Water management as a tool for malaria mosquito control? The case of the Office du Niger, Mali

A field study was carried out in the rice irrigation scheme Office du Niger, Mali, to observe malaria mosquito larval development as related to differences in field irrigation practices, such as water level, irrigation application and irrigation frequency. The main aim was to find out to what extent field water management can be considered as a tool for vector control for this irrigation system. The results show that minor differences in water management do result in small differences in mosquito development, with respect to larval densities and species composition. The main malaria vector for the area, An. gambiae s.l., developed predominantly in the first six weeks after transplanting. Due to improper drainage after harvest An. gambiae s.l. breeding quickly re-established on fields where small water pools remained. Although further research is needed, suggestions for mosquito control in the Office du Niger would be a strict performance of the agricultural calendar in combination with a rotation of transplanting in large blocks.