Multi-Year Trials Show Trends in Incidence of Tomato Spotted Wilt in Select Peanut Cultivars in Alabama

One problematic disease of peanut in southeastern United States is tomato spotted wilt, caused by tomato spotted wilt orthotospovirus (TSWV). Tomato spotted wilt became widespread in peanuts across the southeastern United States in the early 1990s, but cultivars resistant to TSWV were subsequently released and have greatly reduced losses due to this disease. However, in recent years, tomato spotted wilt incidence became substantial, even in resistant cultivars such as Georgia-12Y. Cultivar trials, done annually in Alabama, provided data with which to evaluate tomato spotted wilt incidence over several years and consider if TSWV is overcoming resistance in Georgia-12Y. The multi-year trials also allowed comparison of disease and yield responses of root-knot resistant cultivars, Georgia-14N and TifNV-High O/L, to commercial standard cultivars, Georgia-06G and Georgia-09B. While tomato spotted wilt incidence was greater in 2020, 2021, and 2022 than in earlier study years, incidence of the disease in Georgia-12Y was lower than on other cultivars in each year. Pooled over years, pod yields of Georgia-06G and Georgia-12Y were similar and greater than yields of other cultivars. In five and three of seven years, TifNV-High O/L and Georgia-14N, respectively, had yields that were similar to Georgia-06G. Yields were negatively correlated to disease incidence (R = -0.56) over all cultivars and positively correlated to rain (R = 0.75). No link was found between several weather variables and intensity of tomato spotted wilt in this study. While disease incidence was substantial in the three most recent years examined, disease resistance exhibited by Georgia-12Y appears stable.