Survey and Indexing of Weeds Growing around Potato Fields for Their Role as an Inoculum Source for Potato leafroll virus (PLRV)

A survey and indexing studies was carried out on weeds plants growing around potato fields to identify their role as an inoculum source for Potato leafroll virus (PLRV). Symptomatic and asymptomatic foliage samples of 26 weed species were collected and tested by DAS-ELISA and RT-PCR. Out of 783 samples tested, 132 samples showed positive reaction with PLRV antisera. RT-PCR was performed on ELISA positive samples to confirm the results. 110 samples showed amplification of desired band revealing PLRV infection. Weed plants tested positive for PLRV in indexing studies were Amaranthus viridis (4), Chenopodium album (19), Datura stramonium (10), Physalis minima (10), Solanum nigrum (56) and Withania somnifera (12). Results of the study indicated that among the six susceptible weed host plants detected, two weed species (C. album and S. nigrum) were abundantly growing and acting as important host plants and source of PLRV inoculum in potato growing regions of the present study. These weeds were found growing frequently in vacant fields and wastelands along roadsides and railway tracks near potato growing regions. Colonies of green peach aphids responsible for transmission of virus were observed on host plants infected with virus. Eradication of weed host plants from unused/waste lands bordering potato fields would be helpful in effective management of PLRV infection in potato.