Malaria is one of the leading causes of illness and death around the world. The disease is primarily caused by the bite of mosquitoes carrying a parasite. In 2019, around 229 million malaria cases were reported with an estimated number of 409,000 deaths. Most of the reported cases occurred in sub-Saharan Africa. Children younger than five years and pregnant women are most prone to malaria. To prevent malaria, the World Health Organisation (WHO) recommends spraying insecticides indoors and using bed nets treated with long-lasting insecticide. These interventions have one big flaw, however. They focus on minimising malaria infections indoors. Infections can still occur outdoors. And in some African countries resistance to insecticides – especially pyrethroids – is emerging. So new methods to control mosquitoes are needed urgently.