Tomato Yellow Leaf Curl Virus ( Begomovirus chohini ) and Tomato Chlorosis Virus ( Crinivirus tomatichlorosis ): An Emerging Threat in Tomato Production in Georgia, USA

Tomato yellow leaf curl disease (TYLCD) is a major constraint to tomato (Solanum lycopersicum L.) production globally, threatening yield and sustainability. Although the United States remains a leading producer, national production has declined, with viral diseases playing a significant role. TYLCD is primarily caused by tomato yellow leaf curl virus (TYLCV), a DNA virus transmitted by the sweetpotato whitefly. Disease severity is further intensified under mixed infection conditions involving TYLCV and tomato chlorosis virus (ToCV), which can induce severe TYLCD-like symptoms and compromise host resistance. Ty-resistance genes introgressed from wild tomato relatives were deployed in commercial cultivars, providing intermediate resistance; however, resistance is often partial and prone to breakdown, particularly under mixed infections. Notably, severe symptoms were observed as early as 3–4 weeks post-transplant, well before flowering and fruit set, posing a substantial risk to commercial tomato production. These findings highlight the limitations of current resistance strategies and emphasize the urgent need for integrated management approaches to address evolving virus-vector-host interactions.