Abstract
The use of Bacillus thuringiensis (Bt) to control insect pests has already been established in
various agronomic and forest crops. It is a bacterium that does not pollute the environment,
is safe for mammals and vertebrates, lacks toxicity to plants and specifically targets insects.
To date in-depth studies have not been conducted about the use of Bt to control the main
pest of mahogany (Swietenia macrophylla King) and other Meliaceae species, the Hypsipyla
grandella Zeller (Lepidoptera: Pyralidae). Therefore, this study aimed to test the pathogenicity
of Bt strains on H. grandella caterpillars, as well to determine the lethal concentration
required to kill 50% of the population (LC50) of the most promising strains. Ten strains
of Bt toxic to lepidopteran proven in previous trials were used and these were incorporated
into a natural diet with mahogany seeds to check their mortality. The LC50 of the top
five strains was determined. The results indicate that H. grandella is highly susceptible to
Bt toxins and the S1905 strain is highly toxic. Therefore, the use of Bt strains may be a tool
to be incorporated into the integrated management of this important pest.
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Authors and Affiliations
de Castro Marcelo Tavares
Montalvăo Sandro Coelho Linhares