RT Journal Article SR Electronic T1 Reducing the Economic Impact of Grapevine Leafroll Disease in California: Identifying Optimal Disease Management Strategies JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 138 OP 147 DO 10.5344/ajev.2014.14106 VO 66 IS 2 A1 Katie D. Ricketts A1 Miguel I. Gomez A1 Shady S. Atallah A1 Marc F. Fuchs A1 Timothy E. Martinson A1 Mark C. Battany A1 Larry J. Bettiga A1 Monica L. Cooper A1 Paul S. Verdegaal A1 Rhonda J. Smith YR 2015 UL http://www.ajevonline.org/content/66/2/138.abstract AB Grapevine leafroll disease (GLRD) is a devastating viral disease found across all grapegrowing regions. Vineyard managers have adopted various strategies for managing GLRD, including roguing individual symptomatic vines and replacing them with certified vines derived from clean, virus-tested stocks; applying insecticides targeting mealybug vector populations to reduce disease spread and minimize long-term impacts; and fully replanting vineyards at the onset of disease symptoms. Moreover, some managers elect not to control GLRD at all. We collected survey data from vineyard managers throughout the three major California grapegrowing counties, Napa, Sonoma, and Northern San Joaquin Valley, to estimate the economic impact of GLRD on Cabernet Sauvignon vines. The goal was to identify cost-minimizing management strategies under various disease-prevalence levels, price penalties, timing of disease onset relative to vineyard age, yield losses, and costs of control. Our results estimated that the economic cost of GLRD ranged from $29,902 to $226,405 per ha. Roguing symptomatic vines and replanting with certified vines in combination with insecticides to reduce mealybugs may minimize losses if GLRD prevalence is low (between 5 and 10%), while a full vineyard replacement should be pursued if disease prevalence is higher, generally above 25%, although regional differences were noted. These findings should help vineyard managers in the three regions examined to adopt optimal GLRD management strategies that can be tailored regionally or locally to unique market opportunities, potential market prices, and annual operating costs.