A combination of indoor spraying and insecticide-treated bed nets has slashed cases of malaria throughout sub-Saharan Africa, but now researchers are reporting widespread resistance of mosquitoes to the chemicals used to kill them. Agricultural pesticides appear to be playing a role. I traveled to Burkina Faso to meet some of the scientists studying this issue and talk with farmers impacted by malaria on a daily basis. I also investigated how the economics of the chemical industry have contributed to this situation. My feature for Environmental Health Perspectives was published today. I took this photo of a farmer on his way to spray cotton fields at the Naon family farm outside of Bobo-Dioulasso.  Cotton is the most important cash crop in Burkina Faso, and by far the most pesticide intensive one. Most of the chemicals used on cotton farms are also used to control the mosquitoes that spread malaria.