Why does PermaNet® 3.0 have an increased efficacy with pyrethroid-resistant malaria vectors?

The synergist increases the efficacy of the deltamethrin and works in two major ways: by enhancing the penetration of the deltamethrin into the insect¹ and by inhibiting the metabolic enzymes the mosquito uses to sequester or break down this insecticide².

References

1. Ahmad, M. et al (2006) Delayed cuticular penetration and enhanced metabolism of deltamethrin in pyrethroid-resistant strains of Helicoverpa armigera from China and Pakistan.  Pest Manag. Sci.  62: 805 – 810.
2. Moores, G. et al. (2005). Use of 'temporal synergism' to overcome insecticide resistance. Outlooks on Pest Management 16(1): 7-9.