Large Scale Field Inoculation and Scoring of Maize Southern Leaf Blight and Other Maize Foliar Fungal Diseases

Field-grown maize is inoculated with Cochliobolus heterostrophus, causal agent of southern leaf blight disease, by dropping sorghum grains infested with the fungus into the whorl of each maize plant at an early stage of growth. The initial lesions produce secondary inoculum that is dispersed by wind and rain, causing multiple cycles of infection that assures a high uniform disease pressure over the entire field by the time of disease scoring, which occurs after anthesis. This method, with slight modifications, can also be used to study the maize fungal diseases northern leaf blight (caused by Exserohilum turcicum) and gray leaf spot (Cercospora zeae-maydis).