关键词: 苏云金杆菌, 媒介蚊虫, 生物防治, 淡色库蚊

Abstract: Objective　To study the activity and efficacy of Bacillus thuringiensis serotype H-14 (B.t. H-14) against vector mosquitoes and the persistence of bacterial liquid preparation. Methods　B.t. H-14 with high pathogenicity against mosquitoes was tested in the field sites. The densities of larval and adult mosquitoes were quantified by dippingand human-baited net trapping. The results were compared with the mosquito densities in an untreated control site to determine the field efficacy of B.t. H-14. The persistence of B. thuringiensis in different water bodies was observed in the laboratory. Results　The relative population index (RPI) of vector mosquitoes was under 10 during peak periods, which indicated that B.t. H-14 lowered the populations of vector mosquitoes in natural habitats. The mosquito densities in the treated site remained at a relatively low level, with a larval density less than 50/dip and an adult density less than 20/hour. However, the density of mosquitoes in the untreated control site changed considerably with seasons, with a larval density more than 100/dip and an adult density up to 188/hour. In the laboratory, the activity of B.t. H-14 lasted 30 d. The larvicidal activity of B.t. H-14 was optimal in pure water; in polluted water, however, its activity reached the peakin one weekand then decreased gradually. Conclusion　In the natural environment, B.t. H-14 can be used to control vector mosquitoes, and the concentration of bacterial liquid applied and the number of applications can be determined according to the mosquito population densities.

Key words: Bacillus thuringiensis, Vector mosquito, Biological control, Culex pipiens pallens