Black Currants

As a crop, the blackcurrant suffers from several pests and diseases. The most serious disease is reversion, caused by a virus transmitted by the blackcurrant gall mite. Another is white pine blister rust which alternates between two unrelated hosts, one in the genus Ribes (blackcurrant included) and the other a white pine. This fungus caused damage to forests when the fruit was first introduced into North America, where the native white pines have no genetic resistance to the disease. As a result, the blackcurrant has for most of the 20th century been subject to restrictions in parts of the United States as a disease vector. The effectiveness of these restrictions is questionable, since other Ribes species also host the disease and are native to North America.