The field experiments were conducted on the Purdue University Agronomy Farm in the summer of 1972. Corn plants of row width 76 cm, plant population 52,500 plants per hectare, were grown on May 18 on the Chalmers soil having a smooth surface and of silty clay loam texture.
The experimental design is shown in the map. The experiment was designed by Dr. M. Bauer and Dr. J. Cipra of the Laboratory for Applications of Remote Sensing, Purdue University.
Southern corn leaf blight (SCLB) is caused by the fungus Helminthosporium maydis. The disease has been known for many years and is wide spread in corn-growing tropical areas of the world. Symptoms of SCLB are the appearance of brown lesions on the lower leaves; The lesions grow in size and spread to upper leaves until the entire plant is prematurely killed. The corn fields were rated from blight level 0 (healthy corn) to blight level 5 (very severe blight) based on the amount of leaf damage.
Two hybrids Pioneer 3306 and Pioneer 3571 were chosen for growing corn. One of the objectives of the experiment was to determine if there was any statistically significant difference in the spectral response of the Pioneer 3306 corn and Pioneer 3571 corn. Texas male-sterile cytoplasm (TMS) and normal cytoplasm versions of Pioneer 3306 corn and Pioneer 3571 corn were grow. Helminthosporium maydis (H. maydis) causes relatively mild infection on corn of normal (N) cytoplasm, but it attacks corn of TMS cytoplasm with unusual virulence which causes southern corn leaf blight. The TMS corn plots 3, 5, 10, and 14 were inoculated with H. maydis on July 14.