Expert to provide update after 'worst tomato virus' hits California

July 19, 2007

Robert Gilbertson, plant pathology professor at the University of California, Davis, will provide the update on the status of Tomato yellow leaf curl virus (TYLCV) after it was found for the first time in California. The update is part of a news conference on plant diseases that are of importance to California's economy and agriculture, to be held Monday, July 30 at 11 a.m. PST at the Town and Country Resort and Convention Center in San Diego, CA.

In March 2007, the destructive virus was detected in tomato plants and whiteflies from a greenhouse in California's Imperial Valley. Tomato yellow leaf curl virus is distributed primarily by the whitefly, Bemisia tabaci. It spreads quickly from plant to plant within minutes; especially if the whitefly population is high.

"This is undeniably the worst tomato virus there is," said Gilbertson. In other areas where the virus is present, yield losses as great as 100 percent have been reported. This disease poses a significant threat as California is one of the main producers of processing and fresh tomatoes in the United States.

The telltale sign of TYLCV is the yellowing and upward curling of the leaves. As the virus progresses, the plant becomes stunted and it causes the flowers of the tomato plants to die and fall off, rendering the plant unable to produce fruit.

The good news is that the whitefly that carries the virus does not do well in colder areas, such as in Northern California, the state's primary tomato growing area. "This gives us hope that we have this under control, but when the worst tomato virus gets introduced in the California, it is a serious issue. "We are fortunate that we caught it as soon as we did," Gilbertson said.

Plant pathologists are continuing to monitor for the virus and ask all tomato growers, from backyard gardeners to commercial growers, to look for symptoms of the virus. A flyer showing symptoms of the virus is available at www.ipm.ucdavis.edu/PMG/r783103311.html. If symptoms are detected, growers are asked to send samples to their local University of California Cooperative Extension office for testing. If the virus were to spread and become established within the state, management strategies such as planting resistant varieties and implementing tomato-free periods can be implemented to minimize the virus' impact.

Source: American Phytopathological Society