Mosquito Densovirus (MDV) belongs to the genus Densovirus of parvovirinae. It is a single positive-stranded DNA virus with an uncoated viral capsid and a regular icosahedral structure with a diameter of 20 nm. After mosquitoes are infected with MDV, their activities are greatly reduced and distorted, and spasmodic convulsions occurred after stimulation, and some die. The time of pupation and emergence of the surviving larvae is delayed, and they are prone to die when molting. After the virus infection, the life span of adult mosquitoes will be shortened, thereby reducing the chance of mosquitoes transmitting pathogens, and the oviposition rate and oviposition vitality of female mosquitoes after infection will also be greatly reduced. The virus can spread not only horizontally through larvae and adults, but also vertically by female mosquitoes, so that the virus can spread to various breeding water bodies and continue in nature.
Bacillus thuringiensis subsp. Israel, namely Bti, is a pathogenic bacterium with specific effects on mosquito larvae. The main active substance of Bti is the toxin in crystallin. When crystalline and spores are swallowed by the larvae, they enter the midgut through oral cavity and release toxicity, which causes septicemia and general paralysis, so that larvae stop feeding and finally dying of starvation.
