This research was conducted to evaluate some epidemiological features of the rose apple (Syzygium jambos) rust (Puccinia psidii Winter) under field conditions at the Universidade de Brasília, Brasília, DF, Brazil, from March 29 through December 31, 1988. Data for the amount of airborne urediniospores were collected in ten plants, using a Burkard's seven-day volumetric spore trap set between two rose apple trees. Most of the airborne urediniospores were collected between June 23 and July 6, from 10 a.m. to 1 p.m. The major quantity of S. jambos affected shoots occurred between April 28 and July 20. There was a positive correlation between the amount of trapped urediniospores and infected young shoots. A negative correlation was shown between temperature (12h) and number of airborne urediniospores. The number of days with relative humidity (RH) > or = 80% was positively correlated to the amount of deformed shoots. Also, the amount of urediniospores and infected young shoots were positively correlated to the number of days with night (24h) temperature <=20ºC or night RH > or = 80%. These data show that this disease was favored by low temperatures (<=20ºC), high night RH ( > or = 80%) and high levels of airborne urediniospores.
Puccinia psidii; Syzygium jambos; plant diseases; environmental factors
