A new resistance to pyrethroids in tribolium castaneum (herbst)

The characteristics of a new high-level, field-derived resistance to pyrethroids in Tribolium castaneum (Herbst) were investigated using impregnated-paper and treated-grain assays. Piperonyl butoxide almost completely suppressed the resistance, suggesting that the major resistance mechanism was microsomal oxidation. Resistance extended to all pyrethroids tested and to carbaryl but not to organophosphorus insecticides or to methoprene. Resistance was strongest against α—CN phenoxybenzyl cyclopropanecarboxylate pyrethroids and was correlated with structural modifications of the pyrethroid molecule, results also consistent with oxidative resistance. This resistance will ultimately result in failures to control T. castaneum if pyrethroids, such as deltamethrin, cypermethrin or cyfluthrin, are used in the field, even if they are synergised with piperonyl butoxide. The resistance does not jeopardise organophosphorus materials (e.g. fenitrothion, chlorpyrifos-methyl, pirimiphos-methyl, methacrifos) or methoprene.     

Control failure likelihood and spatial dependence of insecticide resistance in the tomato pinworm, Tuta absoluta

BACKGROUND: Insecticide resistance is a likely cause of field control failures of Tuta absoluta, but the subject has been little studied. Therefore, resistance to ten insecticides was surveyed in seven representative field populations of this species. The likelihood of control failures was assessed, as well as weather influence and the spatial dependence of insecticide resistance. RESULTS: No resistance or only low resistance levels were observed for pyrethroids (bifenthrin and permethrin), abamectin, spinosad, Bacillus thuringiensis and the mixture deltamethrin + triazophos (<12.5‐fold). In contrast, indoxacarb exhibited moderate levels of resistance (up to 27.5‐fold), and chitin synthesis inhibitors exhibited moderate to high levels of resistance (up to 222.3‐fold). Evidence of control failures was obtained for bifenthrin, permethrin, diflubenzuron, teflubenzuron, triflumuron and B. thuringiensis. Weather conditions favour resistance to some insecticides, and spatial dependence was observed only for bifenthrin and permethrin. CONCLUSION: Insecticide resistance in field populations of the tomato pinworm prevails for the insecticides nowadays most frequently used against them—the chitin synthesis inhibitors (diflubenzuron, triflumuron and teflubenzuron). Local selection favoured by weather conditions and dispersal seem important for pyrethroid resistance evolution among Brazilian populations of T. absoluta and should be considered in designing pest management programmes. Copyright © 2011 Society of Chemical Industry     

Effect of the combined treatment of insecticides and an attractant for the control of Phloeotribus scarabaeoides,a pest of Olea europea

Different insecticides have been tested for the control of the olive bark beetle, Phloeotribus scarabaeoides Bern. This scolytid can be managed at two points in its biological cycle: in pruned logs, where it excavates reproduction galleries, or in living trees, after emergence from the logs, where it digs feeding galleries. In mortality laboratory bioassays, the efficiency of organophosphorus insecticides has been ranked as follows: chlorpyrifos + dimethoate < formothion < methidathion. Formothion and methidathion, the two most efficient, were sprayed on olive logs together with a pyrethroid insecticide, deltamethrin, and a formulation which combined an organophosphorus (fenitrothion) and a pyrethroid (cypermethrin) insecticide. Deltamethrin inhibited the excavation of new reproduction galleries and induced a repellent effect on the olive pest. In contrast, none of the organophosphorus insecticides or the combination, fenitrothion + cypermethrin, were able to control the olive bark beetle. In olive trees, deltamethrin controlled this olive pest without showing the repellent effect observed for logs. Ethylene, a plant hormone, has been reported as an attractant for the olive bark beetle. The use of dispensers which released ethylene increased the number of P. scarabaeoides approaching the treated olive trees, thus favouring its use in a lure-and-trap control system.     

Cotton whitefly (Bemisia tabaci) resistance to organophosphate and pyrethroid insecticides in Pakistan

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.     

昆虫对拟除虫菊酯类杀虫剂的代谢抗性机制研究进展

随着拟除虫菊酯类杀虫剂在卫生和农业害虫防治中的广泛应用,昆虫对此类杀虫剂产生抗性的报道越来越多。目前已明确昆虫对拟除虫菊酯类杀虫剂的抗性机制包括表皮穿透率下降、靶标抗性以及代谢抗性,其中代谢抗性机制较为普遍,而且其与昆虫对多种杀虫剂的交互抗性关系密切。目前,随着基因组、转录组以及蛋白质组学等新技术的发展及应用,昆虫对拟除虫菊酯类杀虫剂的代谢抗性机制研究也取得了很多新进展。昆虫体内细胞色素P450酶（P450s）、羧酸酯酶（CarE）及谷胱甘肽S-转移酶（GSTs）等重要解毒酶系的改变均与昆虫对拟除虫菊酯类杀虫剂的代谢抗性有关,其中这3类解毒酶的活性及相关基因表达量的变化是昆虫对此类杀虫剂产生代谢抗性的主要原因。明确昆虫对拟除虫菊酯类杀虫剂的代谢抗性机制,对合理使用此类杀虫剂及延缓抗药性的产生均具有重要意义。本文在总结拟除虫菊酯类杀虫剂代谢路径及相关生物酶研究概况的基础上,综述了近年来有关昆虫对此类杀虫剂代谢抗性机制研究的主要进展。     

Pyrethroid insecticide resistance in British populations of the cabbage whitefly, Aleyrodes proletella

BACKGROUND: The cabbage whitefly, Aleyrodes proletella L., is emerging as a significant pest of field brassica crops in certain regions of the United Kingdom. In order to investigate the contribution of pesticide resistance to this phenomenon, A. proletella populations were sampled from five different areas in England in 2008 and 2009. Adult residual leaf‐dip bioassays were carried out using pyrethroid and neonicotinoid insecticides. RESULTS: Significant resistance to pyrethroids was found in multiple samples collected from two areas. No evidence of cross‐resistance to neonicotinoids was found in a subset of the pyrethroid‐resistant populations. While the patterns of resistance to different pyrethroids were broadly correlated, the magnitude of resistance factors differed substantially. Survival of strains at a putative diagnostic concentration of lambda‐cyhalothrin was found to provide a guide to their LC₅₀. Significant differences in LC₅₀ were found when different brassica crops were used in the bioassay, although the resistance patterns between strains were maintained. CONCLUSION: Reduced susceptibility to multiple pyrethroid insecticides exists in populations of A. proletella in the United Kingdom, corresponding to recent major outbreaks. The mechanism(s) of resistance are yet to be determined, but molecular structural differences in pyrethroids probably influence the magnitude of cross‐resistance within this group of insecticides. Copyright © 2011 Society of Chemical Industry     

Assessment of field evolved resistance to some broad-spectrum insecticides in cotton jassid, <Emphasis Type="Italic">Amrasca devastans</Emphasis> from southern Punjab,Pakistan

Resistance management, targeting insect pests is one of the key components in developing integrated pest management strategies. Arguably, resistance monitoring is a scientific undertaking that can support and inform resistance management tactics and strategies. To monitor the current resistance status in Amrasca devastans against conventional insecticides (deltamethrin, bifenthrin, cypermethrin, chlorpyrifos, profenofos, acephate, and methomyl) which are used by the farming community as the predominant means to control this pest. Field populations of A. devastans were collected from six different districts: Multan, Bahawalpur, Khanewal, Lahore, Dera Ghazi Khan and Muzaffargarh from Punjab in Pakistan. The adult populations tested were 11.10–92.87 times more resistant to deltamethrin, 5.87–14.11 times more to bifenthrin, 3.16–17.5 times more to cypermethrin, 2.65–36.42 times more to chlorpyrifos, 7.28–57.71 times more to profenofos, 1.65–11.13 times more to acephate and 2.55–43.31 times more to methomyl as compared to control (lab population). In our study, no to high levels of resistance were observed against pyrethroids and organophosphates. Development of resistance to these pyrethroids and organophosphates might be due to the injudicious use of these types of insecticides in field crops. This study suggests that use of these insecticides should be minimized to avoid development of resistance in A. devastans. Future studies are also recommended to use new chemistry insecticides with novel modes of action and/or insecticide mixtures that may reduce the reliance of the farming communities on these insecticides.     

Pyrethroids and the economics of pest management

Pyrethroid insecticides effect excellent control of a wide range of insect pest species at low cost to the user. In outlets where a broad spectrum of pests occur, alternative compounds are often more expensive and frequently have to be combined to provide an acceptable spectrum of control. The benefits of the pyrethroids have led to their extensive and often exclusive use in many of these outlets around the world. However, such dependency on a single class of chemistry brings with it the attendant threat of resistance. Pyrethroid resistance has now been documented in many species of insect around the world and for several of these, changing to other insecticides has meant large increases in the cost of control programs. Analysis of the US insecticide market has shown that in 1987 the average insecticide cost to a mid-south cotton grower was $32 acre^?1 (1 acre = 0-405 ha). A hypothetical case was examined where resistance to the pyrethroids occurred in one key pest, Heliothis virescens, the tobacco budworm. The level of resistance was defined such that 50 % of the normally pyrethroid-treated area was now treated with the most cost-effective alternative. Under these conditions, a mid-south grower would see the cost of insect control nearly double to $61-50 acre. Extrapolating such increases to the whole US cotton crop or to global cotton production would lead to increased insecticide costs of $230 × 10⁶ and $1-4 × 10⁹ per year, respectively. Making similar assumptions for all crops, the increased global costs of only a moderate amount of pyrethroid resistance could be as high as $2-4 × W⁹ annually. There is, thus, a very real need to maintain the pyrethroids as effective insect-control agents for as long as possible.     

Differential efficacy of three commonly used pyrethroids against laboratory and field‐collected larvae and adults of Helicoverpa zea (Lepidoptera: Noctuidae) and significance for pyrethroid resistance management

BACKGROUND: Helicoverpa zea (Boddie) pyrethroid resistance monitoring programs typically utilize cypermethrin in the adult vial test. Here we investigated if differences in insect growth stage and pyrethroid structure affect resistance ratios and discuss implications for pyrethroid resistance management. RESULTS: Vial bioassays with cypermethrin, esfenvalerate and bifenthrin were conducted on H. zea third instars and male moths from a susceptible laboratory colony and the F1 generation of a pyrethroid‐resistant field population. In the susceptible population, both growth stages were most sensitive to bifenthrin and adults were more sensitive to esfenvalerate than cypermethrin. LC₅₀ resistance ratios for the larvae and adults of the resistant population were approximately two times higher for bifenthrin than cypermethrin or esfenvalerate. CONCLUSION: For the resistant population, vial assays using either growth stage gave similar resistance ratios for each of the three pyrethroids, respectively, proving the adult vial test accurately reflects larval resistance. However, as resistance ratios varied considerably depending on the pyrethroid used, resistance ratio values obtained with one pyrethroid may not be predictive of resistance ratios for other pyrethroids. Our results suggest that carefully chosen pyrethroid structures diagnostic for specific mechanisms of resistance could improve regional monitoring programs. Copyright © 2009 Society of Chemical Industry     

Identification and expression profiles of nine glutathione S-transferase genes from the important rice phloem sap-sucker and virus vector Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae)

BACKGROUND: Glutathione S‐transferases (GSTs) have received considerable attention in insects for their roles in insecticide resistance. Laodelphax striatellus (Fallén) is a serious rice pest. L. striatellus outbreaks occur frequently throughout eastern Asia. A key problem in controlling this pest is its rapid adaptation to numerous insecticides. In this research, nine cDNAs encoding GSTs in L. striatellus were cloned and characterised. RESULTS: The cloned GSTs of L. striatellus belonged to six cytosolic classes and a microsomal subgroup. Exposure to sublethal concentrations of each of the six insecticides, DDT, chlorpyrifos, fipronil, imidacloprid, buprofezin and beta‐cypermethrin, quickly induced (6 h) up‐expression of LsGSTe1. The expression of LsGSTs2 was increased by chlorpyrifos, fipronil and beta‐cypermethrin. Furthermore, exposure of L. striatellus to fipronil, imidacloprid, buprofezin and beta‐cypermethrin increased the expression of the LsGSTm gene after 24 or 48 h. CONCLUSION: This work is the first identification of GST genes from different GST groups in Auchenorrhyncha species and their induction characteristics with insecticide types and time. The elevated expression of GST genes induced by insecticides might be related to the enhanced tolerance of this insect to insecticides and xenobiotics. Copyright © 2012 Society of Chemical Industry     

Incidence of pyrethroid‐resistant oilseed rape pests in Germany

BACKGROUND: Failures in pollen beetle control using pyrethroids since 2005 indicated pyrethroid resistance in Germany. Therefore, resistance monitoring using bioassays was established in Germany for oilseed rape pest insects. RESULTS: The spread and intensity of pyrethroid resistance of Meligethes aeneus increased from 2005 onwards, with no sensitive samples left in any region of Germany in 2011. Sensitivity also declined for the newly introduced actives bifenthrin, etofenprox (both class‐I pyrethroids) and tau‐fluvalinate; all three claimed to be less affected by resistance, although there was no clear cross‐resistance to lambda‐cyhalothrin (class‐II pyrethroid). In the German region with the longest tradition and high intensity of oilseed rape production, pyrethroid resistance of Psylliodes chrysocephala and Ceutorhynchus obstrictus, with resistance factors of up to 81 and 140 respectively, was detected. CONCLUSION: The intensive use of only one mode of action for many years is risky, because even pest insects with a low intrinsic resistance risk may develop resistance. Therefore, resistance strategies need to include several control options for pest insects needing regular treatments. Copyright © 2012 Society of Chemical Industry     

黑龙江省西部草原蝗虫田间种群的抗药性检测及治理

为明确黑龙江省西部草原蝗虫对杀虫剂的抗性,实现对草原蝗虫的高效节药治理,采用点滴法于2010年和2013年检测当地优势种大垫尖翅蝗Epacromius coerulipes不同种群对10种常规杀虫剂的敏感性,并测定3种增效剂对杀虫剂的增效作用.结果 显示,与相对敏感基线相比,2010年大垫尖翅蝗肇源、林甸和杜蒙种群对有...     

Control of tomato leafminer (Scrobipalpula absoluta) in Bolivia

Abstract

The leafminer Scrobipalpula absoluta Meyr. is a serious pest of tomatoes in the Los Valles region of the eastern foothills of the Bolivian Andes. An initial insecticide screening trial showed that the local population of S. absoluta had developed a high resistance to organophosphorous insecticides. Soil‐applied carbamates and Bacillus thuringiensis Berliner were also ineffective. Further trials were carried out to establish the optimum rates and timing of applications of two synthetic pyrethroids, fenvalerate and permethrin. The results showed that organophosphate‐resistant S. absoluta can be satisfactorily controlled under commercial growing conditions with tow doses of pyrethroid insecticides. Permethrin had greater toxicity and persistence than fenvalerate, and could be applied at longer intervals. It is recommended that permethrin, either as Ambush 50 e.c. at 100 ml/ha or as Pounce 30 e.c. at 170 ml/ha, be applied weekly or at 10–14‐day intervals at the beginning of the season or when infestations and damage are light.     

Pyrethroid resistance in the cotton bollworm,Helicoverpa armigera (Hübner), in West Africa

The susceptibility of Helicoverpa armigera to pyrethroids has been investigated in West Africa by means of laboratory bioassays since 1985, the first year of widespread pyrethroid use. For some years, this survey has shown a tendency for the pest to become more tolerant to pyrethroids. During the 1996 growing season, farmers using calendar‐based spraying programmes reported control failures in various countries. The strong efficacy of cypermethrin on small larvae was confirmed in experimental plots, but the effect decreased quickly in successive instars. Bioassays performed on resistant strains revealed an increase in LD₅₀ that was related to different resistance mechanisms. Metabolic resistance (MFO) appears to be a possible primary mechanism of resistance to pyrethroids. Target modification (kdr) is involved to a small degree and esterases seem to appear only after additional selection pressure. © 2000 Society of Chemical Industry     

Insecticide resistance status of Aedes aegypti (L.) from Colombia

BACKGROUND: To evaluate the insecticide susceptibility status of Aedes aegypti (L.) in Colombia, and as part of the National Network of Insecticide Resistance Surveillance, 12 mosquito populations were assessed for resistance to pyrethroids, organophosphates and DDT. Bioassays were performed using WHO and CDC methodologies. The underlying resistance mechanisms were investigated through biochemical assays and RT‐PCR. RESULTS: All mosquito populations were susceptible to malathion, deltamethrin and cyfluthrin, and highly resistant to DDT and etofenprox. Resistance to lambda‐cyhalothrin, permethrin and fenitrothion ranged from moderate to high in some populations from Chocó and Putumayo states. In Antioquia state, the Santa Fe population was resistant to fenitrothion. Biochemical assays showed high levels of both cytochrome P450 monooxygenases (CYP) and non‐specific esterases (NSE) in some of the fenitrothion‐ and pyrethroid‐resistant populations. All populations showed high levels of glutathione‐S‐transferase (GST) activity. GSTe2 gene was found overexpressed in DDT‐resistant populations compared with Rockefeller susceptible strain. CONCLUSIONS: Differences in insecticide resistance status were observed between insecticides and localities. Although the biochemical assay results suggest that CYP and NSE could play an important role in the pyrethroid and fenitrothion resistance detected, other mechanisms remain to be investigated, including knockdown resistance. Resistance to DDT was high in all populations, and GST activity is probably the main enzymatic mechanism associated with this resistance. The results of this study provide baseline data on insecticide resistance in Colombian A. aegypti populations, and will allow comparison of changes in susceptibility status in this vector over time. Copyright © 2011 Society of Chemical Industry     

Insecticide resistance profiles can be misleading in predicting the survival of Myzus persicae genotypes on potato crops following the application of different insecticide classes

BACKGROUND: The accuracy of predicting the survival of insecticide‐resistant aphids following the application of commonly used insecticides from the carbamate, the pyrethroid, a mix of the two or the neonicotinoid chemical classes was evaluated in a potato field in Scotland. Equal proportions of five genotypes of the peach‐potato aphid, Myzus persicae (Sulzer), with none, resistance to dimethyl‐carbamates, resistance to pyrethroids or combinations conferring resistance to both chemical classes were released into potato field plots. The insecticides were sprayed separately onto these plots, the aphid populations were analysed after 6–8 days and the process repeated. RESULTS: For each assessment after the three separate spray events, plots treated with the carbamate had 48, 147 and 28%, those treated with pyrethroid 53, 210 and 89%, those treated with carbamate/pyrethroid 28, 108 and 64% and those treated with neonicotinoid 43, 55 and 11% of the numbers of M. persicae by comparison with untreated controls. Only the proportions of surviving aphids from the genotype containing no insecticide resistance traits and the genotype containing elevated carboxylesterases matched ratios predicted from the selective advantage afforded by the resistance traits alone. Survival of aphids from the other three genotypes that carried 1–3 of the insecticide resistance traits differed from expectations in all cases, possibly owing to physiological differences, including their vulnerability to predators and hymenopterous parasitoids present at the site and/or their carrying unknown insecticide resistance mechanisms. CONCLUSION: Control strategies based on knowledge of the genetically determined insecticide resistance profile of an M. persicae population alone are insufficient. Hence, other important factors contributing to aphid survival under insecticide pressure need to be considered. Copyright © 2012 Society of Chemical Industry     

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     

Insecticide resistance in houseflies from the middle east and North Africa with notes on the use of various bioassay techniques

The susceptibility to pyrethroid, organochlorine, organophosphorus and carbamate insecticides, of 20 strains of houseflies (Musca domestica L.) collected in the Middle East and North Africa, was assessed by topical application. No resistance to pyrethroids was found but most flies were resistant to DDT, gamma-HCH, organophosphorus and carbamate insecticides. Numerical factors of resistance for a susceptible and two different resistant strains, obtained using different bioassay techniques, were compared. High mortality (≥95%) was achieved with ‘resisted’ insecticides in tests with space sprays, but only low, variable mortality resulted from deposit tests. If this occurs under practical field conditions, moderately resistant populations of flies could be controlled by using space sprays containing comparatively high concentrations of active ingredient, but increased levels of deposit would be ineffective.     

草地贪夜蛾对杀虫剂的抗性研究进展

草地贪夜蛾Spodoptera frugiperda (J. E. Smith) 是一种杂食性害虫,原产于美洲热带和亚热带地区,于2019年1月在中国云南省首次被发现后,已迅速向广西、贵州、广东及湖南等地蔓延。草地贪夜蛾寄主广泛,常用化学防治药剂为有机磷类、氨基甲酸酯类和拟除虫菊酯类,田间抗性监测数据显示,其对上述 3 类常用药剂已达中至高等抗性水平。此外,已有研究证明氯菊酯抗性草地贪夜蛾对二嗪类杀虫剂茚虫威无交互抗性;同时已有关于草地贪夜蛾对氟苯虫酰胺和氯虫苯甲酰胺田间和室内抗性的报道,表明其对上述 2 种药剂存在极高的交互抗性风险。草地贪夜蛾的抗药性机理主要涉及表皮穿透性降低、解毒作用增强和靶标敏感性下降等几方面,其中代谢解毒作用增强和靶标敏感性下降是导致草地贪夜蛾对杀虫剂产生抗性的主要机制。文章综述了草地贪夜蛾对传统杀虫剂和新型作用机制杀虫剂的抗性现状及抗性机理等方面的研究进展,以期对当前中国的草地贪夜蛾田间防治及抗性研究和防控提供参考。     

Field evaluations of insecticide treatment regimens for control of the common bed bug,Cimex lectularius (L.)

BACKGROUND: Because bedbugs, Cimex lectularius L., have not been a problem in the USA for over 40 years, few insecticide products are labeled for their control. Most products that are labeled for bedbugs are pyrethroids. However, recent studies indicate that field‐collected bedbugs may be resistant to pyrethroids. There are also non‐pyrethroid products labeled for bedbugs, but, like the pyrethroids, none of these products has been evaluated for field efficacy. This study evaluated the efficacy of two insecticide treatment regimens for bedbugs in multi‐unit housing. Both of the treatments included multiple products currently being used by the pest management industry. RESULTS: The ‘traditional’ treatment consisted of applications of pyrethroid products and an insect growth regulator. The ‘novel’ treatment consisted of applications of non‐pyrethroid products. The traditional treatment significantly reduced the number of bedbugs from 39.8 ± 10.1 per unit prior to treatment to 2.2 ± 1.0 at the end of the test period (P = 0.02; 95% reduction). The number of live bedbugs in the ‘novel’ treatment was also significantly reduced from 71.4 ± 25.3 bedbugs per unit to 10.2 ± 4.4 after 8 weeks (86% population reduction). CONCLUSIONS: Although both treatment regimens reduced bedbug numbers, the fact that bedbugs were not eliminated after multiple applications suggests that the insecticides, applied at the current label rates, were inadequate. These results suggest that a more integrated approach to bedbug control is necessary in multi‐unit housing situations. Copyright © 2008 Society of Chemical Industry