Browsing by Autor "Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca"

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    Repellent activity of the essential oil from Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae) on Triatoma infestans (Klug) (Reduviidae)
    (University of Santiago, 2020) Marycruz Mojica; Raúl A. Alzogaray; Sofía L. Mengoni; Mercedes María Noel Reynoso; Carlos F. Pinto; Hermann M. Niemeyer; Javier Echeverría; Centro de Investigaciones de Plagas e Insecticida; Carlos Pinto; Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca
    Triatoma infestans (Klug) is the principal vector of Chagas disease in Bolivia and neighboring countries. The objective of this study was to determine the chemical composition of the EO of the Chilean laurel, Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae) and to evaluate its repellent effect on fifth-instar nymphs of T. infestans. The EO from L. sempervirens was obtained by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Their main components were cis-isosafrole (89.8%), terpinene (3.9%), trans-ocimene (2.7%) and methyleugenol (2.2%). Repellency was evaluated on a circle of filter paper divided into two equal zones which were impregnated with test substances [EO or N,N-diethyl-3-methylbenzamide (DEET) as positive control] and acetone as blank control, respectively. Several concentrations of test substances between 4.125 and 132 g/cm 2 were tested. The EO from L. sempervirens produced significant repellency at concentrations equal or above 66.0 g/cm 2 , while DEET repelled starting at 16.5 g/cm 2 . Future works will be oriented to the study of repellent properties of cis-isosafrole alone and mixed with -terpinene, trans-ocimene and methyleugenol on T. infestans.
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    Smoke of Capsicum baccatumL. var. baccatum (Solanaceae) repels nymphs of Triatoma infestans(Klug) (Hemiptera: Reduviidae)
    (University of Santiago, 2021) Jhean-Carla Echalar; Romina Cossio‐Rodríguez; David Véliz; Fabricio Cardozo-Alarcón; Hermann M. Niemeyer; Carlos F. Pinto; Fabricio Cardozo-Alarcon; Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca; Hermann M. Niemeyer; Universidad de Chile
    Control of the Chagas disease vector, Triatoma infestans(Klug) (Hemiptera: Reduviidae) with synthetic pesticides in Bolivia has become increasingly inefficient due to the development of resistance in the insects. In the Chaco region of Bolivia, guaraní populations have approached the problem by fumigating their houses with the smoke of native plants. Through interviews and field work with local guides, the main plant used by the guaraníes was collected and later identified as Capsicum baccatumL. var. baccatum(Solanaceae). In choice bioassays, filter papers exposed to the smoke of the plant repelled nymphs of T. infestans. Activity remained significant after storing the exposed filter papers for 9 days. Chemical analysis of smoke and literature data suggested that capsaicinoids present in the smoke were responsible for the repellent effect. The data presented provide a rationale for the use of C. baccatumvar. baccatumto control the Chagas vector bythe guaraní populations.