Chlorfenapyr resistance in the spider mite Tetranychus urticae: stability, cross-resistance and monitoring of resistance

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.     

Dicofol resistance in Tetranychus cinnabarinus: resistance and stability of resistance in populations from Antalya, Turkey

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     

草地贪夜蛾耐低温能力研究

为阐明草地贪夜蛾的抗寒能力及越冬虫态,为其越冬区划和监测预警提供科学依据,本研究测定了草地贪夜蛾不同发育阶段在4种低温(-1O℃、-5℃、0℃和5℃)条件下的存活率,并通过计算机软件拟合死亡率回归方程,计算出LT50、LT90和LT99.结果表明:草地贪夜蛾在4种低温条件下处理2h后各虫态存活率均随处理温度降低而显著下...     

History,evolution, and consequences of insecticide resistance

The first inkling of what the future held with respect to pesticide resistance of arthropods may be found in 1897 writings concerning control difficulties with San Jose Scale (Quadraspidiotus perniciosus (Comstock)) and codling moth (Laspeyresia pomonella (L.)). Eighty-three years later, the ever-growing list of resistant species involved 14 orders and 83 families, and numbered 428 different insects and acarines, of which 61% are of agricultural importance and the remainder of medical/veterinary concern. The impact of this has been felt throughout the world, wherever insecticides are used, in terms of increased vector-borne disease, increased pesticide hazards in the environment, crop losses and poorer quality of products, increased production costs, pest resurgences and rise of secondary pests, and various socioeconomic repercussions. Along the way, much has been learned about the mechanisms of resistance and the genetic, biological, and operational parameters that enable pest populations to thwart man's best efforts at chemical control. The challenge that we now face is to utilize this knowledge in the development of management strategies that will suppress the eruption of multiresistance that presently threatens the successful management of numerous arthropod pests, and will avert similar problems with other pest species in the future.     

Pyrethroid resistance and cross‐resistance in the German cockroach,Blattella germanica (L)

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     

Resistance in the mosquito, Culex quinquefasciatus, and possible mechanisms for resistance

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.     

Insecticide resistance in the bollworm,Helicoverpa armigera from Indonesia

Helicoverpa armigera collected from cotton growing areas of South Sulawesi, Indonesia in 1987 and early 1988 were resistant to cypermethrin. It is suggested that the 86-fold resistance to cis-cypermethrin in 1987 and the 65-fold resistance to cis/trans-cypermethrin in 1988 are consistent with this being a major cause of failure to control the insects in cotton in this area. The second laboratory generation showed a 20-fold resistance to fenvalerate. The larvae collected in 1988 additionally had a 203-fold resistance to DDT and a 5.6-fold resistance to endosulfan. The results are discussed in relation to the fact that this is a further region in which Helicoverpa armigera has developed resistance to a number of pyrethroids.     

Characterization of the rust resistance gene present in the common bean cultivar Ouro Negro,the main rust resistance source used in Brazil

The main goal of the present work was to characterize the rust resistance (RR) gene present in the Mesoamerican common bean cultivar Ouro Negro, temporarily named Ur‐OuroNegro or Ur‐ON, which is the main RR source used in Brazil. The RR spectrum presented by cv. Ouro Negro was compared with those of other bean lines harbouring known RR genes when inoculated with nine selected races of Uromyces appendiculatus, the causal agent of bean rust. In addition, all bean lines were screened with molecular markers linked to Ur‐ON in order to identify additional evidence for the presence of alleles for this locus in the screened RR sources. The allelic relationships of Ur‐ON were tested with previously characterized RR genes from lines resistant to at least one race of the pathogen. Allelism tests were also carried out between cv. Ouro Negro and cvs CNC and CSW 643, important RR sources in Brazil harbouring unnamed RR genes. The results showed that the major dominant gene conditioning RR in cv. Ouro Negro is positioned at a locus distinct from those with which it was compared. It is proposed that this gene – or complex gene locus – is unique and be designated Ur‐14.     

西花蓟马抗药性研究进展

西花蓟马是世界范围内蔬菜和花卉上的重要害虫之一,使用化学药剂是防治西花蓟马的主要手段,目前西花蓟马已对有机氯、有机磷、氨基甲酸酯、拟除虫菊酯、阿维菌素和多杀菌素等多种杀虫剂产生了抗药性。本文从抗药性现状、抗性机制和抗性治理等几个方面介绍了国内外有关西花蓟马抗药性的研究进展。     

Insecticide resistance,control failure likelihood and the First Law of Geography

Insecticide resistance is a broadly recognized ecological backlash resulting from insecticide use and is widely reported among arthropod pest species with well‐recognized underlying mechanisms and consequences. Nonetheless, insecticide resistance is the subject of evolving conceptual views that introduces a different concept useful if recognized in its own right – the risk or likelihood of control failure. Here we suggest an experimental approach to assess the likelihood of control failure of an insecticide allowing for consistent decision‐making regarding management of insecticide resistance. We also challenge the current emphasis on limited spatial sampling of arthropod populations for resistance diagnosis in favor of comprehensive spatial sampling. This necessarily requires larger population sampling – aiming to use spatial analysis in area‐wide surveys – to recognize focal points of insecticide resistance and/or control failure that will better direct management efforts. The continuous geographical scale of such surveys will depend on the arthropod pest species, the pattern of insecticide use and many other potential factors. Regardless, distance dependence among sampling sites should still hold, following the maxim that the closer two things are, the more they resemble each other, which is the basis of Tobler's First Law of Geography. © 2016 Society of Chemical Industry     

白纹雏蝗抗寒特性和高温耐受力及其机制

为阐明白纹雏蝗Chorthippus albonemus抗寒和高温耐受能力及其抵御机制,本研究测定白纹雏蝗过冷却点、冰点值及其对高温的耐受力,并采用生理生化方法测定白纹雏蝗在24、28、32、36、40、44和48℃不同温度下抗逆物质的积累量和变化情况.结果 表明,白纹雏蝗卵的过冷却点值为-22.58℃,冰点值为-30...     

Indoxacarb resistance in the house fly, Musca domestica

Indoxacarb (DPX-MP062) is a recently introduced oxadiazine insecticide with activity against a wide range of pests, including house flies. It is metabolically decarbomethoxylated to DCJW. Selection of field collected house flies with indoxacarb produced a New York indoxacarb-resistant (NYINDR) strain with >118-fold resistance after three generations. Resistance in NYINDR could be partially overcome with the P450 inhibitor piperonyl butoxide (PBO), but the synergists diethyl maleate and S,S,S-tributyl phosphorothioate did not alter expression of the resistance, suggesting P450 monooxygenases, but not esterases or glutathione S-transferases are involved in the indoxacarb resistance. Conversely, the NYINDR strain showed only 3.2-fold resistance to DCJW, and this resistance could be suppressed with PBO. Only limited levels of cross-resistance were detected to pyrethroid, organophosphate, carbamate or chlorinated hydrocarbon insecticides in NYINDR. Indoxacarb resistance in the NYINDR strain was inherited primarily as a completely recessive trait. Analysis of the phenotypes vs. mortality data revealed that the major factor for indoxacarb resistance is located on autosome 4 with a minor factor on autosome 3. It appears these genes have not previously been associated with insecticide resistance.     

不同水稻品种对褐飞虱的抗性鉴定

采用分蘖盛期单株鉴定法初步测定了183个水稻品种对褐飞虱的抗性,筛选出19个高抗水稻品种,然后用水稻苗期群体筛选鉴定法和成株期自然种群鉴定法,进一步测定了19个初筛鉴定的抗性水稻品种对褐飞虱的抗性反应,结果表明：2个水稻品种（江农早1号和三粒寸）在3种鉴定方法条件下均表现为抗性或免疫水平。     

Pyrethroids, knockdown resistance and sodium channels

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.     

Pathogenic races,host resistance,and an analysis of pathogenicity

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.     

Buprofezin susceptibility survey, resistance selection and preliminary determination of the resistance mechanism in Nilaparvata lugens (Homoptera: Delphacidae)

BACKGROUND: Buprofezin has been used for many years to control Nilaparvata lugens (Stål). Assessment of susceptibility change in the insect is essential for maintaining control efficiency and resistance management. RESULTS: Eleven‐year surveys showed that most field populations were susceptible before 2004. However, substantially higher levels of resistance (up to 28‐fold) were found in most of the rice fields in China after 2004. A field population was collected and periodically selected for buprofezin resistance in the laboratory. After 65 generations (56 were selected), the colony successfully obtained 3599‐fold resistance to buprofezin. Synergism tests showed that O,O‐diethyl‐O‐phenyl phosphorothioate (SV1), piperonyl butoxide (PBO) and diethyl maleate (DEM) increased buprofezin toxicity in the resistant strain by only 1.5–1.6 fold, suggesting that esterases, P450‐monooxygenases and glutathione S‐transferases had no substantial effect on buprofezin resistance development. CONCLUSION: The results from this study indicate that N. lugens has the potential to develop high resistance to buprofezin. A resistance management program with rotation of buprofezin and other pesticides may efficiently delay or slow down resistance development in the insect. Further investigation is also necessary to understand the resistance mechanisms in N. lugens. Copyright © 2008 Society of Chemical Industry     

灰飞虱对杀虫剂抗药性的研究进展

灰飞虱对杀虫剂产生抗药性是其近年来暴发频繁的重要原因。本文综述了国内外关于灰飞虱抗药性的研究成果,包括灰飞虱抗药性的发展、交互抗性、抗性机理、抗性遗传及生物适合度等。田间灰飞虱种群对多种药剂产生了不同程度的抗药性,其中对新烟碱类药剂吡虫啉和昆虫生长调节剂噻嗪酮产生了高水平到极高水平抗性(抗药性倍数分别为44.6～108.8倍和超过200倍),对有机磷类药剂毒死蜱和乙酰甲胺磷(抗药性倍数分别为10～12.6倍和9～13倍)、氨基甲酸酯类药剂甲萘威和残杀威(抗药性倍数分别为29.8～45.3倍和40.1～131.5倍)和拟除虫菊酯类药剂高效氯氰菊酯和溴氰菊酯(抗药性倍数分别为7.8～108.8倍和12～21倍)产生了中等水平到高水平的抗药性,对氟虫腈、阿维菌素和噻虫嗪没有产生抗药性(抗性倍数5倍)。长期大面积使用化学药剂是灰飞虱产生抗药性的重要原因。因此,必须加强灰飞虱的抗性治理,以延缓其抗药性进一步发展。