The rotational use of
insecticides with different modes of action for indoor residual spraying (IRS) is recommended for improving
malaria vector control and managing insecticide resistance.
Insecticides with new chemistries are urgently needed.
Broflanilide is a newly discovered
insecticide under consideration. We investigated the efficacy of a wettable
powder (WP) formulation of
broflanilide (VECTRON T500) for IRS on mud and cement wall substrates in laboratory and experimental hut studies against
pyrethroid-resistant
malaria vectors in Benin, in comparison with
pirimiphos-methyl CS (
Actellic 300CS). There was no evidence of cross-resistance to
pyrethroids and
broflanilide in CDC bottle bioassays. In laboratory cone bioassays,
broflanilide WP-treated substrates killed > 80% of susceptible and
pyrethroid-resistant An. gambiae sl for 6-14 months. At application rates of 100 mg/m2 and 150 mg/m2, mortality of wild
pyrethroid-resistant An. gambiae sl entering experimental huts in Covè, Benin treated with VECTRON T500 was similar to
pirimiphos-methyl CS (57-66% vs. 56%, P > 0.05). Throughout the 6-month hut trial, monthly wall cone bioassay mortality on VECTRON T500 treated hut walls remained > 80%. IRS with
broflanilide shows potential to significantly improve the control of
malaria transmitted by
pyrethroid-resistant mosquito vectors and could thus be a crucial addition to the current portfolio of IRS
insecticides.