Plum Pox Virus, also known as Sharka, was found in fruit trees in Ontario and Nova Scotia as a result of surveying done in 2000 by the Canadian Food Inspection Agency. This was the first known discovery of plum pox virus in Canada.

Plum Pox Virus is a serious plant disease infecting stone fruit species of the genus Prunus including peaches, nectarines, plums, apricots, almonds and ornamental varieties. Plum Pox Virus does not kill trees, but can drastically reduce yields. Plum Pox Virus is transmitted from infected trees by aphids or by grafting or budding. Plum pox virus does not affect human or animal health.

The red zones shown on the map indicate the areas regulated for the Plum Pox Virus within the Province of Ontario for 2005. The regulated areas include areas near Blenheim, Fonthill, Niagara and Stoney Creek.