INCIDENCE OF MAJOR STRAWBERRY VIRUSES IN NORTH AMERICA

In the last decade there has been a coordinated effort to develop detection protocols for all strawberry viruses. This effort has yielded sensitive protocols for all major strawberry virus groups including those transmitted by aphids, whiteflies and pollen. Those tests where employed to determine the presence of strawberry viruses in major production areas of North America. The viruses evaluated were: Strawberry Crinkle, Mottle, Mild yellow edge, Vein banding, Chlorotic fleck, Pallidosis, Necrotic shock, Fragaria chiloensis latent, Apple mosaic and Beet-pseudo yellows. The aphid-borne viruses were predominant in the Pacific Northwest (Oregon, Washington and British Columbia) whereas the whitefly transmitted viruses were prevalent in California, the Midwest (including Ontario) and Northeast (northeastern U.S. and southeastern Canada). The incidence of pollen-borne viruses is low in most areas with Necrotic shock being the most prevalent virus of the group. These results indicate that there are hotspots for individual virus groups that normally coincide with the presence of the vectors although there are exceptions, such as that of the whitefly-transmitted viruses in the Northeast, indicating that some of the viruses may be moving though the propagation material.