Cultural practices. Given the strong relationship between infested surface residue and the development of gray leaf spot, management strategies aimed at reducing the amount of residue are among the most effective in preventing severe epidemics of this disease. Cefcospom zeae-mayd/s is known to be pathogenic only to maize and according to Latterell and Rossi (34), does not survive in maize residue in the field beyond one year. One-to-two years of rotation away from maize is dften enough to reduce the survival of the fungus (39). However, the effectiveness of crop rotation and tillage depends on their widespread adoption, since neighboring fields may serve as sources of inoculum. Other cultural practices that may be effective against gray leaf spot are planting date and genotype maturity. Both of these approaches aim at avoiding disease-favorable conditions and delaying the onset of the disease. Late-maturing hybrids are at greater risk from gray leaf spot than early maturing hybrids because they are exposed to the disease during a greater portion of the grainfill period (54).