VIEW ARTICLE

Spectral Reflectance and Transmittance of Corn Leaves Infected with Helminthosporium maydis. G. R. Safir, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48823; G. H. Svits(2), and A. H. Ellingboe(3). (2)Infrared and Optics Laboratory, Willow Run Laboratory, University of Michigan, Ann Arbor 48104; (3)Department of Botany and Plant Pathology, Michigan State University, East Lansing 48823 Phytopathology 62:1210-1213. Accepted for publication 1 May 1972. DOI: 10.1094/Phyto-62-1210.

Corn leaves with Texas male sterile cytoplasm have greater reflectance and transmittance after inoculation with Helminthosporium maydis than do healthy leaves. The differences were the most pronounced in the chlorophyll (0.5-0.7 µ) and water (1.45 and 1.95 µ) absorption regions of the spectrum. The first measurable, reproducible increase in reflectance of diseased over healthy tissue was detected when disease lesions became visible to the eye, about 40 hr after inoculation. The earliest changes were confined to the chlorophyll absorption regions of the spectrum. On normal cytoplasm corn, the increases in reflectance and transmittance of diseased over healthy tissue are smaller in magnitude and show up later than on T cytoplasm corn.