The Canadian Food Inspection Agency’s plum pox virus survey this year turned up a “significant drop” in positive samples, despite substantially more samples collected.
CFIA reported Thursday it collected just over 750,000 samples fom susceptible tender fruit plants in 2008, up about 35 per cent from 2007, but this year only found 131 positives, down from 261 in 2007.
However, the agency also found a new strain of plum pox in three trees within the plum pox quarantine area around Grimsby, Ont. The new “PPV-Rec” strain was discovered relatively recently and seen only in Europe.
Preliminary research suggests it might have been transferred here by aphids but the specific host range of this strain still needs to be determined, CFIA said. “At this time, very little is known about the biology of the strain.”
The three positive trees in this case were plum rootstocks with grafted apricot, peach and plum branches. The homeowner had checked the trees and contacted CFIA.
The federal government last fall announced a four-year, $45.6 million program, funding both CFIA surveillance and financial aid to Ontario fruit producers whose crops were affected by PPV. The Ontario government also provided a share of funding for the 2007 season.
The federal government announced in May that the area of Stoney Creek, Ont. has been removed from the list of areas infected with plum pox virus.
Another new strain (PPV-W) was discovered at a residence in Stoney Creek in 2002, CFIA said. Survey activities were stepped up in that area and no further positives were found. The infected tree was removed and that strain type was never detected again in Canada.