Economic Benefits from Virus Screening: A Case Study of Grapevine Leafroll in the North Coast of California

Abstract

Viruses and related pathogens have no cure and impose high costs on nurseries and specialty crop producers. These diseases are typically spread through infected planting stock and plant propagation material. For some viruses, field spread after planting is also important in determining vineyard health. However, virus spread can be minimized if clean stock is planted. This paper presents the costs and benefits of a virus screening program for Grapevine Leafroll associated Virus-3 (GLRaV-3) in the North Coast region of California. Grower costs and benefits from using GLRaV-3-free vines were computed and extrapolated to the North Coast winegrape industry as a whole. Economic benefits from the GLRaV-3 testing, therapy, and distribution programs were in excess of $20 million/yr for the region and substantially outweighed the costs. The results showed potential benefits from removing and replacing diseased vines, rather than leaving them in the vineyard where they can be foci for disease spread. Significant costs were also associated with disease entering from infected vines on neighboring properties.