Tomato Spotted Wilt Virus (TSWV) in India: Epidemiology, Thrips-Mediated Transmission, Molecular Interactions and Integrated Disease Management

Abstract

Tomato spotted wilt virus (TSWV), a member of the genus Orthotospovirus (family Tospoviridae), is one of the most destructive viral pathogens affecting vegetables, legumes, and ornamentals in India. The virus has a wide host range, including tomato, chilli, groundnut, and several weed species, which act as reservoirs and play a critical role in disease epidemiology. TSWV is transmitted in a persistent propagative manner by thrips, mainly Thrips palmi, Frankliniella schultzei, and Scirtothrips dorsalis, which are widely distributed across Indian agro-climatic zones. Virus acquisition occurs during the larval stages, followed by replication and transmission by adults. Molecular interactions between TSWV proteins and thrips midgut and salivary gland tissues govern virus replication, movement, and vector competence. In host plants, TSWV suppresses RNA silencing pathways and alters defense signaling, resulting in severe symptoms and significant yield losses. Integrated disease management of TSWV in India relies on a holistic approach involving early diagnosis, vector population management, use of resistant cultivars, and removal of alternate hosts, reflective mulches, and judicious insecticide application. Understanding virus–vector–host molecular interactions, combined with sustainable management practices, is crucial for long-term control of TSWV under Indian conditions.