Development of formulations based on linalool and methyl cinnamate: Testing of stability and evaluation of mosquito repellent activity and mortality against Culex quinquefasciatus.

Synthetic pyrethroid-based mosquito repellents are effective but can cause irritation and allergic effects. This study reveals the process of developing vaporizer formulations containing the natural compounds, linalool and methyl cinnamate, at a 5% concentration. The stability of the prepared formulation was confirmed using the methods of the Collaborative International Pesticides Analytical Council. Repellent and mortality activity were evaluated against Culex quinquefasciatus using formulations of methyl cinnamate (MCN05) and linalool (LNL05) and compared with a commercial Transfluthrin vaporizer (CMS) and a negative (Blank05). Formulation MCN05 showed promising repellency, lasting till 60 minutes, repelling 45% of mosquitoes. LNL05 and CMS were effective initially, but the activity declined after 30 minutes, with CMS showing rapid knockdown and hence reduced repellency. Blank05 lasted with the lowest effectiveness (28%) for 45 minutes. Repellency results demonstrated that MCN05 has a more sustained activity than CMS and Blank05 (negative). In the mortality study, the highest (99%) mortality was observed with CMS, followed by MCN05 (48%); LNL05 and Blank05 showed the least mortality.