Enhancement of the efficacy of a combination of Mesocyclops aspericornis and Bacillus thuringiensis var. israelensis by community-based products in controlling Aedes aegypti larvae in Thailand

Abstract

Prolonged efficacy of a combination of bacteria (Bacillus thuringiensis var. israelensis [Bti] and copepods (Mesocyclops aspericornis) in controlling immature forms of Aedes aegypti in peridomestic water containers was achieved by adding various products from local villages as supplementary food for copepods. In all experiments, 100 first-instar larvae were added into the breeding containers every day for eight weeks. Combinations of biological control agents and each local supplementary food were applied once at the beginning of the experiment. At the end of the experiment, the average number of mosquito larvae in containers with a combination of copepods and Bti with one gram of rice grain had decreased to only 0.5% of that with no control agent. In comparison, the average numbers of mosquito larvae in containers with Bti only, or copepods only, were approximately 10% and 33% of those in containers with no control agents, respectively. In addition, the number of copepods in containers with mosquito larvae and supplementary food was at least three times higher than those with mosquito larvae alone.