Effect of Alternaria Leaf Blight on Soluble Solids Content of Muskmelon. RICHARD LATIN, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907. KAREN K. RANE, and KATHERINE J. EVANS, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907. Plant Dis. 78:979-982. Accepted for publication 18 July 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0979.

Soluble solids content (SSC), a measure of fruit quality, was determined from muskmelons sampled periodically from experimental field plots that sustained Alternaria leaf blight epidemics of varying intensity. The relationship between epidemic severity and two quantitative representations of the change in SSC during the sampling period (SSCAREA and SSCINDEX) was investigated. Epidemic severity was represented by the area under the disease progress curve and apparent infection rate. Results show that SSC decreased with increased severity of Alternaria leaf blight epidemics. Interpretation of these results justifies periodic application of protective fungicides to reduce losses caused by the disease.