Although white rot caused by Botryosphaeria dothidea is one of the most important diseases of apple (Malus domestica) in Brazil during rainy summer seasons, local information on the disease and pathogen is scarce. The aim of this research was to define methods of inoculating B. dothidea on apple fruits without wounding them, to detect latent infection and to analyze the temporal and spatial patterns of the disease in a commercial orchard. The best results of inoculum production were obtained on PDA covered with filter paper. The higheest apple infection rates were obtained after two days in a humid chamber before inoculation with a conidial suspension carried by a piece of paper. Latent infection was better detected when infected fruits were disinfested with NaOCl, 1.25% of active chlorine and 9.6 ºGL of ethylic alcohol for 2 min. Production of B. dothidea on pruning stems occurred in different periods of each season. The disease distribution in a fungicide treated orchard showed clear aggregation of diseased plants but slight aggregation of fruits inside the plant.
apple plants; temperate fruit crops; Botryosphaeria dothidea
