Synergistic Behavioral Response Effect of Mixtures of Andrographis paniculata, Cananga odorata, and Vetiveria zizanioides against Aedes aegypti (Diptera: Culicidae)

SIMPLE SUMMARY: In several Asian and Latin American nations, severe dengue is the main cause of serious disease and death. Dengue viruses are transmitted to humans via the bite of an infected Aedes species. Personal protection measures may be an effective method of avoiding mosquito bites. Nowadays, consumers are increasingly interested in commercial repellent products containing plant-based ingredients because they are perceived as “safe” in comparison to long-established synthetic repellents. We tested a binary plant-based mixture formulation of Cananga odorata, Vetiveria zizanioides, and the crude extract of Andrographis paniculata on laboratory and field strains of Aedes aegypti using an excito-repellency test system. The results showed that a mixture of V. zizanioides and A. paniculata at a 1:4 ratio was better than DEET. These results could lead to the further development of a combination of V. zizanioides and A. paniculata as active ingredients in a repellent that could be tested in human trials. ABSTRACT: Each binary mixture formulation of Vetiveria zizanioides (L.) Nash (VZ) with Andrographis paniculata (Burm.f.) Wall. ex Nees (AP) or Cananga odorata (Lam.) Hook.f. & Thomson (CO) and AP with CO at 1:1, 1:2, 1:3, and 1:4 ratios (v:v) was investigated for behavioral responses on laboratory and field strains of Aedes aegypti. Irritant and repellent activities of each formulation were compared with N,N-diethyl-3-methylbenzamide (DEET) using an excito-repellency test system. The result demonstrated that the mixture of VZ:AP in all combination ratios was the most effective in inducing an irritancy response against the laboratory strain (56.57–73.33%). The highest percentage of escaped mosquitoes exposed to the mixture at a 1:4 ratio (73.33%) was significantly different from DEET (26.67%) (p < 0.05). Against the field strain, the strongest escape response of AP:CO at a 1:1 ratio in the contact trial (70.18%) was significantly different compared with DEET (38.33%) (p < 0.05). There was a weak non-contact escape pattern in all combinations of VZ:CO against the laboratory strains (6.67–31.67%). These findings could lead to the further development of VZ and AP as active ingredients in a repellent that could advance to human use trials.