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Arthropod herbivores cause dramatic crop losses, and frequent pesticide use has led to widespread resistance in numerous species. One such species, the two-spotted spider mite, Tetranychus urticae, is an extreme generalist herbivore and a major worldwide crop pest with a history of rapidly developing resistance to acaricides. Mitochondrial Electron Transport Inhibitors of complex I (METI-Is) have been used extensively in the last 25 years to control T. urticae around the globe, and widespread resistance to each has been documented. METI-I resistance mechanisms in T. urticae are likely complex, as increased metabolism by cytochrome P450 monooxygenases as well as a target-site mutation have been linked with resistance. To identify loci underlying resistance to the METI-I acaricides fenpyroximate, pyridaben and tebufenpyrad without prior hypotheses, we crossed a highly METI-I-resistant strain of T. urticae to a susceptible one, propagated many replicated populations over multiple generations with and without selection by each compound, and performed bulked segregant analysis genetic mapping. Our results showed that while the known H92R target-site mutation was associated with resistance to each compound, a genomic region that included cytochrome P450-reductase (CPR) was associated with resistance to pyridaben and tebufenpyrad. Within CPR, a single nonsynonymous variant distinguished the resistant strain from the sensitive one. Furthermore, a genomic region linked with tebufenpyrad resistance harbored a non-canonical member of the nuclear hormone receptor 96 (NHR96) gene family. This NHR96 gene does not encode a DNA-binding domain (DBD), an uncommon feature in arthropods, and belongs to an expanded family of 47 NHR96 proteins lacking DBDs in T. urticae. Our findings suggest that although cross-resistance to METI-Is involves known detoxification pathways, structural differences in METI-I acaricides have also resulted in resistance mechanisms that are compound-specific.

Estuarine environments are being constantly stressed by new sources of pollution (e.g. pesticides) derived from activities of industry and intensive agriculture. The present study aims at quantify pesticides of three different categories (fungicides, herbicides and insecticides) in the Louros River (Epirus region, North-Western Greece). A monitoring study of 34 compounds was carried out in surface river waters from June 2011 until May 2012. Seven water sampling stations were established and 35 water samples were collected. A solid-phase extraction (SPE) method coupled with gas chromatography–mass spectrometry (GC–MS) and liquid chromatography-mass spectrometry (LC-MS), depending on the compound, was developed and validated. During the monitoring study 25 pesticides were detected (13 herbicides, 9 insecticides, 3 fungicides). The most commonly encountered pesticides were quizalofop-ethyl, trifluralin and pendimethaline. Tebufenpyrad was found in all sampling stations and seasons, with the highest concentrations of 0.330 μg/L at Tsopeli Lagoon exceeding the rather low concentrations reported nationwide. Regarding the environmental risk due to the presence of target compounds in surface waters, this was estimated by calculating risk quotients (RQs) for different aquatic organisms (algae, zooplankton and fish). The results denoted a possible threat for the aquatic environment, rendering in this way the RQ method as a useful screening tool. In any case, further extensive study is needed for acetochlor, pirimiphos-methyl, endosulfan-a and azinphos-ethyl in order to better correlate their occurrence and potential toxic effects in aquatic life and humans.

A direct and facile cycloaddition reaction of electron-deficient terminal alkynes with 2,2,2-trifluorodiazoethane under mild conditions to afford a series of 5-substituted 3-trifluoromethylpyrazoles in high yields is described. The potential application of this cycloaddition reaction was demonstrated via the efficient synthesis of a key intermediate of the antiviral drug AS-136A and a fluorinated analog of Tebufenpyrad.

Spider mites are destructive arthropod pests on many crops and they have developed resistance to nearly all acaricides. In recent years, along with the application of high throughput sequencing, the molecular mechanisms of mite resistance had made a series of progress. But, the response in molecular level of mite exposure to acaricides, as well as the original mechanism of resistance development was still unclear. To disclose the deeply mechanisms, we used RNA sequencing to analyze the responses of mite exposure to a sublethal concentration (LC30) treatment of the three different action mode acaricides (Abamectin, Fenpropathrin, and Tebufenpyrad). A high number of differentially expressed genes may well be involved in detoxification and regulatory, with extensive overlap in differentially expressed genes between the three insecticide treatments. Two cytochrome P450 genes were co-up-regulated and one glutathione S-transferase genes were co-down-regulated in all the treatments, while carboxylesterase genes only had a response to abamectin. This interesting phenomenon revealed that P450 enzymes play an important role in the early stage of mite exposure to acaricide. Moreover, a P8 nuclear receptor gene was in response to stress caused by exposure to acaricides and RNA interference (RNAi) experiment indicated P8 nuclear receptor regulates the P450 enzyme activity and susceptibility of mites to acaricide. The differential response information of gene expression based on a large-scale sequence would provide some useful clues for studying the molecular mechanisms of mite resistance formation and development.

Tebufenpyrad and pyridaben are two agro-chemically important acaricides that function like the known mitochondrial toxicant rotenone. Although these two compounds have been commonly used to kill populations of mites and ticks in commercial greenhouses, their neurotoxic profiles remain largely unknown. Therefore, we investigated the effects of these two pesticides on mitochondrial structure and function in an in vitro cell culture model using the Seahorse bioanalyzer and confocal fluorescence imaging. The effects were compared with rotenone. Exposing rat dopaminergic neuronal cells (N27 cells) to tebufenpyrad and pyridaben for 3 h induced dose-dependent cell death with an EC 50 of 3.98 μM and 3.77 μM, respectively. Also, tebufenpyrad and pyridaben (3 μM) exposure induced reactive oxygen species (ROS) generation and m-aconitase damage, suggesting that the pesticide toxicity is associated with oxidative damage. Morphometric image analysis with the MitoTracker red fluorescent probe indicated that tebufenpyrad and pyridaben, as well as rotenone, caused abnormalities in mitochondrial morphology, including reduced mitochondrial length and circularity. Functional bioenergetic experiments using the Seahorse XF96 analyzer revealed that tebufenpyrad and pyridaben very rapidly suppressed the basal mitochondrial oxygen consumption rate similar to that of rotenone. Further analysis of bioenergetic curves also revealed dose-dependent decreases in ATP-linked respiration and respiratory capacity. The luminescence-based ATP measurement further confirmed that pesticide-induced mitochondrial inhibition of respiration is accompanied by the loss of cellular ATP. Collectively, our results suggest that exposure to the pesticides tebufenpyrad and pyridaben induces neurotoxicity by rapidly initiating mitochondrial dysfunction and oxidative damage in dopaminergic neuronal cells. Our findings also reveal that monitoring the kinetics of mitochondrial respiration with Seahorse could be used as an early neurotoxicological high-throughput index for assessing the risk that pesticides pose to the dopaminergic neuronal system.

Black, green, white, and Oolong teas, all derived from leaves of Camellia sinensis, are widely consumed throughout the world and represent a significant part of the beverages consumed by Americans. A gas chromatography-triple quadrupole-based method, previously validated for pesticides on dried botanical dietary supplements, including green tea, was used to measure pesticides fortified into black and green teas at 10, 25, 100, and 500 μg/kg. Teas from 18 vendors of tea products were then surveyed for pesticides. Of 62 black, green, white, and Oolong tea products, 31 (50%) had residues of pesticides for which no United States Environmental Protection Agency tolerances are established for tea. The following pesticides were identified on tea leaves, with concentrations between 1 and 3200 μg/kg: anthraquinone, azoxystrobin, bifenthrin, buprofesin, chlorpyrifos, cyhalothrin, cypermethrin, DDE-p,p', DDT-o,p, DDT-p,p', deltamethrin, endosulfan, fenvalerate, heptachlor, hexachlorocyclohexanes (α,β,γ,δ), phenylphenol, pyridaben, tebuconazole, tebufenpyrad, and triazophos. DDT-p,p' was found at much higher concentrations than DDE-p,p' or DDT-o,p' in 9 of 10 teas with DDTs. A comparison between three commercially available solid-phase extraction (SPE) column brands of the same type revealed that two brands of SPE columns could be interchanged without modification of the tea method.

Evidence continues to accumulate that pesticides are the leading candidates of environmental toxins that may contribute to the pathogenesis of Parkinson’s disease. The mechanisms, however, remain largely unclear. According to epidemiological studies, we selected nine representative pesticides (paraquat, rotenone, chlorpyrifos, pendimethalin, endosulfan, fenpyroximate, tebufenpyrad, trichlorphon and carbaryl) which are commonly used in China and detected the effects of the pesticides on mitochondria and ubiquitin-proteasome system (UPS) function. Our results reveal that all the nine studied pesticides induce morphological changes of mitochondria at low concentrations. Paraquat, rotenone, chlorpyrifos, pendimethalin, endosulfan, fenpyroximate and tebufenpyrad induced mitochondria fragmentation. Furthermore, some of them (paraquat, rotenone, chlorpyrifos, fenpyroximate and tebufenpyrad) caused a significant dose-dependent decrease of intracellular ATP. Interestingly, these pesticides which induce mitochondria dysfunction also inhibit 26S and 20S proteasome activity. However, two out of the nine pesticides, namely trichlorphon and carbaryl, were found not to cause mitochondrial fragmentation or functional damage, nor inhibit the activity of the proteasome, which provides significant guidance for selection of pesticides in China. Moreover, our results demonstrate a potential link between inhibition of mitochondria and the UPS, and pesticide-induced Parkinsonism.

A highly sensitive and selective method of pyraclostrobin, boscalid, tebufenpyrad and prohexadione-calcium determination under their combined presence in water sample, using high-performance liquid chromatography was developed. On the base of mentioned active ingredients (combined fungicide Bellis, insecto-acaricide Masai and plant growth regulator Regalis) pesticides may be used in one vegetation season for fruit trees protection. Method of co-determination of these substances is based on the preparation of water samples for extraction, extraction of pyraclostrobin, boscalid, tebufenpyrad and prohexadione-calcium, concentrating of extract of substances mixtures and chromatographic deter­mination with ultraviolet detection. A distinctive feature of this method is changing of ratio of components of mobile phase (mixture of acetonitrile and 0,1 % aqueous solution of phosphoric acid) in the process of chromatographic analysis, which allowed to clearly visualize test substances in case of their joint presence in one sample. Imple­mentation of developed and patented method into practice optimizes control over application of pesticides in agri­cul­ture and their monitoring in reservoirs water by significant acceleration of analysis and reduction of expenses in its carying out.

On the basis of complex I receptor protein binding site and commercial tebufenpyrad and tolfenpyrad, four series of novel pyrazole-5-carboxamides containing imine, oxime ether, oxime ester, and dihydroisoxazoline were designed and synthesized via the key intermediate 4-chloro-3-ethyl-N-(4-formylbenzyl)-1-methyl-1H-pyrazole-5-carboxamide. The structures of target compounds were confirmed by ¹H NMR and high-resolution mass spectrum (HRMS). The results of bioassays indicated that the target compounds possessed good-to-excellent activities against a broad spectrum of insects such as cotton bollworm (Helicoverpa armigera), spider mite (Tetranychus cinnabarinus), bean aphid (Aphis craccivora), and mosquito (Culex pipiens pallens), but gave different structure-activity relationships for each species. Compounds containing imine showed high insecticidal activity against cotton bollworm. Especially, stomach activity of compounds 5-1c was 60% at 11 mg kg⁻¹. The compounds also had good activities against bean aphid and mosquito. The foliar contact activity of compounds 5-1a, 5-1b, 5-1e, 5-3c, and 5-3d against bean aphid were 90, 100, 90, 90, and 90%, respectively, at 200 mg kg⁻¹. The activity of compound containing dihydroisoxazoline moiety (5-4) against mosquito was 60% at 1 mg kg⁻¹, which was near that of tebufenpyrad. The introduction of dihydroisoxazoline structure (5-4) was advantageous to improve the activity of the compound against adult mites compared with other structures; the miticidal activity of 5-4- against adult mites was 60% at 50 mg kg⁻¹.

Tetranychus macfarlanei (Tm-BB) Baker & Pritchard and Tetranychus truncatus (Tt-BJ) Ehara (Acari: Tetranychidae) were recently found in Bangladesh as pests in many crops. The susceptibility of eggs of both species to 14 acaricides and of adults to 11 acaricides was examined in the laboratory, using a rotary spray tower. LC50 values in female adults of Tm-BB and Tt-BJ indicated high susceptibility to all acaricides, except chlorfenapyr; LC50 of chlorfenapyr in Tm-BB was approximately 10 times higher than the recommended concentration (492 mg/l vs. 50 mg/l). Ratios of LC90 values and the recommended concentrations (i.e. resistance factor (RF)) indicated 117.07 and 1.16 fold resistance in Tm-BB adults against chlorfenapyr and spirodiclofen, respectively, whereas Tt-BJ appeared to be resistant to tebufenpyrad (RF = 1.65). The RF value of spirodiclofen in Tt-BJ adults was 0.90, suggesting that this should not be used for control of this species, to avoid the further development of resistance. Eggs of both spid...

The objective of this work was to establish a simple extraction method for the residual analysis of pyraclofos and tebufenpyrad in Perilla leaves. A QuEChERS (quick, easy, cheap, effective, rugged and safe) method was used for extraction using ethyl acetate as an extraction solvent, and cleanup was carried out using dispersive solid-phase extraction technique. The samples were analyzed using gas chromatography with nitrogen phosphorous detector and confirmed by gas chromatography-mass spectrometry. The linearity was excellent (r 2 =1.0) in matrix-matched calibration for both pesticides. The recoveries at two fortification levels were 80.76-95.38% with relative standard deviation lower than 5%. The limits of detection and limits of quantification were 0.01 and 0.033 mg/kg for both pesticides, respectively. The results revealed that the dissipation pattern of pyraclofos and tebufenpyrad followed first-order kinetics. The pyraclofos and tebufenpyrad residues declined to a level below the maximum residue limits within 14 day between the last application and harvesting. We suggest that pyraclofos and tebufenpyrad could be used efficiently on perilla leaves under the recommended dosage conditions. Copyright © 2012 John Wiley & Sons, Ltd.

The raspberry leaf and bud mite, Phyllocoptes gracilis (Nal.) is the most important secondary pest of raspberry in commercial production plantations in Serbia, which may cause significant damage to a raspberry planting if control measures are not carried out. In the past organophosphates and pyrethroids, insecticides with a wide activity spectrum and added acaricidal activity, were the main protection against this insect pest, partially resolving the issue. Besides them, endosulfan was widely used, an organochlorine substance known for its high efficacy in eriophyoid control. Nowadays, most of these substances are withdrawn from use or are facing withdrawal procedure. Except abamectin and milbemectin, insecticides recommended instead of organophosphates and other substances of older generations do not have significant activity against mites. Besides, P. Gracilis populations often reach high abundance, and after harvest in dryer years a more significant presence of two-spotted spider mite, Tetranychus urticae, is usually recorded, so acaricides have to be included in raspberry protection programs. Propargite, organotins (cyhexatin, fenbutatin-oxide), benzoylureas (flucycloxuron, flufenoxuron), and hexythiazox - acaricides of older and mid-generations still available on the market - proved to be efficient in eriophyoid control. Among acaricides commercialized in the last 15-20 years, a high activity against eriophyoids is exhibited by METI acaricides (fenazaquin, fenpyroximate, pyridaben, tebufenpyrad), diafenthiuron, chlorfenapyr, and tetronic acid derrivatives (spirodiclofen, spiromesifen). In order to improve the control of raspberry leaf and bud mite, laboratory and field research is needed with emphasis on biorational and alternative acaricides and their compatibility with the predatory mite Phytoseius macropilis Banks, which is an efficient natural regulator of P. gracilis in Serbian raspberry plantations.

Problems with Tetranychus urticae are frequently reported in protected crops in Italy, particularly in roses where many introduced acaricides show a progressive loss of effectiveness. We have conducted bioassays to assess the response of some Italian strains of T. urticae to a number of acaricides. These include compounds that were widespread and frequently used in the past, but also some recently registered compounds. We investigated two T. urticae strains collected from rose growers where control failures were reported (SAN and PSE), together with a strain collected from unsprayed vegetables (BOSA). Adult females of the rose strains (SAN and PSE) were resistant to tebufenpyrad (Resistant Ratio-RR, RR(50) = 48.4 and 163.6) and fenpyroximate (RR(50) = 74.1 and 25.9) when compared to the susceptible BOSA strain. Lethal concentrations for these products were higher than the registered field rate. The PSE strain proved to be highly resistant to abamectin (RR(50) = 1,294.1). Variation in bifenazate susceptibility was detected amongst strains, but LC(90) values of SAN and PSE were still in the range of the registered field rate. In egg bioassays, the SAN and PSE strains exhibited high resistance levels to clofentezine (RR(50) = 66,473 and 170,714), hexythiazox (RR(50) = 70,244 and 159,493) and flufenoxuron (RR(50) = 61.9 and 117.9). But the recently introduced ovi/larvicides etoxazole and spirodiclofen exhibited high activity on all strains. The activity of detoxifying enzymes such as esterases, glutathione-S-transferases (GSTs) and cytochrome P450 monooxygenases (MFOs) was determined in these strains as a preliminary attempt to identify potential resistance mechanisms. Enzymatic assays showed that the rose strains exhibited 2.66 and 1.95-fold increased MFOs activity compared to the susceptible strain. Assays for GSTs revealed that only the SAN strain exhibited a significantly higher activity. In contrast, only the PSE strain showed a significant higher hydrolysis of 1-naphthyl acetate.

On the basis of commercial insecticides tebufenpyrad and tolfenpyrad, two series of novel pyrazole-5-carboxamides containing α-hydroxymethyl-N-benzyl or α-chloromethyl-N-benzyl and pyrazoles containing 4,5-dihydrooxazole moieties were designed and synthesized via the key intermediate 2-amino-1-(4-substituted) phenyl ethanol. The structures of target compounds were confirmed by (1)H NMR and elemental analysis or high-resolution mass spectrum (HRMS), and their activities against cotton bollworm (Helicoverpa armigera), diamondback moth (Plutella xylostella), bean aphid (Aphis craccivora), mosquito (Culex pipiens pallens), and spider mite (Tetranychus cinnabarinus) were tested. The results of bioassays indicated that compounds containing α-chloromethyl-N-benzyl and compounds containing 4,5-dihydrooxazole showed high insecticidal activity against cotton bollworm. Especially, stomach activities of compounds Ij, Il, and IIe were 60% at 5 mg kg(-1). Moreover, the target compounds exhibited high selectivity between cotton bollworm and diamondback moth, although both of them belong to the order Lepidoptera. Although the activities against diamondback moth were at a low level, some of the target compounds exhibited antifeedant activity. The compounds also had good activities against bean aphid, mosquito, and spider mite. The foliar contact activity of compounds Ic, Id, Ie, and IIf against bean aphid were 95, 95, 100, and 95%, respectively, at 200 mg kg(-1). The miticidal and ovicidal activities of compound IIi against spider mite were both 95% at 200 mg kg(-1). Furthermore, a trivial change at 4-position of pyrazole ring would lead to great changes in properties and activities, which can easily be deduced by comparing the activities of compounds in series I (4-chloro-pyrazole compounds) with corresponding compounds in series II (4-hydro-pyrazole compounds), especially from the miticidal and ovicidal activities of Ii and IIi against spider mite.

Laboratory bioassays were conducted to determine the toxicity of different acaricides against two strains of Tetranychus merganser Boudreaux and two strains of Tetranychus kanzawai Kishida by probit analysis. The 50% lethal concentration (LC50) value and resistance ratio of the probit-concentration regression was considered to determine the resistance. A laboratory selected susceptible strain of T. kanzawai (Tk-JN) was used to compare the susceptible levels. Adult females of the T. merganser and T. kanzawai strains have little resistance to most of the acaricides. Adult females of the T. merganser Mexican (Tm-MP) strain were resistant to spiromesifen and the T. merganser Thai (Tm-TC) and T. kanzawai Kanaya (Tk-JT) strains were resistant to spirodiclofen and spiromesifen, because their LC50 values were higher than each of the recommended concentrations. For other chemicals, the LC50 values of all strains were lower than each of the recommended concentrations. Eggs of the Tm-MP strain were particul...

The tomato red mite, Tetranychus evansi Baker and Pritchard, is a herbivore specialized on solanaceous plants, which has rapidly spread through the world during the last decade. It causes serious damage to a variety of crops in Africa and Europe but has not yet been reported to damage solanaceous crops in Japan. Tetranychus evansi is known to occur in Japan and it has the potential to become a severe pest on solanaceous crops here as well. The present study determined the susceptibility of nine T. evansi strains from various countries to 11 acaricides, because chemicals will be used as the first line of control against a new pest when it starts to cause severe damage to crops. Bifenazate, cyenopyrafen, milbemectin, spirodiclofen and tebufenpyrad showed higher toxicity – as indicated by 50% lethal concentrations (LC50) – for imagocidal action, and chlorfenapyr showed higher LC50 for ovicidal action in almost all T. evansi strains, compared with a susceptible strain of Tetranychus kanzawai Kishida....

This paper reports the use of solarization and biosolarization to decontaminate a soil polluted with six insecticides (buprofezin, pirimicarb, pirimiphos methyl, pyridaben, pyriproxyfen and tebufenpyrad). In the experiment, 17-L pots filled with clay-loam soil were placed in a greenhouse during the summer season and then contaminated with the insecticides of interest. Treatments consisted of different solarization and biosolarization treatments, including a control without disinfection. For both solarization and biosolarization treatments, low-density polyethylene film was used as cover; the biosolarization treatment involving application of a mixture of sheep and chicken manures at a rate of 400 g pot(-1). Five pots per treatment were sampled periodically up to 90 d after the beginning of each treatment. The results showed that both solarization and biosolarization enhanced the degradation rates of most of the insecticides tested compared with the control, probably as a result of the increased soil temperature. Pirimicarb, pirimiphos methyl, tebufenpyrad, pyriproxyfen and pyridaben were degraded to a greater extent in the biosolarization than in the solarization treatment. The results confirm that both solarization and biosolarization can be considered as a remediation tool for soils polluted by these insecticides.

Recent population outbreaks of Tetranychus urticae Koch (red form) (Acari: Tetranychidae) were observed in strawberry fields in southern Turkey. Growers frequently complained that acaricides becoming an inefficient means of controlling this polyphagous pest. Therefore, a laboratory based bioassay and biochemical tests were conducted to determine comparative acaricide resistance status of five fields and a lab population of T. urticae. Larval bioassays were conducted using etoxazole and spiromesifen, whereas adult bioassays were performed with abamectin and tebufenpyrad. Kinetic esterase and glutathione S-transferase (GST) enzyme activities were also determined using a microplate reader. When compared to the lab population, based on LC50 values, the resistance rations of field populations were found between 2.39-7.86, 6.80-15.39, 4.61-9.73, and 5.51-12.47-fold for abamectin, etoxazole, spiromesifen and tebufenpyrad, respectively. Total esterase and GST activities of field populations were much higher than of the lab population. A 7.72-10.69 mOD/min/mg protein and a 5.92-7.56 mOD/min/mg protein, esterase and GST enzyme activities were determined for field populations, respectively. Whereas these enzyme activities were found to be 3.83 and 5.49 mOD/min/mg protein for the susceptible lab population, respectively. The higher detoxification enzyme activities indicate that these two enzymes play an important role in metabolic pathway of acaricides in different T. urticae populations. © Systematic & Applied Acarology Society. Scientific Research Foundation of Beijing Normal University We are grateful to Prof Recep Ay (Suleyman Demirel University, Turkey) for his help in conducting biochemical analysis. Prof Waldemar Klassen and Jesus Preciado (University of Florida, TREC, FL, USA) for editing the manuscript. This study was supported by Scientific Research Foundation of Çukurova University as a M.Sc. thesis for senior author, project number: FYL-2016-6150.

To develop a less technique-dependent bioassay technique that can be conveniently used by practitioners or farmers in the field for the monitoring of acaricide resistance of the two-spotted spider mite, Tetranychus urticae Koch, a residual contact vial (RCV) method was established using a 5-ml glass vial coated with acaricides. The RCV bioassay procedures were optimized by using abamectin and tebufenpyrad, two widely used acaricides. The diagnostic concentrations causing 100% mortality within 8 h post-treatment in a susceptible strain of T. urticae was set at 30 and 60 ppm for abamectin and tebufenpyrad, respectively. The vial-coated pesticides were stable at least one year when stored at − 20 °C as determined by HPLC. There was no significant difference in the bioassay results in repeated RCV bioassay by three different experimenters, indicating its high reproducibility and reliability. RCV-based resistance monitoring of 15 field populations of mites revealed that abamectin resistance begins to spread but tebufenpyrad resistance is already prevalent in Korea. The RCV diagnostic kit, when used by practitioners or farmers on site, should provide crucial information for the selection of most suitable acaricides for different field populations of T. urticae.

The tarsonemid mite, Phytonemus ( Tarsonemus ) pallidus ssp. fragariae (Zimmerman), is a serious pest of strawberry throughout much of Europe and North America. Many of the plant protection products previously effective against the mite, which causes stunting and distorting of leaves and buds, reducing fruit yield and quality, are no longer available. Finding alternative acaricides for control is a priority. In two field trials, we tested 9 foliar applied plant protection products to determine the efficacy for control of Phytonemus pallidus , and to assess their effects on natural enemies. The products tested as foliar applications (dose ha −1 ) were; abamectin 18 g/l EC (250, 500, 750, 1250 ml), tebufenpyrad 20% WP (500 g), fenpyroximate 51.3 g/l SC (1.0 l), bifenazate > 90% WP (400 ml), spiromesifen 24 g/l SC (500 ml), acequinocyl 15.8% SC (1.0 l), spirodiclofen 240 g/l SC (400 ml), etoxazole 110 g/l SC, and the surfactant, Silwett L-77 (Heptamethyltrisiloxane 0.05% (50 ml)). Effective products were used in admixture with the surfactant to investigate potential increased efficiency against P. pallidus . In each experiment, two applications were applied to plants previously inoculated with P. pallidus . None of the products controlled the mite effectively when applied alone, but the addition of Silwett L-77 greatly improved control of the pest, particularly in combination with abamectin, etoxazole and tebufenpyrad. These treatments reduced P. pallidus mite numbers by 98, 85 and 80%, respectively. Many of the acaricidal products that are normally active against other species of Acari probably fail to control P. pallidus because of the inaccessibility of the mite within the fold of the young leaflets. In addition, the leaves of strawberry plants are more waxy and hairy than most other crops and are difficult to wet. Hence, significant improvement in efficacy of some products can be achieved if mixed with the silicone surfactant.

Radova S. (2010): Effect of selected pesticides on the vitality and virulence of the entomopathogenic nematode Steinernema feltiae (Nematoda: Steinernematidae). Plant Protect. Sci., 46: 83–88. The survival and infectivity of infective juveniles of the entomopathogenic nematode Steinernema feltiae (Rhabditida: Steinernematidae) were determined after being exposed to 8 insecticides (a.i. kinoprene, lufenuron, methomyl, metoxyfenozide, oxamyl, piperonyl-butoxide, pyriproxyfen, tebufenozide), 7 acaricides (a.i. azocyclotin, clofentezin, diafenthiuron, etoxazole, fenbutatinoxide, fenpyroximate, tebufenpyrad) and 4 fungicides (a.i. captan, fenhexamid, kresoxim-methyl, nuarimol) under laboratory conditions. S. feltiae was tolerant to all tested insecticides and fungicides, mortality during 72 hours varied from 2.26% to 18.68 % and from 7.04% to 8.86%, respectively. Acaricides with a.i. fenpyroximate and tebufenpyrad considerably influenced the S. feltiae ability to infect larvae of Tenebrio molitor. Tebufenpyrad caused 95% and fenpyroximate 85% reduction in S. feltiae virulence. These results suggest that S. feltiae can be applied in combination with all tested pesticides except the acaricides with a.i. tebufenpyrad and fenpyroximate.

Tetranychus urticae populations were collected from ten commercial apple orchards and their susceptibilities to 12 acaricides were tested using a leaf disc bioassay. The resistance of each T. urticae population was reported as the LC 50 value, the resistance ratio (RR) and the slope of the probit–concentration regression. Cross resistances of T. urticae populations were estimated using the Spearman's rank correlation coefficient. Most local populations showed low resistance levels (RR ≤ 10). Development of resistance to METI and pyrethroid acaricides differed among local populations. The highest RR value (154.6) was found in the Uiseong population to tebufenpyrad. The Geochang population was highly resistant, especially to METI and pyrethroid acaricides. T. urticae populations collected from Suwon, Chungju, Yeongju and Geochang showed moderate resistance (10 50 values of abamectin, chlorfenapyr, fenbutatin-oxide and milbemectin ranged from 0.06 to 0.2 mg/l, from 0.67 to 3.38 mg/l, from 10.12 to 40.85 mg/l and from 0.47 to 3.01 mg/l, respectively. We discuss possible cross-resistance to acaricides using Spearman's rank correlation coefficient.

The preparation of N-methylpyrazoles is usually accomplished through reaction of a suitable 1,3-diketone with methylhydrazine in ethanol as the solvent. This strategy, however, leads to the formation of regioisomeric mixtures of N-methylpyrazoles, which sometimes are difficult to separate. We have determined that the use of fluorinated alcohols such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation, and we have used this modification in a straightforward synthesis of fluorinated analogs of Tebufenpyrad with acaricide activity. Fil: Fustero, Santos. Universidad de Valencia; España Fil: Roman, Raquel. Universidad de Valencia; España Fil: Sanz Cervera, Juan F.. Universidad de Valencia; España. Centro de Investigaciones Principe Felipe; España Fil: Simon Fuentes, Antonio. Universidad de Valencia; España Fil: Cuñat, Ana. Universidad de Valencia; España Fil: Villanova, Salvador. Universidad de Valencia; España Fil: Murguia, Marcelo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

Bifenazate is a novel carbazate acaricide discovered by Uniroyal Chemical (now Chemtura Corporation) for the control of phytophagous mites infesting agricultural and ornamental crops. Its acaricidal activity and that of its principal active metabolite, diazene, were characterized. Bifenazate and diazene had high toxicity and specificity both orally and topically to all life stages of Tetranychus urticae and Panonychus citri. Acute poisoning was observed with no temperature dependency. No cross-resistance was found to mites resistant to several other classes of acaricides, such as tebufenpyrad, etoxazole, fenbutatin oxide and dicofol. Bifenazate remained effective for a long time with only about a 10% loss of efficacy on T. urticae after 1 month of application in the field. All stages of development of the predatory mites, Phytoseiulus persimilis and Neoseiulus californicus, survived treatment by both bifenazate and diazene. When adult females of the two predatory mite species were treated with either bifenazate or diazene, they showed a normal level of fecundity and predatory activity in the laboratory, effectively suppressing spider mite population growth. Even when the predators were fed spider mite eggs that had been treated previously with bifenazate, they survived. These findings indicate that bifenazate is a very useful acaricide giving high efficacy, long-lasting activity and excellent selectivity for spider mites. It is, therefore, concluded that bifenazate is an ideal compound for controlling these pest mites.

A field colony of Tetranychus urticae (Koch) resistant to dicofol was selected with dicofol successively for 20 generations to produce the DR-20 strain. Resistance and multiple resistance levels of the DR-20 strain to 15 acaricides were determined using a spray bioassay. The DR-20 strain was extremely resistant to dicofol [resistance ratio (RR), 465]. The strain showed extremely strong resistance to acrinathrin (RR, 373) and benzoximate (RR, 197) and strong resistance to bromopropylate (RR, 136), fenbutatin oxide (RR, 65), fenpropathrin (RR, 70), fenpyroximate (RR, 68), and pyridaben (RR, 63). A RR of 11–29 was observed with abamectin, fenazaquin, milbemectin, propagite, and tebufenpyrad. The DR-20 strain exhibited low levels of resistance (RR p -nitroanisole- O -demethylation and 1.6-fold higher activities in both α- and β-naphthyl acetate hydrolysis. Synergist experiments with different metabolic inhibitors revealed that piperonyl butoxide, iprobenfos, triphenyl phosphate, and 4, 4-dichloro-α-methyl benzhydrol had little or no synergistic activity in the susceptible and DR-20 strains. These results suggest that employment of certain acaricides with little multiple resistance will be useful for the management of dicofol resistance in the field.

A field colony of Tetranychus urticae (Koch) (Acari: Tetranychidae) resistant to pyridaben was selected with pyridaben successively for 20 generations to produce the PR-20 strain. Resistance and multiple resistance levels of the PR-20 strain to 15 acaricides were determined using a spray bioassay. The PR-20 strain was extremely resistant to pyridaben (resistance ratio [RR] = 240]. The strain exhibited extremely strong resistance to fenpyroximate (RR = 373) and acrinathrin (RR = 329) and strong resistance to benzoximate (RR = 84). An RR = 10–40 was observed with abamectin, fenazaquin, fenbutatin oxide, fenpropathrin, and tebufenpyrad. The PR-20 strain showed low levels of resistance (RR < 10) to azocyclotin, bromopropylate, chlorfenapyr, dicofol, milbemectin, and propargite. Synergist experiments with different metabolic inhibitors revealed that piperonyl butoxide (PBO), a mixed function oxidase (MFO) inhibitor, had the greatest effect on pyridaben resistance. PBO significantly caused pyridaben resistance in the PR-20 strain to drop to the full susceptibility level of the susceptible (S) strain. However, there was no significant difference in MFO activities measured using a model substrate between the S and PR-20 strains. These results suggest that use of certain acaricides with little multiple resistance or PBO will be useful for the management of pyridaben resistance in the field.

Sublethal effects of the mitochondrial electron transport inhibitor (METI) tebufenpyrad on Tetranychus urticae Koch females surviving treatment as eggs or immatures (or =90% mortality) were investigated in life-table assay. The developmental time of females that had survived treatment as eggs (2 mg/l) or larvae (2.5 mg/l) was 1 day longer, while that of protonymphs (2.5 mg/l) or deutonymphs (4 mg/l) was 2 days longer, in addition to reduced longevity and fertility, compared to control. The treatment significantly reduced the intrinsic rate of increase in female survivors: corresponding values were 0.258, 0.278, 0.207 and 0.209, respectively (0.307 in untreated females). The offspring age distribution was significantly affected by the treatment. Sublethal effect of tebufenpyrad and its impact on T. urticae management are discussed.

A highly sensitive and rapid biosensor test based on disposable screen-printed thick-film electrodes was developed, which is suitable for monitoring organophosphate and carbamate residues in foods of animal origin with increased fat contents such as milk. The wild-type enzyme was combined with three engineered variants of Nippostrongylus brasiliensis acetylcholinesterase (NbAChE), to obtain enhanced sensitivity. The sample pretreatment could be reduced to a minimum. There was no extraction or fat removal necessary. With the biosensor test paraoxon concentrations down to 1 microg/L could be detected in milk. The detection limit for carbaryl was 20 microg/L. Recovery rates for paraoxon and carbaryl in milk samples lay between 89 and 107%. Ten milk samples from local markets were tested both with the biosensor test and with standard chromatographic multiresidue methods. Two milk samples caused AChE inhibition rates of50%. Accordingly, 4 microg/L tebufenpyrad, 4 microg/L tetraconazole, and 2 microg/L bifenthrin were detected in one of these milk samples. The other milk sample contained 2 microg/L tebufenpyrad.

A field-collected strain (MR-VL) of the two-spotted spider mite, Tetranychus urticae Koch, exhibited strong resistance to bifenthrin, dicofol and fenbutatin oxide in comparison with a susceptible laboratory strain (LS-VL). The MR-VL strain was screened for cross-resistance with several currently used acaricides. Cross-resistance was detected with clofentezine (RR = 2631), dimethoate (RR = 250), chlorfenapyr (RR = 154), bromopropylate (RR = 25), amitraz (RR = 17), flucycloxuron (RR = 15) and azocyclotin (RR = 7). Abamectin, acequinocyl, bifenazate, tebufenpyrad and spirodiclofen did not show any signs of cross-resistance. Enhanced detoxification by increased activity of mono-oxygenases (MO) and esterases is at least partially responsible for the observed resistance and cross-resistance. MO assays with 7-ethoxycoumarin (7-EC) were optimised and 7-ethoxy-4-trifluoromethylcoumarin (7-EFC), a new MO-substrate, was evaluated for the first time in T urticae and proved to be a good alternative to 7-EC. Approximately 3- and 4-fold higher MO activity was detected with 7-EFC and 7-EC respectively in the MR-VL strain. Kinetic parameters of general esterase assays with 4-nitrophenyl acetate and 1-naphthyl acetate as substrate indicated that more esterases were present in the MR-VL strain. A first attempt was made to classify the esterases present in T urticae. Acetyl-, aryl- and carboxyl-esterases were detected with the use of inhibitors after separation by native PAGE. Glutathione-S-transferases did not seem to play any role in the observed resistance and no differences were detected when the general oxidative capacities of the two strains were compared.

A field colony of the Two-spotted spider mite, Tetranychus urticae (Koch), resistant to fenpyroximate was further selected with fenpyroximate 5SC for 20 generations at a selection pressure of 30-50% mortality (designated as FR-20 strain). Resistance and cross-resistance levels of the FR-20 strain to 18 acaricides were determined using a spray method. The FR-20 strain was extremely resistant to fenpyroximate [resistance ratio (RR) 252]. The strain exhibited extremely strong positive cross-resistance to acrinathrin (RR 196), and high levels of resistance to benzoximate (RR 55) and propargite (RR 64). Moderate levels of cross-resistance (RR 11-40) to abamectin, fenbutatin oxide, fenpropathrin, pyridaben, pyridaben + bifenthrin and tebufenpyrad were observed. The FR-20 strain showed low levels of resistance (RR < 10) to azocyclotin, bromopropylate, chlorfenapyr, chlorfenapyr + bifenthrin, chlorfenapyr + pyridaben, dicofol, fenazaquin and milbemectin. Synergist experiments with different metabolic inhibitors revealed that piperonyl butoxide had the greatest effect on the efficacy of fenpyroximate, followed by iprobenfos and triphenyl phosphate. In a comparative assay with detoxifying enzymes, the FR-20 strain showed 2.5-fold higher activity in p-nitroanisole-O-demethylation, and 2.5- and 2.2-fold higher activities in alpha- and beta-naphthyl acetate hydrolysis, respectively. These results suggested that enhanced activities of both mixed-function oxidases and esterases likely contribute to the fenpyroximate resistance of the FR-20 strain of T urticae.

Abamectin, Beauveria bassiana , buprofezin, pymetrozine, tebufenpyrad, acetamiprid and the coded product 60145 were tested in laboratory bioassays to determine their effects on the strawberry pests Anthonomus rubi , Lygus rugulipennis and Chaetosiphon fragaefolii and on the predatory species Phytoseiulus persimilis and Chrysoperla carnea . Abamectin, acetamiprid, tebufenpyrad and 60145 were the most effective insecticides against the pests. These four compounds all had some effect on P. persimilis , but acetamiprid was the least toxic (63% mortality after 48 h). Abamectin, tebufenpyrad and 60145 had no detectable effect on C. carnea larvae, whereas acetamiprid caused 38% mortality after 72 h. In field experiments where acetamiprid, 60145 and abamectin were tested against C. fragaefolii , acetamiprid was very effective at reducing numbers of the aphid. Naturally occurring beneficial anthocorid species were reduced in number but not eliminated in the acetamiprid treatment. In field tests acetamiprid, abamectin and thiacloprid were less effective against L. rugulipennis than the industry standard chlorpyrifos. Reductions were small but statistically significant in the acetamiprid and thiacloprid treatments. Fruit damage was also reduced in these treatments. There was no detectable effect of these insecticides on naturally occurring beneficial species.

This paper describes a method for the sensitive and selective determination of 24 new pesticide residues (azoxystrobin, trifloxystrobin, kresoxim-methyl, fenazaquin, indoxacarb, fenothiocarb, furathiocarb, benfuracarb, imidachloprid, dimethomorph, fenpyroximate, hexythiazox, tebufenpyrad, tebufenozide, difeconazole, fenbuconazole, flusilazole, paclobutrazol, tebuconazole, tetraconazole, bromuconazole, etofenprox, fenhexamid, pyridaben) in apple puree, concentrated lemon juice and tomato puree. A miniaturized extraction-partition procedure requiring small amounts of non-chlorinated solvents was used. The extracts are analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS) without any further clean-up step. The pesticides are separated on a reversed-phase polar column using a gradient elution. Fifty-five simultaneous MS-MS transitions of precursor ions were monitored (two or three for each pesticide). Studies at fortification levels of 0.001-0.020 and 0.010-0.200 mg/kg gave mean recoveries ranging from 76 to 106% for all compounds, except for imidacloprid, with (R.S.D.s) < or = 15%. The excellent sensitivity and selectivity of LC-MS-MS method allowed quantitation and identification at low levels also in difficult matrices with a run time of 20 min. With the developed method almost 100 samples of commercial fruit products (nectars, juices, purees) were analyzed. None of samples contained residues higher than 0.010 mg/kg.

Following failures to control the European Red Mite ( Panonychus ulmi ) using METI-acaricides in some apple orchards in the south of France, resistance to fenazaquin and tebufenpyrad was studied under laboratory conditions. Resistance ratios ranged from 19.8 to 28.8 and from 16.8 to 39.8, respectively, for fenazaquin and tebufenpyrad when compared to the most susceptible of the 2 reference populations. An examination of bioassays responses showed that resistance was higher with tebufenpyrad than with fenazaquin. The recommended field rates for these compounds corresponded only to the LC 95 for fenazaquin and the LC 70 for tebufenpyrad. These results confirm resistance development to METI-acaricides in ERM field populations and suggest it could be responsible for reduced persistence of mite control and in some cases for control failure in apple orchards.

Summary Soil-applied imidacloprid at full (125 g a.i. ha−1) and half approved doses gave levels of control of damson-hop aphid, (Phorodon humuli), similar to that provided by foliar spray(s) of tebufenpyrad on the aphid-susceptible dwarf hop cvs First Gold and Herald. On those cultivars, aphid control was unreliable on plots treated with quarter dose imidacloprid and was generally no better than on untreated plants. Aphids were virtually eliminated from the leaves by the end of July each year in all treatments consistent with the action of natural enemies. Aphid contamination of cones reflected the numbers on foliage at flowering time, but varied widely between years. Yields and percentage α-acids content of dried hops were unaffected by the numbers of aphids on leaves early in the season and in cones at harvest, but aphid contamination reduced the economic values of crops by as much as 80%. Few P. humuli colonised the partially aphid-resistant breeding line 23/90/08 before their numbers were regulated and consistent with natural enemy activity. Yields, percentage α-acids content, and commercial value of harvested cones were similar in all treatments on 23/90/08 whether or not plants were treated with aphicides. The commercial risks posed by P. humuli preclude substantial reductions in aphicide usage on aphid-susceptible dwarf hop cultivars, but future cultivars expressing a similar level of partial resistance to aphids as 23/90/08 should not need treatment with aphicides.

We evaluated three concentrations of tebufenpyrad (17.5, 15 and 12.5%) in strip formulations for controlling varroa mites, Varroa destructor Anderson and Trueman (2000), in honey bee colonies. We also included colonies treated with Apistan, CheckMite+, and untreated colonies in our evaluation. The three concentrations we evaluated reduced varroa populations but also reduced the amount of brood and adult bees when compared with untreated colonies and colonies treated with Apistan or CheckMite+. Alternative delivery methods, lower concentrations of tebufenpyrad, and the evaluation of related compounds are logical next steps in evaluating the varroacidal potential of tebufenpyrad and related compounds.

The successful use of chemical rotations to manage insecticide resistance requires reversion between alternate chemical applications. We tested a tebufenpyrad resistant population of Tetranychus urticae Koch after some 55 months laboratory culture without pesticide selection and found LC50 level resistance had dropped from 63.29- to 2.41-fold. However, the population was still heterogeneous with LC99 level resistance at 38.03-fold. It is likely that a lack of reversion contributed directly to the initial tebufenpyrad control failure.

This paper describes a number of test methods, to beused in a sequential scheme, for testing the side-effects ofplant protection products on anthocorid bugs. Orius laevigatuswas used as test species. A `worst case' laboratory method wasdeveloped for evaluating the effect on mortality of the nymphsand the reproduction of the adults. An extended laboratory methodgives information on the effect of pesticides on adults undermore natural conditions. A semi-field test is executed in smallplots under field (glasshouse) conditions. Finally a field testsimulates the conditions in a commercial crop. For harmfulchemicals, both a laboratory and a semi-field persistence testwas developed to determine the safety period after which thepredatory bugs can be re-introduced in the greenhouse withoutbeing adversely affected. The total result of this sequentialscheme should indicate whether, and with what restrictions, aparticular pesticide can be implemented in IPM programs in whichO. laevigatus is used for control of western flower thrips(Frankliniella occidentalis). Twenty-two pesticides were testedincluding five fungicides, twelve insecticides and fiveacaricides. The fungicides captan, carbendazim, sulphur, thiram,tolylfluanid and the insecticides or acaricides pymetrozine,pyriproxyfen, tebufenozide and hexythiazox were harmless in the`worst case' laboratory test and thus did not need furthertesting. Imidacloprid, diafenthiuron, lufenuron, tebufenpyrad,abamectin, pyridaben and bifenthrin were harmful in thesemi-field test and should, in the tested concentrations, betternot be used simultaneously with the predatory bug. Theinsecticide dichlorvos was found harmful but short-lived in thepersistence test; it should be used before the introduction ofthe predatory bug O. laevigatus only when a safety period of 7days is respected. Pirimicarb was slightly toxic in thesemi-field test but short-lived. In IPM programs this aphicideshould be used at a low application frequency.

The behavior of 28 pesticides on two tomato cultivars with a different surface/weight (S/W) ratio of the berries (S/W, Birikino vs. Tombola) was studied, in order to provide appropriate indications about their persistence on crops reaching the pre-harvest interval (PHI). Quantitative analysis was performed using a GC MS/MS method. Birikino cv. (BIR) was a "cherry type tomato" with a double S/W ratio compared with Tombola cv. (TOM). The results showed a different pesticide behavior. Azoxystrobin, Boscalid, Bupirimate, Difenoconazole, Etofenprox, Iprodione, Mepanipyrim, Myclobutanil, Tebuconazole, Zoxamide, Metalaxyl M, Pyrimethanil, Tetraconazole, Benalaxyl, Cyprodinil, Fenamidone, Famoxadone and Fludioxonil immediately after treatments showed residues on BIR higher than TOM, and this behavior is consistent with its greater exposed surface. BIR showed higher decay rates of these pesticides during the whole trial, nevertheless residue averages remained higher than TOM reaching the time of harvest. Residues at the PHI were all below their Maximum Residue Levels (MRLs), but data indicated that they could exceed their legal limits especially if the above-mentioned active ingredients were employed more than once per crop cycle on cherry type tomatoes. As regards to Chlorpyrifos, Chlorpyrifos methyl, Triadimenol, Pyridaben and Tebufenpyrad, no different residual behavior related to S/W ratio of the cultivars was observed. Even in this case, residues at the PHI were all below MRLs. As for Cyfluthrin, Deltamethrin, Lambda cyhalothrin, Etoxazole and Cyproconazole, residues were lower than the limit of quantitation (LOQ) of the analytical method just after the treatment, according to their low doses of employment.

Mitochondria are suggested to play a central role in ageing and evolution of longevity. Gradual decline in mitochondrial function during ageing and concomitant increase in production of reactive oxygen species (ROS) leads to oxidative damage of macromolecules and impairment of ATP synthesis. To assess relationship between ageing and oxidative stress resistance we exposed different longevity lines of the seed beetle (Acanthoscelides obtectus) to four concentrations of tebufenpyrad, mitochondrial complex I inhibitor. Complex I is one of main sites of ROS production during normal respiration and its inhibition elevates oxidative stress. Our results showed that 24 h of exposure to tebufenpyrad decreased survival and post-stress longevity due to increased baseline mortality. Higher resistance was recorded in beetles from lines selected for late reproduction and extended longevity (L) than in early reproducing beetles (E). Also, females were more resistant than males. Since complex I is under dual genetic control, our second aim was to disentangle relative contribution of nuclear and mitochondrial genes to the variation in longevity. We used crossed combinations of distinct mitochondrial and nuclear genotypes (E x L, L x E) and compared them to control hybrids where mitochondrial genome was ``transplanted{''} onto the original background (E x E, L x L). Our study revealed significant effect of nucleus, i.e. higher survival and post-stress longevity in beetles harbouring L nucleus. Mitochondrion effect was significant only within L nuclear background where E mitochondrion gave advantage. Ministry of Education, Science and Technological Development {[}173007]

In this contribution we report the synthesis of fluorinated and nonfluorinated tebufenpyrad analogues to explore potential druglike properties through the phenotypic screening as part of the Lilly Open Innovation Drug Discovery (OIDD) program.

A method for determination of trace amounts of the pesticides tebufenpyrad and oxadiazon, previous solid-phase microextraction (SPME), was developed using gas chromatographymass spectrometry and selected ion monitoring (GC-MS; SIM). Both pesticides were extracted with a fused silica fiber coated with 100 μm polydimethylsiloxane. The effects of pH ionic strength, sample volume, extraction and desorption times as well as extraction temperature were studied. The linear concentration range of application was 0.5–250 ng mL−1 for both compounds, with a detection limit of 0.06 ng mL−1 for tebufenpyrad and 0.02 ng mL−1 for oxadiazon. SPME-GC-MS analysis yielded good reproducibility (RSD between 7.5–10.1%). It was used to check the eventual existence of tebufenpyrad and oxadiazon above this limit in water and soil samples from Granada (Spain) as well as in human urine samples. The method validation was completed with spiked matrix samples. It can be applied as a monitoring tool for water, soil and urine in the investigation of environmental and occupational exposure to tebufenpyrad and oxadiazon.

A strain of Tetranychus urticae (Koch; Acari: Tetranychidae), collected from hops (Humulus humuli L; Cannabaceae) in England with a short history of tebufenpyrad use, exhibited resistance to four METI (mitochondrial electron transport inhibitor) -acaricides; tebufenpyrad, pyridaben, fenazaquin and fenpyroximate. Resistance factors for these compounds in a micro-immersion assay were 46, 346, 168 and 77 respectively, and corresponded to those exhibited by a Japanese METI-acaricide-resistant reference strain. Levels of resistance remained stable without further selection, and selection with tebufenpyrad did not increase them. The UK strain was also resistant (c 6-fold) to bifenthrin. Crosses of homozygous, diploid females with hemizygous, haploid males showed that, in the UK strain, METI-acaricide resistance was paternally and maternally inherited, and was an incompletely dominant trait. Another tebufenpyrad-resistant strain from the UK, originating fi om a chrysanthemum nursery (Chrysanthemum foeniculaceum Giseke; Asteraceae) was collected eight months later at a site c 210 km distant from the first. These are the first published incidences of METI-acaricide resistance in Europe and implications for the future use of these compounds are discussed. (C) 2000 Society of Chemical Industry.

Chemical, biological and integrated programmes for the control of two-spotted spider mite, Tetranychus urticae, were compared on dwarf hops in 1997 and 1998. In both years integrated control, which consisted of an application of the ovicidal acaricide clofentezine followed by a release of the predatory mite Phytoseiulus persimilis at 10 individuals per plant, was the most effective treatment. Similar numbers of spider mites were recorded on plots that were treated with P. persimilis only or with a single application of the acaricide tebufenpyrad, and plots with either of these treatments had higher levels of infestation than the plots under integrated control. The highest numbers of spider mites were found on the untreated plots. This study indicates that integrated control of T. urticae using clofentezine in conjunction with P. persimilis is likely to be more effective than an approach based on chemical or biological measures only. It is suggested that an integrated system would have the added benefit ov...

The toxicity of the pyrazole acaricide tebufenpyrad to the twospotted spider mite, Tetranychus urticae Koch, and the predatory mite Amblyseius womersleyi Schicha was evaluated in laboratory and field studies. In a laboratory study with the susceptible T. urticae, tebufenpyrad was highly effective against eggs, immatures (larvae and protonymphs), and adults at 25 ppm (100% mortality). Moderate levels of resistance to tebufenpyrad were observed in dicofol-resistant DR-20 (resistance ratio, 15-fold), fenpyroximate-resistant FR-20 (24-fold), and pyridaben-resistant PR-20 strains (33-fold), indicating a careful use of this acaricide on apple orchards. Additionally, tebufenpyrad had no repellent activity against either adults or immatures of the susceptible and resistant T. urticae. In 1995 and 1996 field studies of a population of T. urticae, efficacy of tebefenpyrad, expressed as a protective value at 15 or 20 d in each treated plot relative to an untreated plot, was similar to that of the commonly used azocyclotin and fenazaquin. In the laboratory and field studies with A. womersleyi, tebufenpyrad exhibited adverse effects, but this predatory mite species was more tolerant than T. urticae: 2.8, 82.2, and 46.6% mortalities against eggs, immatures, and adults at 25 ppm, respectively. No phytotoxicity was observed with this acaricide in 17-yr-old ‘Fuji’ and 11-yr-old ‘Tsugaru’ apple trees. Based on laboratory and field data, tebufenpyrad may be used to prevent damage by T. urticae and in alteration with the earlier types of acaricides in a resistance management program if a properly timed tebufenpyrad treatment is done.

A gas chromatography-mass-selective (GC-MS) detection method to determine buprofezin, pyridaben, and tebufenpyrad on the pulp, peel, and whole fruit of clementines is described. The extraction/partition procedure was performed in one step and no cleanup was necessary with the GC-MS in the SIM-mode pesticide determination. Recovery ranged from 75 to 124% with coefficients of variance ranging between 1 and 13%. The limit of determination was 0.01 mg/kg for all pesticides. The field trials showed a similar degradative behavior for all active ingredients (AI), with a great residue decrease during the first week and stability in the second. Just after treatment buprofezin and tebufenpyrad showed lower residues than the maximum residue limit (MRL) fixed in Italy, while pyridaben was below the MRL after a week.

The genetics of resistance to three new types of acaricide tebufenpyrad, fenpyroximate and pyridaben was studied by crossing a resistant (R) with a susceptible (S) strain of Tetranychus kanzawai Kishida. The resistance ratios calculated from the LC50s of the R and S strains were 97, 1265 and 134 for tebufenpyrad, fenpyroximate and pyridaben, respectively. The responses to the three acaricides in F1 females from reciprocal crosses between the R and S strains showed that the modes of inheritance of resistance to tebufenpyrad, fenpyroximate and pyridaben were intermediate, incompletely dominant and completely recessive, respectively. Furthermore, the responses of F2 females from the reciprocal crosses indicated that the resistance to the three acaricides was under monogenic control.

A strain (WA) of Tetranychus urticae Koch was collected from apples in Western Australia following a reported field-control failure of tebufenpyrad. The WA strain had been exposed to five tebufenpyrad applications over four seasons. The tebufenpyrad resistance in the WA strain was confirmed at 63.29× which is the first reported instance of tebufenpyrad resistance in T. urticae. The tebufenpyrad resistance in T. urticae conferred a >210× cross-resistance to pryidaben, a 24.60× cross-resistance to fenpyroximate and a 2.20× cross-resistance to chlorfenapyr.Exp Appl Acarol 22: 633–641 © 1998 Kluwer Academic Publishers

In aquatic ecosystems, mixtures of chemical and natural stressors can occur which may significantly complicate risk assessment approaches. Here, we show that effects of binary combinations of four different insecticides and Microcystis aeruginosa, a toxic cyanobacteria, on Daphnia pulex exhibited distinct interaction patterns. Combinations with chlorpyrifos and tetradifon caused non-interactive effects, tebufenpyrad caused an antagonistic interaction and fenoyxcarb yielded patterns that depended on the reference model used (i.e. synergistic with independent action, additive with concentration addition). Our results demonstrate that interactive effects cannot be generalised across different insecticides, not even for those targeting the same biological pathway (i.e. tebufenpyrad and tetradifon both target oxidative phosphorylation). Also, the concentration addition reference model provided conservative predictions of effects in all investigated combinations for risk assessment. These predictions could, in absence of a full mechanistic understanding, provide a meaningful solution for managing water quality in systems impacted by both insecticides and cyanobacterial blooms.

An effective method was developed and applied to determine the residues of ten pesticides of pyrazoles and pyrroles in tea by accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry (ASE-GC-MS/MS). The samples were extracted with ethyl acetate-hexane (1:1, v/v) for 5 min at 1.03 x 10(7) Pa and 100 degree C for one cycle. Then, they were purified by Envi-Carb/PSA column, and eluted by ethyl acetate-hexane (1:1, v/v). The analytes were determined by GC-MS/MS and quantified by external standard method. The limits of quantification were 0.003 mg/kg for fenpyroximate, 0.001 mg/kg for fipronil-sulfide, 0.002 mg/kg for fipronil, 0.005 mg/kg for fipronil-sulfone, 0.002 mg/kg for chlorfenapyr, 0.006 mg/kg for flusilazole, 0.001 mg/kg for difenzoquat, 0.001 mg/kg for pyraflufen-ethyl, 0.000 3 mg/kg for tebufenpyrad and 0.005 mg/kg for tolfenpyrad. The results show that the proposed method is sensitive and accurate for the determination of the ten pesticide residues.