New, 24-Hour Test for Tomato Virus

Tomatoes infected with a newly described virus, tomato chlorosis, should now be easier to diagnose, according to virologists with Agricultural Research Service.

The virologists developed a test that determines within 24 hours whether a plant has the virus. It’s transmitted by four species of sap-sucking whiteflies, major pests of tomatoes and other crops.

The University of Florida's plant disease clinicin Gainesville is now using the ARS test on leaf specimens sent by growers. Florida produces more than a third of the nation's $460 million tomato crop. The Florida clinic’s researchers will also use the new test to identify weed species that are vulnerable to the virus. Whiteflies may be carrying virus from those weeds to nearby tomato fields.

The test relies on molecules, called nucleic acid probes, that detect the virus’ genetic material. These are the first such probes for this virus.

ARS scientists and their clinic colleagues were the first to describe and name the tomato chlorosis virus. It causes leaves to yellow and thicken, and plants to produce fewer and smaller fruit. The ARS tests indicate that greenhouse, banded-wing, sweetpotato and silverleaf whiteflies all can transmit the virus.

From Jan. 28 to 30 in San Diego, scientists are meeting for their fifth annual review of progress under a national five-year research and action plan against the silverleaf whitefly.

Scientific contact: James E. Duffus/Gail C. Wisler, U.S. Agricultural Research Station, Salinas, CA (408) 755-2835