Honduras : field evaluations of Bacillus thuringiensis var. israelensis (Bti) against Anopheles larvae

israelensis serotype H-14, or Bti, have provided a highly selective and safe biological control agent that will rapidly kill mosquito larvae while leaving mosquito predators and other non-target organisms unharmed. This report summarizes the findings of field trials conducted in Honduras to examine the acute effect of Bti application on Anopheles larvae and other mosquito populations, the first such evaluation performed in Latin America. The field tests definitively showed that Bti was very effective in reducing Anopheles larvae to low levels. The tests were done in a sufficient variety of habitats (ricefields, lagoons, a canal, and a flooded pasture), indicating that Bti can have broad application to the diverse habitats in which Anopheles larvae are found in Honduras. It also demonstrated that granular and liquid formulations of Bti worked equally well at high rates of application, and that the two malaria vector species that occur in the test sites, An. albimanus and An. pseudopunctipennis, were both affected by the Bti treatment. The report concludes that although testers used high rates of application, both granular and liquid rates could possibly be reduced by 50-75% and still produce an acceptable percentage reduction of larvae.