Chemical fertilizers are used everywhere, which often pollute the breeding sites of mosquitoes. In this laboratory study, the consequences on Aedes aegypti (L.) (Diptera: Culicidae) and Anopheles gambiae (Giles) (Diptera: Culicidae) of water-containing plant matter (PM) alone, or in association with an NPK type of fertilizer (PM+NPK), were evaluated. To obtain a 20% imaginal emergence of An. gambiae (IEt₂₀), the bioassays carried out with PM have evidenced that its larvae need four times as much food as for Ae. aegypti larvae. The PM+NPK combinations significantly improve the survival rates of both mosquitoes multiplying the percentages of imaginal emergence by 1.7–3 (synergistic effect). The log-probit analysis of the adult emergence also reveals that the environments containing fertilizers accelerates by two to four times the development of the mosquito larvae.