Female Anopheles mosquitoes lay their eggs on the surface of still or slow-moving water. The eggs hatch into aquatic larvae, which live just under the surface, breathing air through openings called spiracles, and feed on microorganisms. The larvae develop into pupae and then adults in about one to two weeks. Attacking these aquatic stages (larval source management) reduces the number of adult mosquitoes, and so reduces malaria transmission.
Removing breeding sites
• draining swamps, ditches and puddles, and filling in holes
• covering water tanks and emptying containers such as old tyres and pots
• improving drainage around homes.Chemical control
• spreading a thin film of oil on the water surface, which stops larvae and pupae getting air, so they die by suffocation
• adding larvicides, chemicals that kill larvae.Biological control
• stocking ponds with fish that eat mosquito larvae, such as Gambusia (mosquitofish)
• adding the bacterium Bacillus thuringiensis israelensis (Bti), whose toxin kills mosquito larvae but is harmless to most other organisms
• releasing sterile males, which mate with females so that no offspring are produced.These methods work best where breeding sites are few, fixed and easy to find. In rural Africa, Anopheles breed in countless small puddles and hoof prints after rain, so larval control is usually combined with bed nets and spraying. Oil and some larvicides can also harm other aquatic organisms.
Removing breeding sites• draining swamps, ditches and puddles, and filling in holes
• covering water tanks and emptying containers such as old tyres and pots
• improving drainage around homes.Chemical control
• spreading a thin film of oil on the water surface, which stops larvae and pupae getting air, so they die by suffocation
• adding larvicides, chemicals that kill larvae.Biological control
• stocking ponds with fish that eat mosquito larvae, such as Gambusia (mosquitofish)
• adding the bacterium Bacillus thuringiensis israelensis (Bti), whose toxin kills mosquito larvae but is harmless to most other organisms
• releasing sterile males, which mate with females so that no offspring are produced.These methods work best where breeding sites are few, fixed and easy to find. In rural Africa, Anopheles breed in countless small puddles and hoof prints after rain, so larval control is usually combined with bed nets and spraying. Oil and some larvicides can also harm other aquatic organisms.