Association of a tospovirus with necrosis disease-affected sunflower sample
s collected from Bangalore, Dharwad and Hyderabad was established on the ba
sis of immuno- and bio-diagnosis. The virus induces necrosis on leaves foll
owed by necrosis on petioles, stems and floral calyx, The virus was mechani
cally transmitted to cowpea, a diagnostic assay host for tospovirus. The su
nflower tospovirus, tentatively referred to as sunflower necrosis virus (SF
NV), showed positive serological relationship with groundnut bud necrosis v
irus (GBNV) and watermelon silver mottle virus (WSMV) in direct antigen-coa
ted (DAC)-ELISA using polyclonal antisera directed against nucleocapsid pro
tein. The exact identity of the virus remains to be determined.