Surveys of tomato production areas will begin this fall in South Florida and move up the Atlantic coast next year with the tomato season, Adkins says.
A similar survey will be conducted in Southeast peanut production areas, including the several hundred acres around Lake Okeechobee grown mostly for the boiled peanut market.
From South Africa to South America to Florida
When GRSV was confirmed in the Homestead area in 2009, it marked the first time the disease had been found in the United States.
It is native to South Africa, where it causes stunting of the peanut plant and small, distorted leaves with severe yellowing and concentric ringspots. GRSV also has been identified in tomatoes in Brazil and Argentina during the 1990s.
One of the challenges is very little has been written about GRSV in literature, so researchers have very little to go by, Adkins says.
Since the initial discovery in Miami-Dade County, GRSV has been found in tomato fields in Collier, Hendry, Lee, Manatee, Martin and Palm Beach counties.
In addition, it has been found in pepper, eggplants and tomatillo in peninsular Florida from Manatee County south.
Based on grower and scouting reports in 2010, sporadic infections were seen throughout south Florida’s tomato production area at low levels, typically 2 percent to 3 percent, Adkins says.
How wide a host range the virus has is one area in which the researchers hope to gain more knowledge.
Tomatoes, peppers, eggplants and tomatillo are members of the Solanaceous family whereas peanuts are members of the legume family.
Host plants can be infected during any growth stage.
During the 2010 season and again this year, infected plants were also found in greenhouses, Adkins says.
When tomato plants are infected in the seedling or plug stage, they typically die before reaching the field he says. Frequently, GRSV symptoms are very similar to those of tomato spotted wilt virus, Adkins says.
If tomato plants are infected at an early stage, symptoms include inward rolling leaves, leaf bronzing and dark brown leaf flecking.
As the infection progresses, brown streaks form on the main stem and leaf petioles, and wilting or death occurs in the top portion of the plant. Fruit may be deformed, show uneven ripening and may have raised bumps or rings.
But if you see necrosis on tomato stems, there’s a good chance it’s GRSV, Adkins says. In other crops, such as peppers and eggplants, the symptoms are visually nearly identical to TSWV.