Ovicidal activity of Thymus vulgaris (Labiatae) against Pediculus humanus capitis (Anoplura, Pediculidae)

GUTIÉRREZ, M.M; STEFANAZZI, N.; WERDIN GONZÁLEZ, J.O.; FERRERO, A. A.

Huerta Grande, Córdoba

Congreso; 2º Meeting of Latin American Association of Chemical Ecology; 2012

Latin American Association of Chemical Ecology

In Argentina, pediculosis is a serious health problem that affects more than 30% of school-age children. The prevalence of head lice (Pediculus humanus capitis De Geer) in kindergarten from Bahía Blanca (Province of Buenos Aires, Argentina) was 42.7% [1]. Today, essential oils (EOs) are an interesting alternative in the control of this insect. The aim of this study was to evaluate the ovicidal activity of EO from T. vulgaris. Lice were collected using metal comb from infested children 3-5 years old. The oil was obtained by hydrodistillation in a modified Clevenger type apparatus and analyzed by gas chromatography coupled to mass spectrometry (GC-MS HP5972A). The analysis revealed the presence of major components such as p-cymene (26%), g-terpinene (21.8%) and 1-terpinen-4-ol (16.3%) and minor components such as carvacrol (3.1%) and d-terpinene (3.3%). Eggs were held at 31 ± 1 ° C and 65 ± 5% RH and darkness. Filter papers (5.5 cm diameter Whatman No. 1) were treated with 100 μl of hexane solution. Four concentration were used (0.21 mg/cm2, 0.08 mg/cm2, 0.05 mg/cm2, 0.02 mg/cm2). Control filter papers received hexane alone. After solvent evaporation, filter papers were placed in the bottom of a Petri dish. Groups of 10 eggs (3-4 days old) attached to hair were placed in each Petri dish and covered with a lid. All treatments were replicated three times. After 8 days, the percentage of inhibition of hatch (PIH) was calculated from the formula PIH (%) = [(C ?T)/C] X 100, where C is the control percentage hatch and T is the treated percentage hatch [2]. The PIH were 100%, 87%, 57% and 33%, respectively. These results indicate that the essential oil of T.vulgaris could be considered as an alternative to control this parasite. [1] Gutiérrez, M.M., Werdin González, J., Stefanazzi, N., Serralunga, G., Yañez, L., Ferrero, A.A., 2012. Prevalence of Pediculus humanus capitis infestation among Kindergarten children in Bahia Blanca city, Argentine. Parasitol Res 111:1309-1313. [2] Werdin González, J.O., Gutiérrez, M.M., Murray, A.P., Ferrero, A.A., 2011. Composition and biological activity of essential oil from Labiatae against Nezara viridula (Hemiptera: Pentatomidae), soybean pest. Pest Manag Sci. 67: 948-955.   Financial support: SECyT- UNS.