Orthotospoviruses belong to the family Tospoviridae (order: Bunyavirales) and genus Orthotospovirus. Viruses from this family were generally called “bunyaviruses.” Thus, in order to avoid further misstatement, in 2002, the Bunyavirus genus was renamed Orthobunyavirus (Calisher 2008). Therefore, the Bunyaviridae family was characterized as the largest RNA virus family, classified into five genera: Orthobunyavirus, Hantavirus, Nairovirus, Phlebovirus, and Tospovirus (Abudurexiti et al. 2019; Zerbini et al. 2023). All five genera formerly in the family Bunyaviridae (Hantavirus, Nairovirus, Orthobunyavirus, Phlebovirus, Tospovirus) are now novel viral families, some of which have been combined. The name Bunyaviridae was derived from Bunyamwera in Western Uganda, where the prototype bunyavirus of the same name was isolated. They have some common features and biological properties. Members belonging to the genus Orthotospovirus infect different plant species worldwide. The Orthotospovirus genus is composed of 28 virus species approved by the ICTV and a few tentative species (ICTV 2024.v2 Taxonomy Release) (Table 32.1). Earlier, the taxonomic descriptions of this family were described as genus Tospovirus (family: Bunyaviridae) as per the ninth ICTV report. The occurrence of the tomato spotted wilt disease was first time recorded in 1919 in Australia (Brittlebank 1919). Later, during the 1930s, the tomato spotted wilt virus (TSWV) was identified as the causal virus with the wilt disease (Best 1968). Likewise, it was evidenced that the thrips (Thrips tabaci) transmits the virus in a persistent manner. Acquisition of this virus in thrips occurs during the larval stage and continues till the end of the life cycle of adult thrips (Sakimura 1963). The transmission of orthotospoviruses is governed by different thrips species worldwide. Earlier, virions having spherical enveloped particles were observed in the lumen of the endoplasmic reticulum of plants (Best and Palk 1964). The purified virus was found to contain lipids (Best and Katekar 1964). Subsequently, by electron microscopy, the purified virus particles were observed (Van Kammen et al. 1966), and the architectural compositions were determined (Mohamed et al. 1973). Van den Hurk et al. (1977) based on the virus purification and analyses of the TSWV genome suggested a tripartite RNA. Later, the S and M RNA genome sequences revealed the ambisense strategy of gene expression (de Haan et al. 1990), and subsequently, the L (large) RNA was investigated and found to have a major role in encoding RNA-dependent RNA polymerase (RdRp) (de Haan et al. 1991). Likewise, the M RNA genome sequence information was generated (Kormelink et al. 1992; Tsompana et al. 2005).