Horn flies (Haematobia irritans), pictured above, and the stable flies (Stomoxys calcitrans) are serious pests of the North American cattle industry, causing annual economic losses exceeding $1 billion. In the open-access Journal of Integrated Pest Management, a new in-depth review of existing research highlights the promising repellent and insecticidal qualities of more than 20 different botanical compounds, such as neem oil, pyrethrum, and even nepetalactone, the essential oil of catnip. (Public domain image: Wikimedia)