EPIDEMIOLOGY OF POWDERY MILDEW ON MANGO BLOSSOMS

Conidia of Oidium mangiferae, the causal organism of powdery mildew on mango, were trapped in a mango orchard during the periods of flowerin g 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. T he number of trapped airborne conidia of O. mangiferae was characteriz ed by a distinct diurnal periodicity. The greatest number of conidia w ere trapped between 1100 and 1600 hours. The first disease symptoms of powdery mildew occurred at approximately the same time each year. Inf lorescences were susceptible beginning when the main axes changed colo r and ending at fruit set.