍、4 .51倍和 1.2 5倍。在 Estα和 Estβ基因位点 ,北京种群中存在 11种同工酶 ,其中 4种为 α同工酶 ,7种 β/i>同工酶 ;河北种群中存在 3种 α同工酶 ,5种 β同工酶 ;云南种群中存在 3种 α同工酶 ,3种 β同工酶。 3个种群酯酶基因多态性的产生可能是携带不同抗性酯酶基因的小菜蛾被动运输的结果 ;杀虫双对于能引起酯酶活性升高的杀虫药剂可能无交互抗性。  相似文献   

18.
为探明臭氧对主要储粮害虫的熏蒸效果及其与磷化氢抗性的关系,本研究采用臭氧发生装置测定浓度为0.84 g/m^3臭氧对5种主要储粮害虫(赤拟谷盗、杂拟谷盗、玉米象、锈赤扁谷盗、谷蠹)的熏蒸效果,及对具有不同磷化氢抗性的赤拟谷盗(抗性系数为1.7~862.7)和杂拟谷盗(抗性系数为2.3~144.7)的毒力效果,并统计分析了试虫经臭氧熏蒸1 h后在不同时间内的行为状态差异。研究结果表明:在0.84 g/m^3臭氧浓度下,5种害虫对臭氧均具有较强敏感性,其LT50在0.58~1.53 h,其中谷蠹对臭氧的耐受性相对最强;赤拟谷盗和杂拟谷盗的不同磷化氢抗性品系对臭氧的敏感性差异较小,表明磷化氢与臭氧无交互抗性。经臭氧熏蒸1 h后,试虫有正常爬行、非正常爬行和死亡3种行为状态,其中较大比例的试虫(24%~66%)处于非正常爬行状态,且持续时间较长,约10 d后此部分试虫恢复正常或死亡。结果表明,臭氧对储粮害虫具有高效性和广谱性,且与磷化氢无交互抗性,可作为储粮害虫防治及磷化氢抗性治理药剂。  相似文献   

19.
昆虫对生物农药的抗性机制及对策   总被引：1，自引：0，他引：1  
本文综述了昆虫对B.t等生物杀虫剂的抗性机制及延缓昆虫抗性发展所应采取的措施。昆虫通过下列不同机制产生抗生：1）昆虫的血淋巴对B.t等生物杀虫剂的营养细胞的抑制作用。2）各种来源的蛋白酶对毒素蛋白的过度降解作用。3）昆虫中肠沉淀蛋白对毒素蛋白的沉淀作用。4）中肠上皮修复能力增强。5）中肠的吸附位点对毒素蛋白的亲和力下降。通过加强对B.t菌株的选育，合理科学的用药方式及采用不同的模式进行植物基因操作以提高杀虫蛋白的表达和活性等综合措施，减缓和降低昆虫抗性的发展。  相似文献   

20.
BACKGROUND: Bromus rigidus is a common weed species that has increased in cropping fields owing to limited control options. During a random field survey in Western Australia, six B. rigidus populations that had survived in‐crop weed control programmes were collected. The study aimed to determine the resistance profile of these six populations. RESULTS: Based on dose–response studies, all six B. rigidus populations had a low‐level resistance to sulfosulfuron and sulfometuron (both sulfonylurea herbicides) while remaining susceptible to herbicides with other modes of action. ALS in vitro activity assays revealed no differences in enzyme sensitivity between susceptible and resistant populations, while the use of malathion (a cytochrome P450 inhibitor) in combination with sulfosulfuron caused the resistant populations to behave like the susceptible population. CONCLUSION: This study established that these six B. rigidus populations have a low‐level resistance to the ALS‐inhibiting sulfonylurea herbicides, but are able to be controlled by other herbicide modes of action. The low‐level, malathion‐reversible resistance, together with a sensitive ALS, strongly suggest that a non‐target‐site enhanced metabolism is the mechanism of resistance. Copyright © 2012 Society of Chemical Industry  相似文献   

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