Pathogenic microbes employ specialized mechanisms to breach defense of host plants, causing diseases on plants and losses in agricultural production. Understanding mechanisms of pathogenesis offers new avenues for disease control. A team from Sichuan Agriculture University led by Xuewei Chen investigated mechanisms underlying the genera- tion of an infection structure called penetration peg, which is employed by many fungal pathogens such as the one causing blast disease on rice. They discovered that very-long-chain fatty acids are required for this process. They further demonstrated that a group of commercialized herbicides capable of inhibiting very-long-chain fatty acid biosynthesis in fungi can effectively inhibit pathogenesis of a broad spectrum of fungi, which brings new technology to control diseases and provides new ideas for new pesticides discovery.