Abundance and control of malaria mosquito larvae in the traditional water management agro-ecosystem of Kasagam, western Kenya

Abstract

This study investigated the abundance and control of malaria mosquito larvae in a traditional water management agro-ecosystem of Kasagam, Kisumu City, western Kenya. The study of larval habitats of malaria vectors is important in determining abundance and fitness of resultant adult mosquito populations and planning for suitable control measures. Dominant types of plants found in the study site were identified, recorded and categorized. Sampling of mosquito larvae was done in particular habitats with different plant cover types, water management practices, growth phases of rice and larval control methods. Anopheles gambiae Giles sensu stricto larvae were fed on different diet based treatments while others were subjected to different larval control treatments. Out of 2494 L3-lA Anopheles mosquito larvae identified in Kasagam, 3.93% were An. arabiensis Patton, 0.76% were An. funestus Giles while 95.31% were nonvector species of malaria. Abundance of larval stages of anopheline mosquito larvae was significantly influenced by plant cover types (P < 0.001), rice growth phases (P < 0.001) and larval control methods (P < 0.001). However, the density of anopheline mosquito larvae was not significantly influenced by the tyE..~so~f water management practices (P = »-.;.,.. 0.174) as compared to culicine (P < 0.003). Contrastingly, different plant cover types (P = 0.462), rice growth phases (P = 0.104) and larval control methods (P = 0.960) showed no significant difference in the habitat abundance of different types of late instar (L3 and L 4) stages of anopheline-mosquitoes identified. Diet based treatments were observed to have a significant effect on larval survival (P < 0.001), development period (P < o.OOr) and body size (P < 0.001) of An. gambiae s.s mosquitoes. Traditional water management agro-.ec,o-system practices and larval control methods influence the abundance of malaria mosquito larvae in Kasagarn, Kisumu city.