Vol. 6, Issue 2, Part A (2019)

Author(s): Mahboob Ghamari, Mehdi Khoobdel and Maryam Iman

Abstract: Permethrin-impregnated cloths and uniforms are one of the most effective personal protection measures against a variety of vector arthropods. Today, the dipping method with commercially available permethrin emulsions is a common method to impregnation of fabrics. But these formulations suffered from low durability on fabrics. In this regard, technical permethrin was formulated to permethrin solution (Emulsion), polymeric and microencapsulated formulations and their residual persistency was measured chromatographically on military uniform fabrics. Additionally, impregnated-fabrics efficacy on the knockdown and mortality were evaluated against Anopheles stephensi L. (Diptera: Culicidae). The obtained results showed markedly higher residual permethrin quantities with the polymeric and microencapsulated formulation, resulting in 237 and 124 mg/m² still present after 50 defined launderings, respectively. The knockdown and mortality rates of A. stephensi after 10 and 20 launderings, respectively, were significantly higher (P<0.05) for mosquitoes exposed to the polymeric and microcapsule formulations. The evaluation of the laundering-dependent time frame for obtaining 100% knockdown of mosquitoes constantly exposed to permethrin-impregnated fabrics indicated that 100% knockdown time of A. stephensi ranging from 3.5 min, 4.2 min and 4.1 min, prior to laundering, respectively. After 50 launderings, 100% knockdown time was > 120 min, 28.6 min and 45.8 min, for permethrin solution, polymeric and microcapsule formulations, respectively. These findings confirm the incremental impact of polymeric and microcapsule formulations on permethrin persistency and residual activity on fabrics against A. stephensi.

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