Epidemiology of Powdery Mildew on Mango Blossoms. M. H. SCHOEMAN, Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200 South Africa. B. Q. MANICOM, Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200 South Africa; and M. J. WINGFIELD, University of the Orange Free State, Department of Microbiology, P.O. Box 339, Bloemfontein 9300 South Africa. Plant Dis 79:524-528. Accepted for publication 2 November 1994. Copyright 1995 The American Phytopathological Society 524. DOI: 10.1094/PD-79-0524.

Conidia of Oidium mangiferae, the causal organism of powdery mildew on mango, were trapped in a mango orchard during the periods of flowering and fruit set from 1989 1991. Hourly aerial conidial concentrations were correlated positively with hourly temperature and negatively with hourly relative humidity, vapor pressure deficit, and leaf wetness. The number of trapped airborne conidia of O. mangiferae was characterized by a distinct diurnal periodicity. The greatest number of conidia were trapped between 1100 and 1600 hours. The first disease symptoms of powdery mildew occurred at approximately the same time each year. Inflorescences were susceptible beginning when the main axes changed color and ending at fruit set.