title: Ammonium sulphate fertiliser increases larval populations of Anopheles arabiensis and culicine mosquitoes in rice fields.
abstract: Field experiments were conducted in central Kenya, to study the effect of ammonium sulphate fertiliser ((NH(4))(2)SO(4)) on mosquito larval populations in rice fields. The experiments used a complete randomised block design having four blocks with two experimental ponds per block, and the fertiliser and control treatments allocated randomly among the ponds. Student's two-sample unpaired t-test was used to test for the significance of differences between the relative counts of larvae in fertiliser and control treatments. The results showed a significant overall increase in the larval populations of An. arabiensis (P<0.01) and culicine mosquitoes (P<0.05), after ponds were treated with the fertiliser. Significantly more fourth instar larvae of An. arabiensis were collected in fertiliser than control plots (P<0.001). An. arabiensis data indicated that the first fertiliser application had the most impact, compared to the second and third applications. This was evident in a significant peak of combined first and second instar An. arabiensis larvae observed 5 days after the first fertiliser application (P<0.05). The studies suggest that ammonium sulphate fertiliser reduces turbidity of water in rice fields, thereby making them visually more attractive for egg-laying by An. arabiensis and culicine mosquitoes.
authors.affiliation: International Water Management Institute (IWMI), Private Bag X813, 0127, Silverton, Pretoria, South Africa. c.mutero@cgiar.org
authors.forename: C M
authors.initials: CM
authors.lastname: Mutero
authors.forename: P N
authors.initials: PN
authors.lastname: Ng'ang'a
authors.forename: P
authors.initials: P
authors.lastname: Wekoyela
authors.forename: J
authors.initials: J
authors.lastname: Githure
authors.forename: F
authors.initials: F
authors.lastname: Konradsen
mesh_terms: D000645:Ammonium Sulfate / Q000494:pharmacology*; D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000469:parasitology / Q000502:physiology; D018556:Crops, Agricultural; D005308:Fertilizers; D007814:Larva / Q000187:drug effects / Q000469:parasitology / Q000502:physiology; D012275:Oryza; D011156:Population Density; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D005308:Fertilizers; D000645:Ammonium Sulfate