 Seed treatments with the systemic fungicides metalaxyl and mefenoxam have been widely used to prevent systemic infections of Sorghum Downy Mildew.Metalaxyl, which inhibits protein synthesis in the pathogen, can also be applied as a foliar spray.In Texas, use of these two fungicides, in conjunction with the use of resistant hybrids, made the disease a minor problem until one of the pathotypes endemic in the region evolved resistance to both chemicals.