German cockroach resistance: Propoxur selection induces the same resistance spectrum as diazinon selection

A resistant laboratory strain of the German cockroach, Blattella germanica, was developed from a normal laboratory strain by selection with propoxur. Resistance to all insecticides except chlordane began increasing after 15 generations of selection and reached a plateau for most insecticides by generation 27. The resistant colony, designated B-strain, developed significant resistance to carbamates, organophosphorus compounds, pyrethrins and DDT, developed low resistance to gamma-BHC and no resistance to chlordane. The resistance spectrum, effect of synergists and inheritance of resistance of this propoxur resistant strain are similar to a diazinon resistant strain. Therefore, diazinon and propoxur may select for the same resistance mechanism(s) in this species. The practical implications of this research are discussed.     

甜菜夜蛾敏感品系的获得及其对12种杀虫剂的敏感基线

以高效氯氰菊酯为筛选药剂,通过室内单对汰选获得了甜菜夜蛾敏感品系,并采用浸叶法和点滴法测定该敏感品系对甲氨基阿维菌素苯甲酸盐、氯虫苯甲酰胺等12种常用药剂的敏感基线。浸叶法测得该品系对供试药剂的敏感性由高到低依次为:甲氨基阿维菌素苯甲酸盐(LC50为0.0340 mg/L)、茚虫威、氟啶脲、甲氧虫酰肼、氯虫苯甲酰胺、氟虫双酰胺、高效氯氰菊酯、虫酰肼、多杀菌素、毒死蜱、虫螨腈、灭多威(124.0482mg/L)。点滴法测得12种杀虫剂LD50由小到大依次为:高效氯氰菊酯、茚虫威、甲氧虫酰肼、甲氨基阿维菌素苯甲酸盐、虫酰肼、毒死蜱、多杀菌素、氯虫苯甲酰胺、虫螨腈、氟虫双酰胺、灭多威、氟啶脲。结果表明,该敏感基线可用于甜菜夜蛾的抗药性监测。     

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     

Effects of mode of testing on susceptibility to various insecticides of adults or larvae of Lucilia sericata,Chrysomya putoria and Musca domestica L

Relative potency of eight compounds (four pairs of similar types) to adults and old larvae of three species of cyclorhaphous diptera was determined by injection, oral or topical application. The following points emerged from comparisons of equitoxic doses: (a) C. putoria was consistently more susceptible than L. sericata. M. domestica was more susceptible to organochlorines than either of the blowflies, but less susceptible to organophosphorus, carbamate or pyrethroid insecticides; (b) the most potent insecticides (bioresmethrin, diazinon) were about equally toxic to adults and larvae of all species; but some compounds (especially DDT, gamma-BHC and propoxur) were relatively much less effective against larvae; (c) LD₅₀ values for oral treatments were higher than by injection, and those for contact treatments higher still. These “penetration factors” were highly correlated within each of the stages. This could be due to similarity in the cuticular barrier and (or) detoxication; (d) experiments with various synergistic compounds showed higher synergistic factors for larvae than adults (with DDT, bioresmethrin and propoxur). This probably indicates a more efficient detoxication system in the larvae, which is consistent with findings (b) and (c).     

Insecticide resistance inFrankliniella occidentalis: Corroboration of laboratory assays with field data and cross-resistance in a cypermethrin-resistant strain

Field efficacy of five insecticides to a greenhouse strain ofFrankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) of known resistance status was studied. In a greenhouse trial, the mortality of aF. occidentalis strain (Uncali) which exhibited resistance only against cypermethrin in laboratory assays, reached 56%, 68%, 82%, 94% and 99%, 24 h after application of abamectin, cypermethrin, endosulfan, malathion and methomyl, respectively. In the laboratory, for larval mortality equal to that achieved in the field, much lower doses — half of the field dose of cypermethrin and endosulfan, and one-third and one-sixth of malathion and methomyl, respectively, were required in topical application. Because of differences between laboratory and field responses ofF. occidentalis to insecticides, a sound resistance evaluation program to determine field efficacy of insecticides is needed. Resistance increased 28.0- and 139.3-fold at LC₅₀ in theF. occidentalis strain subjected to 27 and 44 cycles of cypermethrin selection, respectively. A slight cross-resistance of two- to threefold was found with endosulfan, malathion and methomyl and no cross-resistance was observed with abamectin. http://www.phytoparasitica.org posting August 4, 2008.     

Insect spiracle as the main penetration route of pyrethroids

The penetration route of adhered pyrethroids following direct aerosol spraying was studied in the German cockroach (Blattella germanica) by investigating the relationship between the application site of insecticide and knockdown efficacy. In direct spray, KT₅₀ was 26.4 s and the adhered amount of pyrethroid was 0.745 μg. On the contrary, required amount of pyrethroid to obtain the same KT₅₀ was one-eighth in topical application to the mesothoracic spiracle, while 2.6 times to the ventral mesothorax. KT₅₀ of cockroaches with blocked mesothoracic spiracles was greater than those with unblocked spiracles by 1.8-fold. The amount of directly sprayed pyrethroid penetrating through the inner wall of the mesothoracic trachea was significantly higher than the amount penetrating through the body wall of the ventral mesothorax. Therefore, the knockdown effect of the direct spray was believed to be caused by the flow of pyrethroids into the mesothoracic spiracles and its subsequent penetration through the inner wall of the mesothoracic trachea.     

Monitoring of resistance of insecticides in house fly (Musca domestica) populations in hungary

Samples of 24 house fly (Musca domestica L.) populations were collected from animal farms in Hungary in 1990 and kept in the laboratory to determine their susceptibility to different types of insecticide: organochlorines, organophosphates, carbamates, pyrethroids, macrocyclic lactone and insect growth regulators. The adulticides were tested with topical bioassay in all 24 populations, the larvicides were studied with treated larval medium in 16 populations. The data were expressed as LD₅₀ and LC₅₀ values (ng fly ?1 and mg kg ?1 larval medium respectively). The percentages of populations which had resistance ratios > 10 at LD₅₀ or LC₅₀ were: 63% to DDT, 50% to methoxychlor, 13% to lindane, 83% to malathion, 63% to trichlorfon, 4% to propetamphos, 96% to dioxacarb, 46% to propoxur, 4% to methomyl, 13% to pyrethrum, 96% to bioresmethrin, 63% to permethrin, 58% to cypermethrin, 79% to SK-80, 79% to deltamethrin, 38% to invermectin, 0% to diflubenzuron, 0% to cyromazine. Correlation analysis showed a high degree of positive correlation among the adulticides except for ivermectin, bioresmethrin and SK-80. No cross-resistance was found between the larvicides and the conventional adulticides. Differences of insecticide resistance levels among the populations surveyed were studied by principal component and factor analysis. A fairly good relationship between resistance status and control practices used on farms was revealed. The populations originating from those farms where the application of adulticides had been frequent or regular and where high resistance was shown to most chemicals could be separated from the others.     

Insecticide resistance in the tropical bedbug Cimex hemipterus

Insecticide resistance in the bedbug Cimex hemipterus was investigated using 4211 bedbugs collected from three districts of Sri Lanka. Insecticide bioassays were carried out with discriminating dosages of deltamethrin, permethrin, DDT, malathion, and propoxur. Activity levels of insecticide metabolizing enzymes and the insecticide target site acetylcholinesterase were monitored using biochemical assays. Percentage survivals after DDT, malathion, and propoxur exposure were 41-88%, 18-64%, and 11-41%, respectively. For deltamethrin and permethrin, KT₅₀/KT₉₀ (time to knock-down 50%/90% of the population) values were 0.5-24/1.0-58 and 1.3-10/2.5-47 h, respectively. Both elevated esterase and malathion carboxylesterase mechanisms were present in bedbug populations. Monooxygenase levels were heterogeneous. Organophosphate and carbamate target site acetylcholinesterase, was insensitive in 29-44% of the populations. High DDT resistance was probably due to glutathione S-transferases. Malathion carboxylesterases are mainly responsible for high malathion resistance. High tolerance to both DDT and pyrethroids suggests the presence of ‘kdr’ type resistance mechanism in one population.     

The status and development of insecticide resistance in Danish populations of the housefly Musca domestica L

Samples of housefly (Musca domestica) field populations were collected from Danish livestock farms in 1997. The tolerance of the first‐generation offspring was determined for a number of insecticides. Dose‐response values were obtained by topical application for the pyrethroids bioresmethrin and pyrethrum, both synergised with piperonyl butoxide, and the organophosphate dimethoate. The organophosphates azamethiphos and propetamphos and the carbamate methomyl were tested in discriminating dose feeding bioassays. Resistance was low to moderate in most of the populations for most of the compounds tested, but this study also revealed the existence of high resistance to pyrethroid, organophosphate and carbamate insecticides in some populations. The resistance factors at LD₅₀ for bioresmethrin/piperonyl butoxide ranged between 2 and 98, and for pyrethrum/piperonyl butoxide between 2 and 29. Our results indicate that pyrethroid resistance in Denmark is increasing, since four of the 21 farms showed more than 100‐fold resistance at LD₉₅, a level of resistance only observed once before. Resistance factors at LD₅₀ for dimethoate ranged from 9 to 100, and showed two distinct trends: populations with either decreasing or increasing resistance. Resistance to azamethiphos was found to be widespread and high. Although two strains with high methomyl and propetamphos resistance were observed, methomyl and propetamphos resistance is moderate and appears not to be increasing. © 2001 Society of Chemical Industry     

Comparative measurements of resistance to insecticides in three closely-related old and new world bollworm species

Toxicity measurements were made with three closely-related Bollworm species, Heliothis virescens F., Helicoverpa zea (Boddie), and Helicoverpa armigera (Huebner) using insecticides of 3 different chemical classes. Tests were carried out by a leaf-dip method using neonate larval stages, a topical application test on 3rd larvae, and a topical test with imagines. H. armigera populations from Ivory Coast, Turkey, Thailand, and India were obtained and investigated. H. virescens originated from the USA and Colombia, and H. zea from Guatemala and Nicaragua. Resistance was expressed in all species, the sensitive reference strains having similar LC₅₀s in tests with monocrotophos, profenofos, thiodicarb, and methomyl. Since resistance appeared not to be a quality related to species but rather a feature common to all of the samples investigated, its origin must be connected with the type of cotton culture and the selection pressure they were subjected to in their respective agro-ecosystem. Resistance was highest for monocrotophos and cypermethrin in Central American countries, differences in the treatment regime being reflected by the resistance levels attained. In all stages tested, resistance was sufficiently well expressed to make a monitoring system based on neonate larvae, the 3rd larval stage, or imagines of the species possible. The final decision as to which should be used for a general, comparative monitoring system, therefore, should be governed by the technical parameters of the testing process.     

Note: Insecticide resistance in<Emphasis Type="Italic">Helicoverpa armigera</Emphasis> from cotton-growing areas in Turkey

Insecticide resistance inHelicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most important constraints on cotton production in Turkey. We investigated the susceptibility ofH. armigera strains collected from cotton fields in the Adana, Hatay and Antalya provinces to insecticides which are in wide use. LD₅₀ values for tralomethrin, lambda-cyhalothrin, endosulfan, profenofos and methomyl were determined by topical bioassay. At the LD₅₀ levels, resistance ratios for tralomethrin were 24.7-, 19.7- and 15.7-fold in the Adana, Hatay, and Antalya strains, respectively; and for lambda-cyhalothrin were 41-, 20-and 40-fold, respectively. Resistance ratios ranged from 1.2- to 2.1-fold in all field strains for endosulfan, profenofos and methomyl, with no significant resistance. These results suggest the presence of resistance to tralomethrin and lambda-cyhalothrin inH. armigera strains collected from cotton fields, but no resistance to endosulfan, profenofos or methomyl could be observed.     

Current status of insecticide resistance in Q biotype Bemisia tabaci populations from Crete

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     

Resistance to bifenthrin and resistance mechanisms of different strains of the two-spotted spider mite (Tetranychus urticae) from Turkey

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.     

新疆棉铃虫自然敏感种群对常用杀虫剂浸叶法的毒力基线

选用阿拉尔棉铃虫自然敏感种群(AL-S),在详细观察2龄中期幼虫的形态、行为特征及比较其生理学特性对药剂敏感性影响的基础上,用生理特性一致的2龄中期幼虫,测定了10种常用杀虫剂浸叶法的毒力基线。结果表明:①2龄中期幼虫的形态和行为特征为头宽≤体宽,体色不透明肉色,体节明显且行动较敏捷。此时2龄幼虫的时龄约为10～22h,体重1.33±0.27mg;②试虫生理特性差异影响对药剂的敏感性。2龄幼虫不同发育历期的敏感性,以前期最敏感,中、后期较接近;雌蛾不同蛾龄的卵发育的2龄幼虫敏感性,以4日龄蛾卵的幼虫敏感性最低,7日龄蛾卵最敏感,5、6日龄蛾的敏感性相近,且介于上述二者之间。故在测定毒力基线时,为保持试虫生理同质性,宜选用5、6日龄雌蛾卵的2龄中期幼虫为佳。③用2龄中期幼虫,获得10种药剂浸叶法的毒力基线,杀虫剂致死中浓度(LC_(50))按以下次序增大:功夫菊酯、溴氰菊酯、氰戊菊酯、硫丹、甲基E605、辛硫磷、毒死蜱、丙溴磷、久效磷、灭多威。     

Geographic variability in response to azinphos‐methyl in field‐collected populations of Cydia pomonella (Lepidoptera: Tortricidae) from Argentina

BACKGROUND: Resistance to insecticides has been related to application history, genetic factors of the pest and the dynamic within the treated area. The aim of this study was to assess the geographic variation in azinphos‐methyl response and the role of esterase and cytochrome P450 monooxygenase enzymes in codling moth populations collected within different areas of the Río Negro and Neuquén Valley, Argentina. RESULTS: Diapausing field‐collected populations showed resistance ratios at the LC₅₀ that were 0.7–8.7 times higher than that of the susceptible strain. Mean esterase (EST) and cytochrome P450 monooxygenase activities (expressed as α‐N min^?1 mg^?1 prot^?1 and pg 7‐OHC insect^?1 min^?1 respectively) were significantly correlated with LD₅₀ values from the field‐collected populations. In addition, azinphos‐methyl response was associated with the geographic area where the insect population was collected: populations from isolated and more recent productive areas presented significantly lower resistance ratios in comparison with populations from older and more intensive productive areas. CONCLUSION: The populations assayed presented different resistance levels to azinphos‐methyl. The response was highly correlated with the orchard's geographic location. EST and ECOD activities were involved in azinphos‐methyl response in the given region. Copyright © 2012 Society of Chemical Industry     

Nicotinoid and pyrethroid insecticide resistance in houseflies (Diptera: Muscidae) collected from Florida dairies

BACKGROUND: The housefly, Musca domestica L., continues to be a major pest of confined livestock operations. Houseflies have developed resistance to most chemical classes, and new chemistries for use in animal agriculture are increasingly slow to emerge. Five adult housefly strains from four Florida dairy farms were evaluated for resistance to four insecticides (beta‐cyfluthrin, permethrin, imidacloprid and nithiazine). RESULTS: Significant levels of tolerance were found in most field strains to all insecticides, and in some cases substantial resistance was apparent (as deduced from comparison with prior published results). At the LC₉₀ level, greater than 20‐fold resistance was found in two of the fly strains for permethrin and one fly strain for imidacloprid. Beta‐cyfluthrin LC₉₀ resistance ratios exceeded tenfold resistance in three fly strains. The relatively underutilized insecticide nithiazine had the lowest resistance ratios; however, fourfold LC₉₀ resistance was observed in one southern Florida fly strain. Farm insecticide use and its impact on resistance selection in Florida housefly populations are discussed. CONCLUSION: Housefly resistance to pyrethroids is widespread in Florida. Imidacloprid resistance is emerging, and tolerance was observed to both imidacloprid and nithiazine. If these insecticides are to retain efficacy, producer use must be restrained. Copyright © 2009 Society of Chemical Industry     

Resistance risk assessment of two insect development inhibitors,diflubenzuron and cyromazine,for control of the housefly Musca domestica. part i: Larvicidal tests with insecticide-resistant laboratory and danish field populations

Larvicide tests with diflubenzuron (DFB) and cyromazine (CYR) were carried out against 15 laboratory housefly strains and 89 field strains collected from 87 Danish and 2 Swedish farms, 1975–89. The strains represented a wide range of adult insecticide resistance and R-mechanisms. The larvicide tests were done by treating larval medium with serial or discriminating dosages of the larvicide, seeding it with eggs and calculating the mortality during development to adults. The WHO susceptible strain (S) was used as a reference. Dose-response tests with DFB gave resistance ratios (R/S) from 1·1 to 4·1 at LC₅₀ and 0·3 to 3·4 at LC₉₅ and, with CYR, R/S from 0·6 to 1·8 at LC₅₀ and 0·6 to 2·9 at LC₉₅. It was concluded that the relatively small variation in susceptibility between strains was not generally correlated with resistance in adult flies to organophosphorus, pyrethroid or other conventional insecticides (neurotoxins). Tests with discriminating dosages of DFB (59 farms) and CYR (63 farms) showed no indication of resistance to either product. The results of investigations by other workers on the relation between resistance to DFB or CYR and resistance to conventional insecticides are discussed.     

Activity of two novel insecticides against permethrin-resistant Pseudoplusia includens

Two experimental insecticides, AC 303,630 and MK 244, were tested against a laboratory colony and three field strains of Pseudoplusia includens (Walker). Topical application bioassays indicated that permethrin resistance in the field strains ranged from 3.9 to 489.0-fold. In leaf dip bioassays, LC₅₀ and LC₉₀ values for AC 303,630 ranged from 6.7 to 15.1 mg litre ?1 and 8.7 to 28.2 mg litre ?1, respectively, for third-instar larvae. The Louisiana 1991 field strain was significantly more susceptible to AC 303,630 than the laboratory and other field strains. The LC₅₀ (but not LC₉₀) for the Louisiana 1992 field strain was significantly higher than that of the laboratory strain. However, there was no difference in toxicity of AC 303,630 between the field strain with the highest level of permethrin resistance and the laboratory strain. LC₅₀ and LC₉₀ values for MK 244 in leaf dip bioassays ranged from 0.014 to 0.023 mg litre ?1 and 0.079 to 0.174 mg litre ?1, respectively. There were no significant differences in LC 50 or LC 90 among any of the strains for MK 244. Field trials in soybean were also conducted in 1991 and 1992 in an area of Louisiana where permethrin efficacy against P. includens has declined. In both years, AC 303,630 at 0.11–0.22 kg ha ?1, and MK 244 at 0.0042–0.0084 kg ha ?1, provided significantly better control than permethrin at 0.11 kg ha ?1, and control equal to the recommended standard, thiodicarb. These studies indicate no cross-resistance exists between the experimental insecticides and permethrin.     

Insecticide resistance in Musca domestica L. from Eastern England

Strains of houseflies were obtained from a refuse tip and 34 farms selected at random from Eastern England in 1984. Resistance was assessed to four insecticides that had been in use for fly control in the UK. Dose-response data were obtained by topical application of the insecticides and, in addition, a resistance test method was used in which flies were allowed to feed on sugar coated with either methomyl or azamethiphos. For both methods, the knock-down (KD) after 48 h was used as a measure of response. The ranges of resistance factors for the topical application method were, for methomyl, 1·1–15·9 at KD₅₀ and 2·1–17·0 at KD₉₅; for azamethiphos, 2·2–36·9 at KD₅₀ and 4·5–88·2 at KD₉₅; for pyrethrins + piperonyl butoxide, 0·9–6·8 at KD₅₀ and 1·4–13·4 at KD₉₅; and for permethrin, 1·7–34·8 at KD₅₀ and 2·2–112·5 at KD₉₅. The ranges of the resistance factors for the feeding tests were, for methomyl, 2·1–39·8 at KD₅₀ and 2·4–64·0 at KD₉₅, and, for azamethiphos, 5·6–51·7 at KD₅₀ and 8·8–92·0 at KD₉₅.