Larvicidal and Pupicidal Activity of Neem Oil (Azadirachta indica) Formulation against Mosquitoes Aedes albopictus (Skuse, 1894) (Diptera: Culicidae)

The control against mosquitoes should be specifically directed at the larvae. Combating the adults is temporary, ineffective and polluting the environment, while larval treatment is more localised in time and space and is thus less dangerous. The aim of our work is to evaluate the insecticidal activity under laboratory conditions of a new natural anti-mosquito formulation (neem oil, a.i azadirachtin A 0.3%) against A edes albopictus. The neem oil (azadirachtin A 0.3%) was tested in water at different dosages: 5 mg; 10 mg; 25 mg; 50 mg and 75 mg on larvae at the stages L1-L2, L3-L4 and pupae. Four replicas were conducted. The LD50 and LD90 levels were 14 mg (95%; CI = 5-19 mg) and 70 mg (95%; CI = 27.9-98.1 mg), respectively, for the larvae at the stages L1-L2 and 20 mg (95%; CI = 4.4-24.4 mg) and 30 mg (95%; CI = 3.6-50.4 mg), respectively, for the larvae at the stages L3-L4. Regarding the treatment at the pupal stage, after the first 24h, there is a higher mortality rate compared to the control, showing its effectiveness as pupicide.