Persistence of Vectobac WDG and Metoprag S-2G against Aedes aegypti larvae using a semi-field bioassay in Rio de Janeiro, Brazil.
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.
Lima
José Bento Pereira
JB
Laboratório de Transmissores de Hematozoários, Departamento de Entomologia, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
Melo
Nilson Vieira de
NV
Valle
Denise
D
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
D008726:Methoprene