Outbreaks of Tomato Chlorotic Spot Tospovirus in Commercial Tomato Fields and Effectiveness of Different Management Measures in South Florida

Abstract

Tomato chlorotic spot tospovirus (TCSV) is an emerging tospovirus in south Florida. TCSV has caused significant damage to tomato production since its discovery in the United States in 2012. Effective measures for managing tomato chlorotic spot (TCS) disease have not been determined in commercial production fields except for planting resistant/tolerant tomato cultivars. In this study, the distribution of TCS in commercial tomato fields was investigated, and the two grower-implemented control measures, the use of resistant tomato cultivars and UV-reflective plastic mulch to repel TCSV vectors, were evaluated for any effect on the incidence of infection or disease when a severe outbreak occurred during the 2018 to 2019 season. A gradient TCS disease was found throughout the field planted with the susceptible cultivar ‘Sanibel’, suggesting a dispersal of the vectors from external sources and the influence of wind direction on disease distribution. Results from the surveys showed that the resistant/tolerant tomato cultivar ‘Red Bounty’ had significantly (P < 0.05) lower infection with TCSV compared with the susceptible cultivar Sanibel on the same type of plastic mulch in adjacent fields. UV-reflective plastic mulch significantly reduced TCS incidence in the susceptible tomato cultivar Sanibel compared with the standard white plastic mulch. This study provided first-hand support for recommendations to effectively manage TCS in tomato fields in south Florida.