A tomato disease that ravaged crops in the Caribbean and Florida has arrived in Georgia, and growers here wish it had stayed south of the border.
The disease is caused by the tomato yellow leaf curl virus (TYLCV). In the United States, the virus was first reported in Dade County, Fla., in July 1997. It established quickly, and Florida tomato growers soon began to feel its impact.
New to the U.S., but not to the Middle East
TYLCV has been present in Israel for more than 40 years. It showed up in Cuba, Jamaica and the Dominican Republic in the early '90s.
"The virus is transmitted by sweet potato and silverleaf whiteflies," said Hanu Pappu, a plant pathologist with the University of Georgia College of Agricultural and Environmental Sciences. "Infected plants suffer severe stunting and produce virtually no fruit."Other symptoms include yellowing along the leaf edges and upward cupping of the leaf -- hence the name.
Hurts Tomatoes the Most
"The virus could affect a wide range of plants. But tomato is one of the primary crops affected," Pappu said. "Recently, there was a report from Mexico that pepper plants are also susceptible."
Pappu and other CAES plant pathologists have been expecting TYLCV to cross into Georgia.
"The disease is well established in Florida, and the whitefly population has been building up," he said. "It was only a matter of time before the virus showed up here."
Hit Decatur County First
In the fall of 1998, infected tomato plants were reported in Decatur County, Ga. "The disease was estimated at 1 percent then," Pappu said. "By fall 1999, it was reported in Grady, Colquitt and Tift counties, with some fields in Grady County being 15-percent infected."
At the Coastal Plain Experiment Station in Tifton, Ga., researchers have found infection ranging from 15 to 90 percent in experimental field plots.
If growers notice symptoms in their fields, Pappu said, they shouldn't assume it's TYLCV.
Symptoms Don't Always Mean You've Got TYLCV
"The virus causes distinct symptoms, but other tomato-infecting gemini viruses produce similar symptoms," he said. "A DNA-targeted method must be used to see whether it's TYLCV."
Growers should contact their county Extension Service agent for more on identifying and treating TYLCV.
"It's impractical to completely eradicate the virus," Pappu said. "But a combination of production practices may minimize its impact. These include planting disease-free transplants, removing infected plants early in the season and managing whiteflies with insecticides."
In the future, growers could choose to plant TYLCV-resistant varieties.
"Scientists in Israel are working to breed new resistant varieties," Pappu said. "Here in Georgia, we're continuing to monitor the disease situation closely, and we're conducting research to better understand and control it."
(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)