Mitigating the Economic Impact of Grapevine Red Blotch: Optimizing Disease Management Strategies in U.S. Vineyards

Abstract

Grapevine red blotch disease (GRBD) is a recently recognized viral disease found across some the major grape-growing regions in the United States. Vineyard managers were surveyed to (i) estimate the economic impact of GRBD on Vitis vinifera cv. Cabernet Sauvignon in Napa and Sonoma Counties in California and on V. vinifera cv. Merlot in Eastern Washington State and Long Island in New York State, and (ii) identify cost-minimizing management strategies under various disease incidence rates, price penalties for suboptimal fruit composition, timing of disease onset relative to vineyard age, and costs of control. The economic cost of GRBD was estimated to range from $2,213 per hectare in Eastern Washington when disease onset occurs at a low initial infection level and low price penalty to $68,548 per hectare in Napa County when faced with a high quality penalty and high initial infection. Our results further suggested that roguing symptomatic vines and replanting with clean vines derived from virus-tested stocks minimize losses if GRBD incidence is low to moderate (below 30%), while a full vineyard replacement should be pursued if disease incidence is higher, generally above 30%. These findings should help vineyard managers in the four viticultural regions examined to adopt optimal GRBD management strategies.