Effect of Leaf Wetness, Fertilizer Rate, Leaf Age, and Light Intensity Before Inoculation on Bacterial Leaf Spot of Chrysanthemum. J. B. Jones, Assistant Professor of Plant Pathology, University of Florida, IFAS, Gulf Coast Research and Education Center, 5007 60th Street East, Bradenton 34203. A. R. Chase, Associate Professor of Plant Pathology, University of Florida, IFAS, Agriculture Research and Education Center, Route 3, Box 580, Apopka 32703; B. K. Harbaugh, University of Florida, IFAS, Gulf Coast Research and Education Center, 5007 60th Street East, Bradenton 34203; and B. C. Raju, Chief Plant Pathologist, Yoder Brothers of Florida, Inc., P.O. Box 68, Alva 33920. Plant Dis. 69:782-784. Accepted for publication 2 February 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-782.

Potted Iceberg chrysanthemum plants were grown at four controlled-release fertilizer rates and two light intensities. As fertilizer rate increased, the number of lesions caused by Pseudomonas cichorii increased. Levels of nitrogen and phosphorus were positively correlated with disease severity. Lesion diameter and lesion incidence were greater on detached leaves from plants grown under high light conditions. Excised leaves from the bottom one-third of the plant were less susceptible than leaves from the middle or top of the plant. The number of lesions that developed on plants misted before inoculation increased with the duration of the mist period.