Infection Cycle Components and Disease Progress of Gray Leaf Spot on Field Corn

Abstract

The epidemiology of gray leaf spot disease (GLS) on field corn (Zea mays) was studied following artificial inoculation with the fungus, Cercaspara zeae-maydis. Studies were based on relative differences in selected infection cycle components between a susceptible and a moderately resistant corn hybrid. Area under the disease progress curve, apparent infection rate, number of lesions, and sporulation capacity were lower and latent period was longer on the moderately resistant hybrid than on the susceptible hybrid. Based on comparisons of disease progress curves, infection cycle components, and rainfall patterns, it is postulated that rainfall and sporulation during early infection cycles have a significant effect on development of GLS. Management strategies aimed at decreasing levels of inoculum during early infection cycles are suggested as an effective means of reducing the severity of GLS