Community-based management of the malaria vector Anopheles gambiae larvae with Neem (Azadirachta indica) leaves in economically-challenged villages in West Africa

Malaria is a vector-borne disease affecting millions of people across the globe. Unfortunately, malaria management can be difficult for individuals and communities in areas with high rates of transmission due to poverty and lack of education about malaria. The neem tree shows insecticidal and medicinal properties attributed to azadirachtin and closely related active compounds. We tested the hypothesis that neem tree (Azadirachta indica) leaves could be used successfully as part of sustainable, community-based IPM for mosquito larvae in Mali (West Africa). Neem leaf slurries are made by crushing neem leaves in water with a mortar and pestle, a tool commonly used by village women for preparing food. In laboratory bioassays, we used leaf samples from Mali and a mortar and pestle to create slurries similar to those produced in villages. Mortality of third and fourth instar larvae were separately assessed at timed intervals after larvae were placed into treated water. Laboratory results showed that the easy-to-produce, technologically-simple neem leaf slurry can be used as a larvicide for mosquitoes. Field results with Bti as a model demonstrated the ability of Malian villagers to manage mosquito larval populations once biological cycles were understood. Neem leaf slurries have the potential to be a no-cost alternative to commercial larvicides. In combination with improved knowledge of the mosquito and malaria protozoan lifecycles, village residents living in poverty will be able to effectively use neem leaves to manage mosquito populations and control malaria.