title: Persistence of Vectobac WDG and Metoprag S-2G against Aedes aegypti larvae using a semi-field bioassay in Rio de Janeiro, Brazil.
abstract: Persistence of Bacillus thuringiensis var. israelensis (Vectobac WDG) and methoprene (Metoprag S-2G) was evaluated against Aedes aegypti late third instar larvae of the Rockefeller strain in a semi-field bioassay. Tests were performed in Rio de Janeiro, using containers made of plastic, iron, concrete and asbestos, placed in a shaded area. The formulations used were 0.2 g of Vectobac-WDG and 1 g of Metoprag S-2G per 100 liters of water in house storage containers. Vectobac WDG was tested twice, in March and in April/May, 2002. In March (temperature ranging from 21.5 to 39.3 degrees C), 70-100% mortality was observed by the 7th day and declined abruptly thereafter. No significant differences were observed among the container types. In April/May (18.6 to 34.8 degrees C) mortality was higher than 70% to 30-36 days in all cases, except in the iron container (40% mortality on the 12th day). Metoprag S-2G was evaluated in April/May, 2002, and induced mortality higher than 70% up to 15 days in the plastic and iron containers and only seven days in the concrete container. In the asbestos container, maximal mortality was achieved on day one post-treatment (66%). Our results point to a low persistence of both formulations in the weather conditions of Rio de Janeiro.
authors.affiliation: Laboratório de Transmissores de Hematozoários, Departamento de Entomologia, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: José Bento Pereira
authors.initials: JB
authors.lastname: Lima
authors.forename: Nilson Vieira de
authors.initials: NV
authors.lastname: Melo
authors.forename: Denise
authors.initials: D
authors.lastname: Valle
mesh_terms: D000330:Aedes; D000818:Animals; D001413:Bacillus thuringiensis; D001681:Biological Assay; D001938:Brazil; D007814:Larva; D008726:Methoprene / Q000008:administration & dosage*; D010572:Pest Control, Biological / Q000379:methods*; D012621:Seasons; D013997:Time Factors
chemical_list: D008726:Methoprene