Epiphytic fluorescent isolates of the genus Pseudomonas (277), cultured from the fruit and leaf surfaces of citrus, were screened for antagonistic activity against green mould caused by Penicillium digitatum. Three of the Pseudomonas isolates showed greater activity than others against the pathogen in preliminary screening tests and were selected for subsequent experiments. Pseudomonas isolates were evaluated alone and in combination with 24 and 45°C sodium bicarbonate (3%) treatments on artificially inoculated Thomson navel oranges. The Pseudomonas isolates were completely tolerant to sodium bicarbonate up to a concentration of 3%. In addition, their efficacy for controlling green mould was improved when combined with the 3% sodium bicarbonate. A further increase in biocontrol activity was obtained when the bacterial isolates were applied in combination with hot sodium bicarbonate. It was concluded that using the fluorescent Pseudomonas spp. isolates in combination with a treatment of hot sodium bicarbonate could provide a practical alternative or complement to fungicides for postharvest control of green mould on oranges.