Toxicity of different nitrogenous fertilizers on Aedes aegypti larvae (Linnaeus) (Diptera: Culicidae)

The dengue mosquito, Aedes aegypti (L.) (Diptera: Culicidae) is a vector of various harmful viral diseases like dengue fever, yellow fever, zika, and chikungunya virus. This pest is mainly controlled using residual insecticides including chorpyrifos-ethyl, temephos, deltamethrin, lambda-cyhalothrin, permethrin which pose a serious threat to public health and the environment. The use of nitrogenous fertilizers in crop production may have toxicity to non-target species such as Ae. aegypti. Therefore, the present study explores the toxicity of five fertilizers, i.e. urea, nitrophos (NP), ammonium sulphate (AS), single super phosphate (SSP) and diammonium phosphate (DAP) against the larvae of Ae. aegypti collected from Multan and Faisalabad. For this purpose, larvae were exposed to 4-5 doses of each fertilizer using the tank application method. The results indicated that all five fertilizers caused larval mortality. Single super phosphate fertilizer caused higher mortality with lower LC50 values (1.5-3.5 g/L) compared to other fertilizers. LC50 values of Multan population of Ae. aegypti were less than the Faisalabad population. The findings reveal that the tested fertilizers probably have toxic effects on the larvae of Ae. aegypti under laboratory conditions, and may also have important implications for the management of dengue mosquitoes in Pakistan.