فرمولاسیون پودر بر پایه جدایه بومی باکتری بیمارگر Bacillus thuringiensis sub.sp. israelensis برای کنترل پشه‌ها (Diptera: Culicidae)

Mosquitos (Diptera: Culicidae) are among the most important insect pests affecting the health of people and animals by direct feeding on blood or/and transmitting a variety of diseases such as malaria, dengue fever and yellow fever. A variety of management practices are recommended to protect homes from biting mosquitos. In some circumstances, however, areawide approaches are required to suppress mosquito population for example, when an insect-borne disease occurs or when population explosion threatens public health in a wide area. The use of the entomopathogenic bacterium, Bacillus thuringiensis sub.sp. israelensis (Bti), is among the most effective and environmentally-safe methods for areawide control of mosquito populations. In this study, the insecticidal activity of a new powdery formulation of an Iranian-native isolate of Bti (MH-14) was assayed against the fourth instar larvae of Culex pipiens. After cultivation on liquid broth culture in automatically controlled bioreactors with a working capacity of 8000 liter, the bacterial suspension was spray dried to a uniform creamy powder with a final concentration of >109 CFU/g viable spores. Laboratory bioassays were performed under semi-field condition to determine larval mortality 24 hours post treatment. According to the results, the median lethal dose of the powdery formulation (LD50) was estimated as 100 µg/L water. Results of this study highlight high insecticidal activity of Bt powdery formulation against mosquito larvae. Given the local facilities for mass production and formulation of the biological control agent, Bti can be considered as an ideal option for management of mosquito populations, especially during outbreaks or insect-borne disease epidemics.