First report of tomato torrado virus on weed hosts in Spain.
To identify possible alternative hosts that may serve as reservoirs for Tomato torrado virus (ToTV), samples of 72 common weed species were collected from greenhouses in Murcia and the Canary Islands, Spain, where torrado disease symptoms were observed in tomatoes. Forty-seven showed virus-like symptoms and 25 were asymptomatic. Symptoms included mild mosaic, blistering, vein clearing, interveinal yellowing, yellow spots, necrosis, leaf distortion and curling. Samples were analysed by RT-PCR using primers specific for ToTV. Twenty-two of the 72 weed samples belonging to Amaranthus sp., Spergularia sp., Atriplex sp., Chenopodium ambrosioides, Chenopodium sp., Halogetum sativus, Senebiera didyma, Malva sp., Polygonum sp., Nicotiana glauca and Solanum nigrum were positive for ToTV by molecular hybridization and RT-PCR. This is thought to be the first report of natural infection of weeds by ToTV.