Colonization of Bentgrass Turf by Curvularia lunata After Leaf Clipping and Heat Stress. J. J. Muchovej, Departamento de Fitopatologia, Universidade Federal de Viçosa, 36570 Viçosa, MG, Brazil. H. B. Couch, Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg 24061. Plant Dis. 71:873-875. Accepted for publication 1 April 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0873.

Creeping bentgrass turfs were grown, clipped, and maintained at 2 cm in 7-cm-diameter cups and grown until 30 or 120 days old. Turfs either did or did not receive high air temperature stress and were clipped 128, 64, 32, 16, 8, 2, 1, or 0 hr before inoculation with Curvularia lunata. Results showed that C. lunata could colonize heat-stressed and/or old clipped leaves but could not infect and colonize juvenile or mature leaves. The amount of turf foliage that was susceptible to thinning by C. lunata depended on the physiologic age of the leaf tissue. As stresses of high air temperatures are placed on leaf tissues, a greater percentage of the leaf blades are forced into advanced senescence, thereby increasing their susceptibility to infection and colonization.

Keyword(s): Agrostis palustris.