The seasonal detection of strawberry viruses in Victoria, Australia

PCR tests were adopted from international, peer-reviewed literature and developed for the detection of Strawberry mottle sadwavirus (SMoV), Strawberry crinkle cytorhabdovirus (SCV), Strawberry mild yellow edge potexvirus (SMYEV), Strawberry vein banding caulimovirus (SVBV), Beet pseudos yellows crinivirus (BPYV), and Strawberry pallidosis associated crinivirus (SPaV) in Victoria, Australia. The PCR tests were applied to 23 positive control plants infected with one or more viruses and these plants have been tested monthly from May 2005 to April 2007. Our results have indicated that the viruses were most reliably detected by PCR during May-October. In November, December and January of each year a decline in the number of positive PCR results for BPYV, SVBV and SPaV was observed. Twelve positive control plants maintained at the AQIS post entry quarantine screenhouse at Knoxfield, Victoria, and also infected with one or more viruses, were tested monthly from August 2006 to April 2007. A similar decline in the ability to detect SMoV, SVBV and SPaV in the AQIS positive control plants was observed in 2006/07 and November was the least reliable month for detection of strawberry viruses in these plants. These results indicate that spring and autumn may be the optimal times for PCR detection of strawberry viruses in south east Australia.