First record of the transmission of groundnut bud necrosis virus (GBNV) in tomato by Southeast Asian thrips, Thrips parvispinus.

The invasive thrips species, Thrips parvispinus, was identified infesting tomato crops at three locations across Tamil Nadu during 2022-2023. The pure population density of T. parvispinus showed a strong positive correlation with GBNV incidence, with the highest infestation observed at Devarayapuram (Coimbatore), where an average of 2.4 thrips per plant coincided with a 41.0% disease incidence. Molecular identification through mtCOI sequencing confirmed 99-100% identity with T. parvispinus sequences from India, whereas RT-PCR analysis of field collected adults revealed 100% identity with the GBNV isolate infecting groundnut (EF179100). During transmission studies on cowpea, first instars acquired the virus, whereas adults transmitted it efficiently after a 72 h acquisition access period, with a 2.7 × 106 N gene copy number and the highest OD value (1.98) in DAC-ELISA, with 73.33% transmission efficiency. A  72 h inoculation access period yielded the highest transmission efficiency (86.66%), with 1.1 × 107 N gene copies and an OD value of 1.89. Characteristic necrotic spots appeared on cowpea leaves 10 days post release, developing into chlorotic rings by day 13. Even a single adult thrips was capable of transmitting GBNV, although the efficiency increased with vector density, peaking at 86.66% with 10 thrips per plant. In tomato, symptom expression intensified with increasing thrips density, with yellow to blackish spots appearing by 15th day, which progressed to necrotic rings by 20th day (2.8 × 107 copies). This study provides the first experimental evidence confirming T. parvispinus as a vector of GBNV in tomato, emphasizing its epidemiological significance and the need for vigilant monitoring within integrated virus management programs. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-025-04615-9.