An Agent-Based Computational Bioeconomic Model of Plant Disease Diffusion and Control: Grapevine Leafroll Disease

Abstract

Grapevine leafroll disease threatens grape harvests in the United States and around the world. This viral disease reduces yield, delays fruit ripening, and affects wine quality. Its spatialdynamic diffusion process remains poorly understood and little is known about profitmaximizing control strategies. In this article, we model the disease spatial-dynamic diffusion in a vineyard, evaluate nonspatial and spatial control strategies, and rank them based on expected net present values. Nonspatial strategies consist of roguing and replacing symptomatic grapevines with and without considering vine age. In spatial strategies, symptomatic vines are rogued and replaced, and their nonsymptomatic neighbors are virus-tested, then rogued and replaced if the test is positive. We find that age-structured strategies outperform their nonage-structured counterparts. More importantly, we show that spatial strategies dominate nonspatial strategies, increasing the vineyard expected net present value by 40 percent relative to the baseline of no control.