Expanding Field of Strawberry Viruses Which Are Important in North America

Strawberry production is increasing annually, with the world production exceeding 4 million tons. Virus diseases of strawberry are also increasing as the crop is planted in new regions and exposed to new viruses. A decade ago there were about a dozen viruses known to infect strawberry. There are now seven known aphid transmitted viruses—Strawberry crinkle, Latent C, Mottle, Mild yellow edge, Pseudo mild yellow edge, Vein banding, and Chlorotic fleck. Whitefly transmitted viruses have become more important; four criniviruses and one geminivirus have emerged as new threats to strawberry in areas where vectors are present. The ilarviruses that infect strawberry include Strawberry necrotic shock (previously misdiagnosed as Tobacco streak), Tobacco streak, Fragaria chiloensis latent, and Apple mosaic viruses. Strawberry necrotic shock is the predominant ilarvirus in the United States, whereas Fragaria chiloensis latent has significant presence in Chile. Modern strawberry cultivation has minimized the impact of nematode transmitted viruses but the elimination of methyl bromide may lead to the reemergence of this virus group in the future. With the knowledge we have acquired over the last decade, it is now possible to have robust certification systems, the cornerstone for minimizing the impact and spread of strawberry viruses.