Thrips-vectored viruses turn up in scattered tomato fields

01/08/2013 11:32:00 AM
Vicky Boyd

A survey of 500 fields in eight other Southeastern tomato-producing states this summer did not detect GRSV, he says.

Florida remains the only state in which the virus is found.

Glades Crop Care plans to conduct trials this spring to study how the disease spreads within a tomato field, Frantz says.

In South America and Africa, GRSV infects not only Solanaceous plants—which include tomatoes, peppers and eggplants—but also legumes, such as peanuts.

A survey of Florida’s peanut acreage near Lake Okeechobee was conducted this summer, and none of 80 to 85 samples collected was positive for GRSV, Adkins says.

“We looked at other plants that showed similar symptoms and only found tomato spotted wilt virus, which was a surprise to us,” Adkins says. “And we only saw GRSV on solanaceous plants.”

Further genetic testing showed what scientists were calling GRSV in Florida actually was a hybrid that had genetic material from true groundnut ringspot virus as well as tomato chlorotic spot virus, or TCSV.

That might explain why the survey didn’t detect it in peanuts, Adkins says.

A new tomato virus

Until last spring, TCSV was known to occur in Argentina and Brazil but not in Florida, Jane Polston, a University of Florida plant pathologist in Gainesville, told attendees of the recent Florida Joint Tomato Conference.

But that has since changed.

Polston says she received 15 samples collected from Miami-Dade County on March 15 and 12 collected from Lee County April 12—all showing leaf necrosis.

Three different tests were used to pinpoint the culprit.

Immunostrips from Agdia can quickly confirm the presence of a tospovirus, but she says they won’t differentiate the species.

Polston then turned to PCR, a type of genetic fingerprinting, to try to narrow the organism’s identity.

To confirm her results, she sequenced the newcomer and compared the results to known viruses in the gene bank.

The verdict: TCSV.

It has since turned up in Hendry and Collier counties, Adkins says.

In South America, TCSV has been reported to have a host range that includes vegetables and ornamentals. Among them are peppers, tomatoes, tobacco, jimson weed and ornamental tobacco.

Both western flower thrips and flower thrips are known to spread TCSV in South America, she says.

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