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1.
Permethrin was metabolised by attack at the ester bond, in vivo by adult cockroaches, Periplaneta americana and in vitro by esterase preparations. Metabolites retaining the ester linkage could not be detected. In all cases, the (1RS)-trans-isomer (transpermethrin) was more labile than the (1RS)-cis-isomer. Cypermethrin was metabolised at one-fifth the rate for permethrin. In-vitro and in-vivo studies with synergists indicated that cleavage of the ester bond in permethrin can be both oxidative for the (1RS)-cis-isomer and hydrolytic for the (1RS)-trans-isomer. The penetration of permethrin through the cuticle of the cockroach was significantly greater than that of cypermethrin. The penetration and metabolism of permethrin and cypermethrin in sixth-instar larvae of susceptible and resistant strains of the Egyptian cotton-leafworm, Spodoptera littoralis, were studied as possible factors in resistance. No significant differences were found. It is suggested that the major resistance factor to permethrin in S. littoralis is probably non-metabolic.  相似文献   

2.
The action of cis-permethrin, which evinced a strong negative correlation of toxicity with temperature in larvae of the pyrethroid-susceptible Yeerongpilly and pyrethroid-resistant DDT-R and Malchi strains of the cattle tick, was accounted for by a simple binding mechanism. The mechanism assumed that a single pyrethroid molecule binds to a single site and inactivates it, and that the equilibrium constant which describes the ensuing equilibrium between concentrations of free pyrethroid, unoccupied site, and inactivated site then varies with temperature according to the van't Hoff equation. From van't Hoff plots of the data the enthalpies of binding of cis-permethrin to sites in larvae of each of the above strains were calculated to be ?87, ?92, and ?102 kJ mol?1, respectively. It was concluded from these results that the kdr-type insensitivity (≈6×, in terms of resistance) observed in DDT-R and Malchi ticks could not be explained by altered binding sites at the site of action. It was suggested that the insensitivity might be explained by altered access to the site of action.  相似文献   

3.
Observations suggest that more than one mechanism is responsible for the increased tolerance to permethrin in the larval stage of Lucilia sericata. While the penetration rate of permethrin was much reduced in larvae, they remained more tolerant than adults when this compound was injected. Following the injection of sublethal amounts of [3H]-(1 RS)-trans-permethrin, a substantial proportion of the dose was accumulated and retained in the larval fat body. In adults, less permethrin was absorbed and retained in the tissues. However, compared to the larvae, detoxication was faster, haemoplasm levels were lower, and substantially more breakdown products were excreted. The injection of sublethal amounts of permethrin into the larva led to severe disruption of sensory function. These findings suggest that an important difference may exist between adults and larvae in either the sensitivity of vital sites within the nervous system, or in the sequence of events which follow nervous system disruption and lead to death.  相似文献   

4.
Sugar beet, wheat, lettuce and cotton were grown in soil treated with [14C]permethrin, the crops being sown at intervals of 30, 60 and 120 days after treatment of the soil. The uptake of radioactive residues into these crops was measured. Low radioactive residues (up to 0.86 μg g?1) were detected in the mature plants sown 30 days after soil treatment, and this uptake declined significantly as the interval between soil treatment and sowing increased. Metabolites derived from the acid moiety of the permethrin molecule were shown to constitute the greater part of the residue transferring from the soil to the crops. (1RS)-cis- and (1RS)-trans-3-(2,2-dichlorovinyl)- 2,2-dimethylcyclopropanecarboxylic acid and 3-(2,2-dichlorovinyl)-1-methylcyclopropane-1,2-dicarboxylic acid were identified as the major acidic metabolites. The latter compound is a metabolite of permethrin which has not previously been identified in soil or plants.  相似文献   

5.
The effect of droplet diameter (36-274 μm) and concentration (10-400 g litre?1) of permethrin on the knockdown and mortality of 2nd-instar Plutella xylostella larvae was investigated. Larvae were placed on brussels sprout leaf discs treated with residual deposits of permethrin applied as ULV or emulsion formulations. The LD50 of permethrin decreased with droplet size at all concentrations tested. This effect could not be accounted for solely by increased drop numbers per unit area of leaf, suggesting that for both formulations transfer of permethrin to larvae is more efficient for deposits composed of small drops. The concentration of permethrin in the ULV formulation could be reduced to approach a minimum quantity of toxicant per unit area to maintain 50 per cent mortality. The approach to the minimum dose varied with drop size and drop number per unit leaf area. The ULV formulation was approximately 2.7 times more effective at killing larvae than the emulsion, presumably as a result of greater availability of toxicant and transfer to larvae.  相似文献   

6.
The principal esterases present in homogenates of cattle tick larvae have been separated by gel filtration and preparative isoelectric focusing. Substrate specificities have been determined using trans-permethrin, trans-cypermethrin, p-nitrophenyl butyrate, and the pyrethroid analog, p-nitrophenyl-(1R,S)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate (t-NPDC). One of the esterases, with pI = 4.6, and molecular weight ～67,000, hydrolyzed the α-cyano-substituted pyrethroid, trans-cypermethrin, but not permethrin. The major esterase activity was found in the pI 5.6–5.8 region, and corresponded to a molecular weight of ～89,000. Small differences in substrate specificity and differences in the banding pattern after isoelectric focusing were detected between esterases of ticks of a pyrethroid-resistant strain (Malchi) and a pyrethroid-susceptible strain (Yeerongpilly). Rate constants were determined for the inhibition of the different esterases by the organophosphate coroxon and by naphthyl N-propylcarbamate, using p-nitrophenyl butyrate and t-NPDC as substrates.  相似文献   

7.
In May 2001 a sample of Culex pipiens pipiens variety molestus Forskål from Marin County, California, collected as larvae and reared to adults, was found to show reduced resmethrin and permethrin knock‐down responses in bottle bioassays relative to a standard susceptible Cx pipiens quinquefasciatus Say colony (CQ1). Larval susceptibility tests, using CQ1 as standard susceptible, indicated that the Marin mosquitoes had LC50 resistance ratios of 18.3 for permethrin, 12 for deltamethrin and 3.3 for pyrethrum. A colony of Marin was established and rapidly developed higher levels of resistance in a few generations after exposure to permethrin as larvae. These selected larvae were shown to cross‐resist to lambda‐cyhalothrin as well as to DDT. However, adult knock‐down time in the presence of permethrin, resmethrin and pyrethrum was not increased after increase in tolerance to pyrethroids as larvae. Partial and almost complete reversion to susceptibility as larvae was achieved with S, S, S‐tributylphosphorotrithioate and piperonyl butoxide (PBO), respectively, suggesting the presence of carboxylesterase and P450 monooxygenase mediated resistance. Insensitive target site resistance (kdr) was also detected in some Marin mosquitoes by use of an existing PCR‐based diagnostic assay designed for Cx p pipiens L mosquitoes. Carboxylesterase mediated resistance was supported by use of newly synthesized novel pyrethroid‐selective substrates in activity assays. Bottle bioassays gave underestimates of the levels of tolerance to pyrethroids of Marin mosquitoes when compared with mortality rates in field trials using registered pyrethroid adulticides with and without PBO. This study represents the first report of resistance to pyrethroids in a feral population of a mosquito species in the USA. Copyright © 2003 Society of Chemical Industry  相似文献   

8.
In laboratory studies, Colorado potato beetle (CPB) (Leptinotarsa decemlineata Say) reared on eggplant were significantly more susceptible to permethrin than CPB reared on tomato. Field studies conducted in 1984 and 1985 showed that the percentage reduction of CPB larvae reared on eggplant due to foliar applications of fenvalerate was significantly greater than the percentage reduction of CPB larvae reared on either potato or tomato. Plant defoliation was greater on eggplant and potato than on tomato. Eggplant and potato yields increased as the dose of fenvalerate increased and the potato beetle population decreased, but tomato yields were unaffected by fenvalerate treatments. The effects and biological activity of individual plant chemical compounds (i.e., glvcoalkaloids) in various Solanum species need to be examined in detail before the full significance of the role of these compounds in host-plant resistance and their interaction with CPB insecticide resistance are understood.  相似文献   

9.
Comparisons with standard susceptible insects showed that a strain of Tribolium castaneum, with a specific resistance to malathion and its carboxylic ester analogues, had no cross-resistance to topical applications of natural pyrethrins. Another strain of T. castaneum, showing resistance to many organophosphorus (OP) insecticides, was cross-resistant to pyrethrins ( × 34) and eight synthetic pyrethroids also applied topically; least cross-resistance occurred with resmethrin ( × 2.2), bioresmethrin ( × 3.3) and phenothrin ( × 4.0). Generally larger resistance factors were recorded with formulations synergised by piperonyl butoxide (PB). The greatest cross-resistance encountered was with unsynergised tetramethrin ( × 338). Apart from tetramethrin, factors of synergism did not exceed 5.7 with either the susceptible or multi-OP resistant strains. PB antagonised six of the nine pyrethroids against the multi-OP resistant strain. Antagonism also occurred with two of these six, permethrin (cis: trans ratio 1:3) and 5-prop-2-ynylfurfuryl ( 1RS)-cis,trans-chrysanthemate (‘Prothrin’), against the susceptible strain. Considering only formulations without the synergist, the most effective compounds against the susceptible strain, relative to pyrethrins, were bioresmethrin (2.7) and permethrin (2.4). Similarly with the multi-OP resistant strain the most effective compounds were bioresmethrin (28), resmethrin (14) and permethrin (6.6). Thus the LD50 (the dose required to kill 50% of the test species) for bioresmethrin against the resistant strain (0.14 μg) only slightly exceeded the LD50 for pyrethrins against the susceptible strain (0.12 μg).  相似文献   

10.
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11.
Adult Rana pipiens pipiens (Shreber) are highly sensitive to insecticidal α-cyano-3-phenoxybenzyl esters administered subcutaneously, i.e., LD50 0.13–0.35 mg/kg for deltamethrin and the most potent isomer of each of cis-cypermethrin, fenpropathrin, and fenvalerate and 0.65 mg/kg for (1R,αS)-trans-cypermethrin. Pyrethroids lacking the α-cyano substituent [pyrethrins, S-bioallethrin, kadethrin, and the Cis- and trans-isomers of (1R)-tetramethrin, (1RS)-resmethrin, (1R)-phenothrin, and (1R)-permethrin] vary greatly in their toxicity (LD50 0.14 to > 60 mg/kg) and the trans isomers are much less toxic than the corresponding cis isomers. The trans/cis specificity is due in large part to relative detoxification rates based on synergism studies with the resmethrin and permèthrin isomers and liver pyrethroid esterase assays with the permethrin and cypermethrin isomers. Poisoning by the noncyano compounds involves hyperactivity and tremors whereas by the cyanophenoxybenzyl esters involves tonic seizures and choreoathetosis, i.e., types I and II syndromes, respectively. Picrotoxinin, t-butylbicyclophosphate, and five other small cage compounds give a third type of syndrome with clonic seizures. Diazepam and its 2′-fluoro-4-methyl-4,5-dihydro analog (RO 5-3636) are more effective than 23 other compounds tested in protecting against deltamethrin toxicity. Diazepam is most effective in alleviating the Type II syndrome, intermediate with the type I syndrome, and is not active with picrotoxinin.  相似文献   

12.
Effects of two acaricides, permethrin and amitraz, with different modes of action, on gas exchange and water balance of the lone star tick, Amblyomma americanum, were examined using a flow-through carbon dioxide (CO2) and water vapor analyzer. Untreated adult female ticks exhibited a distinct discontinuous gas exchange pattern (DGEP) with no measurable water loss. Similarly, ticks with acetone (a solvent) showed little change in gas exchange and water loss. Topical treatment of ticks with a lethal dose of permethrin caused immediate major water loss and long-lasting high frequency DGEP, with increased amplitude of CO2 release. A small water loss spike was observed for each CO2 release. Treatment of ticks with amitraz abolished the DGEP and elicited a long-lasting continuous gas exchange pattern, indicating significantly increased tick metabolism. No detectable water loss was observed during amitraz-elicited continuous gas exchange. Treatment of ticks with a mixture of sub-lethal doses of permethrin and amitraz caused a similar initial major water loss, as in permethrin-treated ticks, followed by a second period of water loss activity at 10–14 h after treatment. Mixture of the two acaricides caused immediate onset of major chaotic CO2 release activities with a significantly elevated baseline CO2 emission level. The standard metabolism rate (SMR, VCO2) of acetone-treated ticks (0.452 μl h−1) was similar to that of the untreated ticks (0.461 μl h−1). Compared to untreated control ticks, permethrin-, amitraz-, and the acaricide mixture-treated ticks exhibited significantly increased SMR (1.054, 1.392 and 1.520 μl h−1 respectively (P < 0.05). Results obtained from this study clearly demonstrated the detrimental effects of permethrin and amitraz on CO2 gas exchange and water balance in A. americanum ticks. The data also revealed subtle differences between permethrin and amitraz in their effects on tick metabolism, specifically gas exchange and water loss. In addition, the study may provide insight into the modes of action of these two acaricides in tick physiology. The results may also help understand the mechanism of synergism between permethrin and amitraz that was reported previously in other ticks and insects.  相似文献   

13.
Preparation of 3-phenoxybenzyl chrysanthemates and their dihalovinyl analogues substituted with a cyano group at the 2-, 6-, (R)-α-, or (S)-α- positions is described. The (R)- and (S)- isomers of α-cyano-3-phenoxybenzyl esters of 2,2-difluoro-, -dichloro-, and -dibromo-vinyl analogues of cis- and trans- chrysanthemic acid are separated chromatographically, as are the separate pairs of enantiomers of fenvalerate, (RS)-α- cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate. An optically active ester of α-cyano-3-phenoxybenzyl alcohol (obtained using D -oxynitrilase) with 2,2,3,3-tetramethylcyclopropanecarboxylic acid is synthesised.  相似文献   

14.
Metabolism in mice of the separated cis- and trans-isomers of the pyrethroid insecticide cypermethrin (NRDC 149), (RS)-α-cyano-3-phenoxybenzyl (1RS)-cis, trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate, was investigated in each case with preparations that were 14C-labelled in the benzyl and cyclopropyl moieties. Radioactivity from the trans-isomer was mainly excreted in the urine and that from the cis-isomer in the faeces. Elimination of both isomers was rapid except for a small portion (approximately 2%) of the cis-isomer which was released from the fat with a half-life of approximately 13 days. Metabolism of cypermethrin occurred mainly by ester cleavage and elimination of the cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl- cyclopropanecarboxylic acid moieties as glucuronide conjugates. The α-cyano-3-phenoxybenzyl alcohol released by ester cleavage was mainly converted to 3-phenoxy-benzoic acid which was partly eliminated unchanged, partly conjugated with aminoacids (mainly taurine) and glucuronic acid, and partly oxidised to 3-(4-hydroxyphenoxy) benzoic acid which was excreted as the sulphate conjugate. Metabolites retaining the ester linkage were formed by hydroxylation at various sites in the molecule with more hydroxylation of the cis- than of the trans-isomer occurring.  相似文献   

15.
An antifeeding (feeding deterrent) response by first- and fifth-instar larvae of Pieris brassicae was shown to be significant at sub-lethal levels of cypermethrin and permethrin, using leaf-discs treated with the pyrethroids by dipping. Permethrin was slightly more effective than cypermethrin both as an insecticide and as an antifeedant against fifth-instar larvae, but the reverse order of effectiveness was observed, with a marked difference in mortality, against newly-hatched larvae. When 1-day-old fifth-instar larvae were continuously given leaf discs treated with a solution of the pyrethroid (1 mg litre?1), up to the time of pupation, both cypermethrin and permethrin induced a significant extension of the larval period, with a reduction in the maximum larval and pupal weights, as well as a reduction in the total leaf-area consumed. However, at higher levels of both pyrethroids, lowering the temperature induced some irritancy, as indicated by regurgitation and frequent uncoordinated wriggling movements of the fifth-instar larvae. The advantages of cypermethrin as a protectant and as an antifeedant over permethrin are discussed.  相似文献   

16.
New pyrethroids containing heterocyclic rings in the alcohol moieties were synthesised and their insecticidal activities were studied. Of these new pyrethroids, 3-benzylpyrrol-1-ylmethyl (1RS-cis, trans-3(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate was found to be the most effective, having higher activity than permethrin against Musca domestica by a topical application method. In addition, para-substituted analogues of the 3-benzylpyrrol-1-ylmethyl ester were also synthesised to study the substituent effects on insecticidal activities; the residual effects of these compounds against Blattella germanica were also examined.  相似文献   

17.
Fenvalerate and permethrin residues on hair of groups of cattle that received either two tags per adult animal or one tag for every other adult animal were determined using gas chromatography over a three-month period in 1987 and 1988. Cattle with two tags had consistently higher residues than cattle with one tag. This difference was statistically significant (P < 0.05) in the first month for residues on the head and in the first two weeks for residues from the body in 1987. Residues on cattle with one tag and without a tag in the same herd were similar (P > 0.05) on each sampling day on all regions. Residues on the hair from the head of cattle with two tags were greater than on the body and rump (P < 0.05) during the first 28 days. Residues found on hair on days 14 and 84 following tag application declined by 80–86% on the head, 73–78% on the body, and 36–86% on the rump. Isomeric compositions of fenvalerate (range 51–61% SR, RS: 39–49% SS, RR) and permethrin (range 61–67% trans: 33–39% cis) were consistent during the study. Rainfall reduced residues on hair.  相似文献   

18.
Two experimental insecticides, AC 303,630 and MK 244, were tested against a laboratory colony and three field strains of Pseudoplusia includens (Walker). Topical application bioassays indicated that permethrin resistance in the field strains ranged from 3.9 to 489.0-fold. In leaf dip bioassays, LC50 and LC90 values for AC 303,630 ranged from 6.7 to 15.1 mg litre ?1 and 8.7 to 28.2 mg litre ?1, respectively, for third-instar larvae. The Louisiana 1991 field strain was significantly more susceptible to AC 303,630 than the laboratory and other field strains. The LC50 (but not LC90) for the Louisiana 1992 field strain was significantly higher than that of the laboratory strain. However, there was no difference in toxicity of AC 303,630 between the field strain with the highest level of permethrin resistance and the laboratory strain. LC50 and LC90 values for MK 244 in leaf dip bioassays ranged from 0.014 to 0.023 mg litre ?1 and 0.079 to 0.174 mg litre ?1, respectively. There were no significant differences in LC 50 or LC 90 among any of the strains for MK 244. Field trials in soybean were also conducted in 1991 and 1992 in an area of Louisiana where permethrin efficacy against P. includens has declined. In both years, AC 303,630 at 0.11–0.22 kg ha ?1, and MK 244 at 0.0042–0.0084 kg ha ?1, provided significantly better control than permethrin at 0.11 kg ha ?1, and control equal to the recommended standard, thiodicarb. These studies indicate no cross-resistance exists between the experimental insecticides and permethrin.  相似文献   

19.
BACKGROUND: The most common ways to control dengue vector Aedes aegypti (L.) are larval source reduction in domestic habitats and ground application of small quantities of aerosol insecticide (ultralow volume). Nevertheless, these actions have been shown repeatedly to be ineffective in controlling Ae. aegypti populations. RESULTS: The efficacy of a new smoke‐generating formulation containing pyriproxyfen and permethrin was evaluated in the laboratory. Smoke‐generating tablets containing each insecticide individually or combined were prepared, and the recovery of the insecticides from the smoke was determined. Recovery values of over 90% were obtained for pyriproxyfen, and around 50% for permethrin. The biological efficacy of pyriproxyfen released in the smoke was evaluated in the laboratory, on late third‐instar or early fourth‐instar Ae. aegypti larvae, using different concentrations of pyriproxyfen and exposure times. Adult emergence inhibition (EI) values of 100% were obtained at 30 min, and a dose‐dependent effect was observed at 5 min. The effect of pyriproxyfen released in the smoke was due to direct contact with the larvicide in the water rather than by inhalation of the fumes. The efficacy of permethrin released in the fumes was also evaluated as knockdown effect (KT50) on adults for a tablet containing permethrin alone or permethrin plus pyriproxyfen. There was no significant difference in KT50 values obtained for permethrin (KT50 = 19.9 min) and permethrin plus pyriproxyfen (KT50 = 19.4 min). CONCLUSION: The excellent laboratory performance of this new formulation on immature stages and adults indicates that a smoke‐generating tablet containing pyriproxyfen and permethrin could be a new tool for controlling mosquitoes. Copyright © 2009 Society of Chemical Industry  相似文献   

20.
One or more weak factors of resistance on autosome 2, and barely detectable resistance on autosome 3, confer moderate resistance to several pyrethroids (5–13-fold) in the field-collected Ipswich strain of houseflies. In these flies, which unlike other pyrethroid-resistant strains lack kdr or super-kdr, pyrethroid resistance probably developed in response to prolonged treatment of buildings for animals with pyrethrins synergised with piperonyl butoxide. Substrains, isolated genetically from Ipswich flies and with resistance only on autosome 2, degraded permethrin more rapidly than susceptible flies and produced larger amounts of very polar metabolites. In this, they differed from flies with kdr or super-kdr which resembled susceptible flies in their metabolism of permethrin. NIA 16388 (propyl prop-2-ynyl phenylphosphonate) was a better synergist and reduced the metabolism of permethrin more than piperonyl butoxide in both the susceptible and resistant insects. The slight increase in synergism and minimal decrease in metabolism when piperonyl butoxide was applied with NIA 16388 indicated that the latter also inhibited detoxication that was sensitive to piperonyl butoxide.  相似文献   

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