Authors familiar with green and blue moulds of citrus had mistaken the fungus for P. italicum and dismissed its unique features as variations due to particular environmental conditions. To date, P. ulaiense has been reported in Argentina, Arizona, Australia, California, Florida, Italy, New Zealand, South Africa, Taiwan, and Texas. In recent times, P. ulaiense has been reported in Egypt as a postharvest pathogen of orange fruit.
Experts well-versed in green and blue moulds of citrus incorrectly identified the fungus as P. italicum, attributing its distinct characteristics to environmental factors rather than recognizing it as a unique species. To this day, P. ulaiense has been documented in various parts of the world, including Argentina, Arizona, Australia, California, Florida, Italy, New Zealand, South Africa, Taiwan, and Texas. Lately, P. ulaiense has been recognized in Egypt as a postharvest pathogen affecting orange fruit.