Elimite
Attractancy and toxicity of an attracticide for Indianmeal moth, Plodia interpunctella (Lepidoptera: Pyralidae).

Nansen C, Phillips TW.

Department of Entomology, Leon Johnson Hall, Montana State University, Bozeman, PO Box 173020, MO 59717, USA. cnansen montana.edu

Plodia interpunctella (Hubner) is a serious and widespread postharvest pest on cereal products, dried fruits, candy, and pet food. Due to the strong positive anemotactic flight response of P. interpunctella males to the main component of the female-produced pheromone [(Z,E)-9,12-tetradecadienyl acetate, herein referred to as ZETA], we evaluated the potential of an attracticide for this pest, in which ZETA as attractant was combined with permethrin as the killing agent. Two concentrations of ZETA [0.16 and 0.32% (wt:wt)] and five concentrations of permethrin [0, 3, 6, 12, and 18% (wt:wt)] were incorporated into Last Call gel (10 different permethrin:ZETA combinations). All attracticide gels were evaluated in a toxicity test, in which either the tip of a leg or an antenna of a virgin P. interpunctella male was touched < 3 s into a dot of attracticide gel. These males were subsequently transferred to jars with virgin females. The toxicity test showed that a brief and gentle contact of P. interpunctella males with attracticide gel containing 3-18% permethrin caused a significant reduction in mating and killed males moths within 24 h. A wind tunnel test was conducted to evaluate the flight responses of P. interpunctella males to the same 10 attracticide gels. Male moths displayed significantly higher levels of positive anemotactic flight and more males made contact with the attracticide gel when the ZETA concentration was 0.16% compared with 0.32%. P. interpunctella males showed no signs of repellency to permethrin concentrations within a range of 0-18% in the attracticide gel. Three densities of P. interpunctella pairs were released into small warehouse rooms, and we found that the attracticide gel suppressed oviposition when the moth density was at a low level, but it was ineffective when the moth density exceeded one male-female pair per 11.3 m3.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15154501&dopt=Abstract permethrin Elimite



Elimite
Adsorption, desorption, and mobility of permethrin in Malaysian soils.

Ismail BS, Kalithasan K.

School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia. ismail pkrisc.cc.ukm.my

The adsorption, desorption, and mobility of permethrin in six tropical soils was determined under laboratory and greenhouse conditions. The six soils were selected from vegetable growing areas in Malaysia. Soil organic matter (OM) was positively correlated (r2 = 0.97) with the adsorption of permethrin. The two soils, namely, Teringkap 1 and Lating series with the highest OM (3.2 and 2.9%) released 32.5 and 30.8% of the adsorbed permethrin after four consecutive repetitions of the desorption process, respectively, compared to approximately 75.4% of the Gunung Berinchang soil with the lowest OM (1.0%) under the same conditions. The mobility of permethrin down the soil column was inversely correlated to the organic matter content of the soil. Permethrin residue penetrated only to the 10-15 cm zone in the Teringkap 1 soil with 3.2% OM but penetrated to a depth of more than 20 cm in the other soils. The Berinchang series soil with the lowest OM (1.0%) yielded leachate with 14.8% permethrin, the highest level in leachates from all the soils tested. Therefore, the possibility for permethrin to contaminate underground water may be greater in the presence of low organic matter content, which subsequently allows a higher percentage of permethrin to move downwards through the soil column.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15186031&dopt=Abstract permethrin Elimite



Elimite
Experimental hut comparisons of nets treated with carbamate or pyrethroid insecticides, washed or unwashed, against pyrethroid-resistant mosquitoes.

Asidi AN, N'Guessan R, Hutchinson RA, Traore-Lamizana M, Carnevale P, Curtis CF.

Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, UK. alex.asidi lshtm.ac.uk

The efficacy against mosquitoes (Diptera: Culicidae) of a bednet treated with carbamate insecticide [carbosulfan capsule suspension (CS) 200 mg/m(2)] was compared with four types of pyrethroid-treated nets in veranda-trap huts at Yaokoffikro near Bouake, Cote d'Ivoire, where the malaria vector Anopheles gambiae Giles carries the kdr gene (conferring pyrethroid resistance) at high frequency and Culex quinquefasciatus Say is also pyrethroid resistant. Pyrethroids compared were lambdacyhalothrin CS 18 mg/m(2), alphacypermethrin water dispersible granules (WG) 20 mg/m(2), deltamethrin 50 mg/m(2) (Permanet) and permethrin emulsifiable concentrate (EC) 500 mg/m(2). Insecticidal power and personal protection from mosquito bites were assessed before and after the nets were used for 8 months and hand washed five times in cold soapy water. Before washing, all treatments except permethrin significantly reduced blood-feeding and all had significant insecticidal activity against An. gambiae. The carbosulfan net gave significantly higher killing of An. gambiae than all pyrethroid treatments except the Permanet. Against Culex spp., carbosulfan was more insecticidal and gave a significantly better protective effect than any of the pyrethroid treatments. After washing, treated nets retained various degrees of efficacy against both mosquito genera - but least for the carbosulfan net. Washed nets with three types of pyrethroid treatment (alphacypermethrin, lambdacyhalothrin, permethrin) gave significantly higher mortality rates of Culex than in huts with the same pyrethroid-treated nets before washing. After five washes, the Permanet, which is sold as a long-lasting insecticidal product, performed no better than the other nets in our experimental conditions.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15189238&dopt=Abstract permethrin Elimite



Elimite
Solid-phase microextraction (SPME) of permethrin residues from cucumber using a silica-bonded phase-coated stainless steel fibre.

Noroozian E, Kazemipour M, Tehrani MS, Mahmoudian M.

Department of Chemistry, Faculty of Sciences, Shahid Bahoonar University, Kerman, Iran.

Solid-phase microextraction (SPME) is a rapid, economic and solvent-free sample preparation method for the isolation of an analyte from its matrix. The technique uses a few centimetres of some adsorptive materials such as activated charcoal, polydimethylsiloxane or octadecyl silane coated onto fused silica optical fibres or, more recently, stainless steel fibres mounted into a microsyringe. The proposed method allows the extraction of permethrin from cucumber matrix into the coating, avoiding sample handling and saving evaporation of solvents and concentration steps. Adsorbed permethrin was desorbed in the split/splitless injection port of the gas chromatograph. The time required for each run was about 1.5 h, which gave a preconcentration of several orders of magnitude. The method could separate and quantify cis- and trans-isomers of permethrin. The calibration curve showed linearity in the range 1-9 micrograms ml-1, with detection limits of 0.03 and 0.05 microgram ml-1 for the cis- and trans-isomers of permethrin, respectively. The method had a recovery rate of about 70% and a relative standard deviation of less than 13%. Results suggest that this procedure provides a rapid and sensitive alternative method to those currently available.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15195470&dopt=Abstract permethrin Elimite



Elimite
Resistance to insecticides and effect of synergists on permethrin toxicity in Pediculus capitis (Anoplura: Pediculidae) from Buenos Aires.

Picollo MI, Vassena CV, Mougabure Cueto GA, Vernetti M, Zerba EN.

Centro de Investigaciones de Plagas e Insecticidas (CITEFA-CONICET), Provincia de Buenos Aires, Argentina.

Permethrin-resistant colonies of Pediculus capitis (De Geer) from Buenos Aires were used to establish a resistance profile and to examine resistance mechanisms. All permethrin-resistant head lice (resistance ratio from 52.8 to > 88.7) were also resistant to d-phenothrin (resistance ratio from 40.86 to > 48.39) and deltamethrin (resistance ratio from 16.24 to 38.06). No cross-resistance to carbaryl was found in any of the pyrethroid-resistant P. capitis tested. Otherwise, all resistant colonies showed low to high levels of resistance to beta-cypermethrin. This pyrethroid had never been applied as a pediculicide in Argentina; however, the high level of resistance found in these permethrin-resistant colonies (resistance ratio from 9.74 to 50.97) demonstrated that pyrethroid cross-resistance occurred to this novel insecticide. Treatment with piperonyl butoxide (PBO) or triphenylphosphate (TPP) significantly decreased the toxicity of permethrin in the four colonies tested. The esterase inhibitor TPP produced lower enhancement of toxicity than the multifunction oxidase inhibitor PBO in the colonies having the highest resistance levels. Results presented here concerning the cross-resistance profile and synergism by enzyme inhibitors in permethrin-resistant head lice demonstrated that enhanced metabolism was involved in the pyrethroid resistance. However, the substantial degree of resistance that remained after synergism suggested the presence of another resistance mechanism. Cross-resistance to pyrethroid and susceptibility to the carbamate carbaryl suggested a common action mechanism.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11004784&dopt=Abstract permethrin Elimite