Identification of sweet potato (Ipomoea batatas L.) viruses in Costa Rica.
A survey for sweet potato (Ipomoea
batatas L.) viruses was conducted in five commercial fields in
Costa Rica from February to May 2002. High percentage of
plants showing virus-like symptoms were observed in three
of the five commercial fields. Graft-inoculations of fieldcollected
samples to the virus indicator plant Ipomoea setosa
were conducted. Foliar samples from inoculated plants were
tested serologically for Sweet potato feathery mottle virus
(SPFMV) and Cucumber mosaic virus (CMV), by reverse
transcription polymerase chain reaction (RT-PCR) for Sweet
potato chlorotic stunt virus (SPCSV), and by molecular
hybridization for Sweet potato leaf curl virus (SPLCV). The
aphid-transmitted SPFMV was the most common virus
detected. Other viruses detected included SPCSV and
SPLCV. CMV was not detected in any of the samples tested.
Mixed infections of SPFMV and SPCSV were detected in the
3 commercial fields with a high percentage of plants showing
virus-like symptoms. The identity of SPCSV was confirmed
by whitefly (Bemisia tabaci) transmissions and RNA analysis
of selected RT-PCR positive samples.