The disease may cycle and reproduce infection spores every two to three weeks. Gray Leaf Spot will not develop if one of the three ingredients of the disease triangle is not present. Disease inoculum is directly related to the amount of infected corn residue remaining on the soil surface. Pathologists attribute the recent increase of GLS pressure to the expansion of acres farmed with no-till and conservation tillage practices in the last five years. Disease development is favored by temperatures of 70 to 86 degrees F and high moisture conditions.
Resistance does vary among hybrids, however no hybrid is immune to the disease.
Delaying Disease Development is Key To Successful Management Proper residue management can reduce the amount of GLS inoculum available to infect the growing crop. Reducing the amount of inoculum retards the rate of disease development. Residues can be managed through tillage, burning, and or crop rotation. Crop residue is the main source of GLS inoculum. GLS development may also be slowed by the use of hybrids with increased resistance.