Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus
(TCSV) are two emerging tospoviruses in Florida. In a survey of the
southeastern United States, GRSV and TCSV were frequently detected in
solanaceous crops and weeds with tospovirus-like symptoms in south
Florida, and occurred sympatrically with Tomato spotted wilt virus (TSWV)
in tomato and pepper in south Florida. TSWV was the only tospovirus
detected in other survey locations, with the exceptions of GRSV from tomato
(Solanum lycopersicum) in South Carolina and New York, both of
which are first reports. Impatiens (Impatiens walleriana) and lettuce
(Lactuca sativa) were the only non-solanaceous GRSV and/or TCSV
hosts identified in experimental host range studies. Little genetic diversity
was observed in GRSV and TCSV sequences, likely due to the recent
introductions of both viruses. All GRSV isolates characterized were reassortants
with the TCSV M RNA. In laboratory transmission studies,
Frankliniella schultzei was a more efficient vector of GRSV than F. occidentalis.
TCSV was acquired more efficiently than GRSV by F. occidentalis
but upon acquisition, transmission frequencies were similar. Further
spread of GRSV and TCSV in the United States is possible and detection
of mixed infections highlights the opportunity for additional reassortment
of tospovirus genomic RNAs
