Bud vs skeeters! Evaluating the toxic and repellent effect of hemp extract against yellow fever mosquitoes

The yellow fever mosquito, Aedes aegypti is one of the most dangerous animals in the world, due to its ability to vector pathogens that can cause deathly debilitating diseases in humans and animals. The widespread use of pyrethroid insecticides to control this mosquito has resulted in resistance, which is why alternative insecticides with novel modes of action are needed to broaden our control methods. Secondary metabolites of plants are considered a promising source for discovering insecticides with novel modes of action for controlling mosquitoes. The hemp plant, Cannabis sativa, is known to produce many secondary metabolites, but there is little knowledge about their impact on the survival and behavior of Ae. aegypti. Here we characterize the toxic and repellent effect of hemp extracts against Ae. aegypti. We hypothesized that hemp extracts would kill and/or delay development of juvenile (larval) aquatic mosquitoes as well as repel adult female (blood feeding) mosquitos. Our results show that hemp extracts elicit larvicidal and repellent effects against Ae. aegypti. We conclude that hemp extracts may serve as a promising source of new compounds for developing insecticides and repellents to control mosquito vectors.