How to recognize and combat purple rust in blackberries

The pathogen Phragmidium violaceum is a fungus that causes the disease known as violet rust in blackberries. This fungus belongs to the Phragmidiaceae family and is characterized by its complexity and diversity in terms of spore formation and infection of its host. In the spring, the spores germinate and produce specialized structures called uridiniums on young blackberry leaves. These uridiniums release uridiniospore spores that are capable of infecting other leaves and spreading the disease. During the summer, the fungus continues to develop and produces telia, which are durable structures containing teliospores. These teliospores are able to survive adverse environmental conditions and, when the following spring arrives, they germinate to release basidiospores that initiate new infections. The infection cycle is completed when these basidiospores infect the blackberry leaves, allowing the fungus to perpetuate its presence in the crop.