Fluvalinate Research Articles

Cyclodextrin-enhanced photo-induced fluorescence of tau-fluvalinate, molecular modelling of inclusion complexes and determination in natural waters.

The effect of adding organized supramolecular systems such as β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) on the photochemically-induced fluorescence (PIF) spectral properties of tau-fluvalinate (TFV) in aqueous solutions was examined. The influence of pH, UV irradiation time and photoproduct stability on the cyclodextrin-enhanced photochemically-induced fluorescence intensity was also investigated. The spectral changes associated with the inclusion process yielded values for the formation constants of TFV inclusion complexes between 450 and 640 M-1, which were calculated using the nonlinear iterative regression approach least squares. In addition, host-guest interaction was clearly determined by PIF enhancement and a 1 : 1 stoichiometry was found for the β-CD and HP-β-CD complexes formed with TFV. The negative free energy (ΔG°) value indicated that the reaction of TFV with cyclodextrins was thermodynamically favorable. Furthermore, the structures of inclusion complexes of TFV with cyclodextrins were elucidated by 3-21G ab initio calculations. The limits of detection and quantification obtained ranged between 1.3 and 4.0 ng mL-1 and from 4.4 to 13.0 ng mL-1 in β-CD and HP-β-CD media, respectively. The analytical application in tap and river water samples yielded satisfactory mean recoveries ranging from 98.12 to 102.97%. Due to its sensitivity and ease of use, this method can be reliably applied to routine analysis.

Cognitive impairment caused by abdominal exposure with fluvalinate in the Western honey bee, Apis mellifera

tau–Fluvalinate (fluvalinate) is a commonly used miticide (Varroa destructor), the major driver of colony collapse disorder (CCD), in the apicultural industry. Despite the relatively high tolerance of honey bees to this miticide, recent studies showed several adverse effects. The side effect on cognitive abilities, however, remains still elusive. Here, we aimed to investigate the effects of fluvalinate on the cognitive abilities of honey bees, especially associative learning, and memory. We tested the proboscis extension response (PER) to sugar taste and Pavlovian conditioning in forager bees that received a sub-lethal dose of fluvalinate on the abdomen. The current study demonstrated that sub-lethal fluvalinate induced cognitive impairment in bees. Furthermore, the comparison of gene expression patterns showed that this disorder was caused by changes in the energy metabolism associated with the subsets of specific neuropeptides that are indirectly involved in detoxification processes. Taken together, our findings are strong evidence that xenobiotics affect sensory cognition through indirect effects as well as direct damage. It might be applicable as a novel approach to exploring the mechanisms underlying the side effects of xenobiotics in various organisms.

Deciphering the groove binding modes of tau-fluvalinate and flumethrin with calf thymus DNA

Tau-fluvalinate (TFL) and flumethrin (FL), widely used in agriculture and a class of synthetic pyrethroid pesticides with a similar structure, may cause a potential security risk. Herein, the modes of binding in vitro of TFL and FL with calf thymus DNA (ctDNA) were characterized by fluorescence, UV–vis absorption, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy with the aid of viscosity measurements, melting analyses and molecular docking studies. The fluorescence titration indicated that both TFL and FL bound to ctDNA forming complexes through hydrogen bonding and van der Waals forces. The binding constants of TFL and FL with ctDNA were in the range of 104Lmol−1, and FL exhibited a higher binding propensity than TFL. The iodide quenching effect, single/double-stranded DNA effects, and ctDNA melting and viscosity measurements demonstrated that the binding of both TFL and FL to ctDNA was groove mode. The FT-IR analyses suggested the A–T region of the minor groove of ctDNA as the preferential binding for TFL and FL, which was confirmed by the displacement assays with Hoechst 33258 probe, and the molecular docking visualized the specific binding. The changes in CD spectra indicated that both FL and TFL induced the perturbation on the base stacking and helicity of B-DNA, but the disturbance caused by FL was more obvious. Gel electrophoresis analyses indicated that both TFL and FL did not cause significant DNA cleavage. This study provides novel insights into the binding properties of TFL/FL with ctDNA and its toxic mechanisms.

Stereoselective Separation and Acute Toxicity of Tau-Fluvalinate to Zebrafish

Tau-fluvalinate (TFLV) is one of the most potent chiral synthetic pyrethroids to control a wide range of pests in agricultural fields, especially in apiary. In this study, two stereoisomers of TFLV were fully separated by high-performance liquid chromatography (HPLC) with a semipreparative chiral column using cellulose-tris(3,5-dimethylphenylcarbamate) as chiral stationary phase andn-hexane and 2-propanol (96/4, v/v) as mobile phase at a flow rate of 2.5 mL min−1. The (+)-stereoisomer was first eluted by detecting with an optical rotation detector. After obtaining pure single stereoisomer of TFLV, acute toxicities of each isomer and TFLV standard to zebrafish were evaluated. The results showed that the (+)-stereoisomer exhibited 273.4 times higher toxicity than the (−)-stereoisomer and 6.7 times higher than TFLV standard, according to their LC50values at 96 h after exposure. This indicates that the toxicity of TFLV mainly originates from (+)-stereoisomer. These results are very helpful to prepare single stereoisomer of chiral pesticides and evaluate their different toxicological effects to aquatic organisms.

Field-Level Sublethal Effects of Approved Bee Hive Chemicals on Honey Bees (Apis mellifera L)

In a study replicated across two states and two years, we tested the sublethal effects on honey bees of the miticides Apistan (tau fluvalinate) and Check Mite+ (coumaphos) and the wood preservative copper naphthenate applied at label rates in field conditions. A continuous covariate, a colony Varroa mite index, helped us disambiguate the effects of the chemicals on bees while adjusting for a presumed benefit of controlling mites. Mite levels in colonies treated with Apistan or Check Mite+ were not different from levels in non-treated controls. Experimental chemicals significantly decreased 3-day brood survivorship and increased construction of queen supercedure cells compared to non-treated controls. Bees exposed to Check Mite+ as immatures had higher legacy mortality as adults relative to non-treated controls, whereas bees exposed to Apistan had improved legacy mortality relative to non-treated controls. Relative to non-treated controls, Check Mite+ increased adult emergence weight. Although there was a treatment effect on a test of associative learning, it was not possible to statistically separate the treatment means, but bees treated with Apistan performed comparatively well. And finally, there were no detected effects of bee hive chemical on colony bee population, amount of brood, amount of honey, foraging rate, time required for marked released bees to return to their nest, percentage of released bees that return to the nest, and colony Nosema spore loads. To our knowledge, this is the first study to examine sublethal effects of bee hive chemicals applied at label rates under field conditions while disambiguating the results from mite control benefits realized from the chemicals. Given the poor performance of the miticides at reducing mites and their inconsistent effects on the host, these results defend the use of bee health management practices that minimize use of exotic hive chemicals.

Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures. Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferase reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [(3)H](2)O method. Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity. In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks.

Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures.Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferase reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [3H]2O method.Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity.In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks.

Identification of mutations associated with pyrethroid resistance in the voltage-gated sodium channel of the tomato leaf miner (Tuta absoluta)

The tomato leaf miner, Tuta absoluta (Lepidoptera) is a significant pest of tomatoes that has undergone a rapid expansion in its range during the past six years and is now present across Europe, North Africa and parts of Asia. One of the main means of controlling this pest is through the use of chemical insecticides. In the current study insecticide bioassays were used to determine the susceptibility of five T. absoluta strains established from field collections from Europe and Brazil to pyrethroids. High levels of resistance to λ cyhalothrin and tau fluvalinate were observed in all five strains tested. To investigate whether pyrethroid resistance was mediated by mutation of the para-type sodium channel in T. absoluta the IIS4–IIS6 region of the para gene, which contains many of the mutation sites previously shown to confer knock down (kdr)-type resistance to pyrethroids across a range of different arthropod species, was cloned and sequenced. This revealed that three kdr/super-kdr-type mutations (M918T, T929I and L1014F), were present at high frequencies within all five resistant strains at known resistance ‘hot-spots’. This is the first description of these mutations together in any insect population. High-throughput DNA-based diagnostic assays were developed and used to assess the prevalence of these mutations in 27 field strains from 12 countries. Overall mutant allele frequencies were high (L1014F 0.98, M918T 0.35, T929I 0.60) and remarkably no individual was observed that did not carry kdr in combination with either M918T or T929I. The presence of these mutations at high frequency in T. absoluta populations across much of its range suggests pyrethroids are likely to be ineffective for control and supports the idea that the rapid expansion of this species over the last six years may be in part mediated by the resistance of this pest to chemical insecticides.

Acaricides determination from honey through GC-MS technique using different extraction methods.

Honey was subjected to GC-MS analysis in order to identify and quantify acaricides residues (2,4-dimethylaniline, brompropilate, amitraz, coumaphos, fluvalinate). Two rapid methods were compared for the extraction and purification of acaricides from honey. First method uses as extraction solvent acetonitrile in the presence of high quantities of salts, which underwent a clean up step known like dispersive solid-phase extraction dSPE PSA (QuEChERS method). In the second method the acaricides were eluted with dichloromethane from the mixture of the sample with diatomaceous earth. Both methods offered the extraction of all mentioned acaricides, but the second one offered higher recoveries, lower costs and was less time consuming for sample preparation. LOD for all acaricides ranged from 0.8-8.3 I¼g/kg and for LOQ between 1 and 9.7 I¼g/kg. Higher recovery rates (90 - 108%) were obtained when sample preparation involved diatomaceous earth.Â

RESIDUOS DE TAU FLUVALINATO (PIRETROIDE) EN LA CERA DE LA CÁMARA DE CRÍA Y SU EFECTO SOBRE LARVAS DE ABEJAS DE LA CASTA OBRERA (Apis mellifera L.)

Since the application of tau fluvalinate to control Varroa destructor Anderson & Trueman negatively affects larvae of A. mellifera, an study was carried out to measure the damage caused by the residual presence of the chemical in the beeswax of the breeding chamber in the development of working bees larvae. First, third and fifth instars larvae were studied using three treatments (concentrations of 8, 12 and 18 ppm of the chemical) and a control (0 ppm) in Langstroth hives waxes located at the Austral University of Chile facilities (Los Rios region). Every fifth frame of the breeding chamber was replaced with a treated one. The parameters used for evaluation where weight, size, color, scent, mortality and the final concentration of fluvalinate in beeswax. It was determined that tau fluvalinate affects the normal larval development regarding weight and size in the three stages; in both cases the fifth stage was more affected with the concentration of 18 ppm, showing less than 17.8% of the normal weight and less than 12.2% of the normal size. The color, odor and mortality of the larvae were not affected by the chemical in any of the concentrations used, therefore the LD50 of this product, for working bees, is higher than 18 ppm.. The concentration of tau fluvalinate in the wax decreased in 93% which could be caused by the dilution of the product due to wax stretching.

Determination of pyrethroid pesticide residues in processed fruits and vegetables by gas chromatography with electron capture and mass spectrometric detection.

A gas chromatographic method was developed for the simultaneous determination of 12 pyrethroids (tefluthrin, bifenthrin, fenpropathrin, cyhalothrin, permethrin, cyfluthrin, cypermethrin, alpha-cypermethrin, flucythrinate, fenvalerate, fluvalinate, and deltamethrin) in tomato puree, peach nectar, orange juice, and canned peas. A miniaturized extraction-partition procedure requiring small amounts of nonchlorinated solvents is used. Samples are extracted with acetone, partitioned with ethyl acetate-cyclohexane (50 + 50, v/v), and cleaned up on a Florisil cartridge. The final extract is analyzed by gas chromatography with both electron capture and mass spectrometric detection modes. Studies at fortification levels of 0.010-0.100 mg/kg gave mean recoveries ranging from 70.2 to 96.0% and coefficients of variation between 4.0 and 13.9% for all compounds. Quantitation limits were < 0.010 mg/kg for electron capture detection.

The effect of Apistan® on honey bee (Apis mellifera L). Responses to methyl parathion, carbaryl and bifenthrin exposure

Cette etude visait a determiner si le traitement a l'Apistan® augmentait la vulnerabilite des abeilles a trois insecticides, utilises couramment en protection des cultures. Les tests biologiques ont ete faits sur 720 abeilles adultes prelevees dans une meme colonie pour chacun des trois insecticides etudies. Les abeilles ont ete placees dans des cages d'expedition de Benton a raison de dix abeilles par cage. Les cages ont ete divisees en deux groupes: une moitie a recu les inserts Apistan Queen Tabs®, l'autre n'a pas ete traitee. Des dilutions en serie de bifenthrine (pyrethrinoide), de carbaryl (carbamate) et de parathion-methyl (organophosphore) ont ete administrees aux abeilles avec une micro-seringue Hamilton, a raison de de 0,5 μL par abeille. L'acetone a ete utilisee comme solvant et des temoins traites a l'acetone ont ete inclus dans chaque test. Six repetitions de dix abeilles ont ete faites pour chacune des doses d'insecticide pour le lot traite a l'Apistan® et autant pour le lot non traite. La mortalite a ete evaluee 24 h apres le traitement, les donnees ont ete analysees par la methode Probit a l'aide du logiciel POLO. Les DL 50 avec des intervalles de confiance qui ne se chevauchent pas ont ete considerees comme significativement differentes. Tous les taux de synergie ont ete significatifs au seuil de probabilite de 95 %; neanmoins, ils n'avaient de valeur que si les DL 50 comparees etaient significativement differentes. Les abeilles traitees a l'Apistan® ont montre une sensibilite plus grande a la bifenthrine que les non traitees (tableau I). Mais la sensibilite des colonies au carbaryl et au parathion-methyl ne semble pas etre affectee par une exposition prealable a l'Apistan®. La bifenthrine a ete 1,9 fois plus toxique pour les abeilles traitees que pour les non traitees. Les DL 50 calculees pour le carbaryl et le parathion-methyl sont respectivement 1,4 et 1,1 fois plus elevees pour les abeilles non traitees, mais les differences ne sont pas significatives. Le resultat le plus interessant est que l'Apistan® n'a eu d'action importante sur la toxicite d'aucun des trois insecticides testes. Meme si l'effet concernant la bifenthrine est significatif, la difference est faible et il est difficile d'extrapoler aux conditions de plein champ. Neanmoins, par precaution, les apiculteurs devraient eviter de traiter leurs colonies a l'Apistan® pendant les periodes ou les abeilles sont susceptibles de butiner des cultures traitees a la bifenthrine.

Thrip control with fluvalinate on kiwifruit

Thrip control with fluvalinate on kiwifruit

Applicator exposure to fluvalinate, chlorpyrifos, captan, and chlorothalonil in Florida ornamentals

Applicator exposure to fluvalinate, chlorpyrifos, captan, and chlorothalonil in Florida ornamentals

Thrips control on nerine flowers with fluvalinate

Thrips control on nerine flowers with fluvalinate

Thrips control on stonefruit at harvest with fluvalinate

Thrips control on stonefruit at harvest with fluvalinate

Effect of Pyrethroids on Knockdown and Lack of Coordination Responses of Susceptible and Resistant Diamondback Moth (Lepidoptera: Plutellidae)

Among DDT and the 10 pyrethroids tested, permethrin, cypermethrin, deltamethrin, and fenvalerate were most toxic against a field strain of Plutella xylostella (L.) that had high levels of resistance to all insecticides tested. Knockdown effect of these compounds against larvae and adults of susceptible and resistant strains was evaluated by a residual-film method. Symptoms of poisoning are described. When larvae or adults could no longer stand and had to lie on their sides, they were considered knocked down. Pyrethroids with primary alcohol esters produced more acute symptoms than those with secondary alcohol esters. Responses of resistant larvae and adults were less pronounced than those of susceptible ones. In the resistant strain, addition of synergist piperonyl butoxide (PB) to the pyrethroids produced symptoms displayed by the susceptible strain. Tetramethrin, which was not highly toxic, was the most potent knockdown agent against susceptible larvae. Knockdown action of all pyrethroids appeared much more slowly in resistant larvae; fluvalin ate and flucythrinate were least effective as knockdown as well as killing agents. Addition of synergists PB, S,S,S-tributyl phosphorotrithioate, and chlordimeform generally enhanced knockdown action of most pyrethroids in resistant larvae, but had only limited effect in susceptible larvae. Maximal knockdown of adults by fenvalerate was reached 60–90 min after exposure; PB synergized this action of fenvalerate and reduced recovery of the moths within 24 h.

Photodegradation of fluvalinate

Photodegradation of fluvalinate

Metabolism of [benzyl-U-ring-14C]fluvalinate by rats

Metabolism of [benzyl-U-ring-14C]fluvalinate by rats

Degradation and movement of fluvalinate in soil

Degradation and movement of fluvalinate in soil