Scientists have confirmed two new viruses in Georgia's $75 million crop of sweet Vidalia onions.
Stephen Mullis, virology coordinator for the University of Georgia Extension Service, said he's examined about 3,000 Vidalia samples since October and has identified two previously unknown viruses in the crop: tomato spotted wilt and Iris yellow spot.
Scientists say it may take several growing seasons to determine the full impact of the germ attack. Both viruses are spread by tiny insects, known as thrips that infect plants when they bite into them.
The most common thrips in Georgia are tobacco thrips and western flower thrips. Now there's a third, onion thrips, believed to have come in on Peruvian onions imported during the off-season by Vidalia growers.
Plant viruses pose no threat to humans, but they hamper growth and weaken the plants they attack, making them susceptible to other diseases. Diseased onion plants have small yellow lesions on their leaves.