Thrips diversity of cotton ecosystem and the role of parthenium pollen grains in the transmission of tobacco streak virus (TSV) infection in cotton

Survey in the cotton fields of Coimbatore and Erode districts confirmed the presence of three different thrips species including, Scirtothrips dorsalis, Scirtothrips oligochaetus, and Frankliniella occidentalis. Their identity was confirmed through morphometric analysis and molecular characterization. Tobacco streak virus (TSV) was detected in the leaves and pollen grains of both parthenium and cotton plants collected from infected cotton fields. The presence of TSV was confirmed through immuno-detection by direct antigen coating enzyme-linked immuno sorbent assay (DAC-ELISA). Further confirmation was accomplished by reverse transcriptase polymerase chain reaction (RT-PCR) using TSV coat protein-specific primers. Other than parthenium, weed plants in the cotton field such as Trianthema portulacastrum, Boerhavia diffusa, and Amaranthus sp. were also confirmed for TSV infection through RT-PCR. Parthenium hysterophorus plants acts as a silent carrier of TSV and they occasionally produced symptoms. Among all the randomly collected thrips samples, two pooled samples were detected positive for TSV through RT-PCR.

Automated summary

A survey in the cotton fields of Coimbatore and Erode districts confirmed the presence of three different thrips species, as well as the infection of Tobacco streak virus (TSV) in parthenium and cotton plants. Weed plants such as parthenium act as silent carriers of TSV, while other weeds in the cotton fields were also confirmed to be infected with TSV. Two pooled thrips samples were detected positive for TSV through RT-PCR among all randomly collected samples.