Plum Pox Virus in Canada Blake Ferguson Canadian
Plum Pox Virus in Canada Blake Ferguson Canadian Food Inspection Agency
Plum Pox Virus • Plum Pox Virus (PPV) is a virus that infects plants in the genus Prunus - plums, peaches, apricots etc. • It causes a disease called plum pox or sharka. • Plum Pox is the most serious disease of stone fruits in Europe. • The virus has several strains : D, M, C, W and EA strains.
Distribution in the World • First found in Bulgaria around 1917 • Now present in most European countries – widespread in central & eastern Europe – recently reported in Mediterranean countries – sporadic reports in northern Europe • Also in Egypt, India, Syria, Turkey, Argentina & Chile • 1999 - Pennsylvania, USA, strain D • 2000 – Canada, strain D
Background • Plum Pox Virus (Sharka) • Decrease yield & fruit quality • Transmitted via aphids or propagation • Transmissibility and host range vary by strain • Severe economic impact
Host Range • Hosts are mainly in the genus Prunus • Both fruit stock and ornamental plants may be infected • PPV affects plums, peaches, nectarines, almonds, cherries and apricots • Wild Prunus species are also hosts • Some herbaceous weeds can be infected
Stone Fruit Production in Canada’s Commercial Production of PPV-D susceptible stone-fruit • • Ontario British Columbia Nova Scotia Quebec 77% 21% 1. 1% 0. 6%
PPV survey in Canada 2005
(2004) (2003)
24 Positives on 19 Properties (2 properties not shown on map) St. Catharines = 2004 Survey = 2005 Survey = Positive Samples
Total Ontario Samples Collected 1, 041, 442
Positive Blocks - Ontario % infested blocks 2000: 246/5121 4. 80 % 2001: 211/6125 3. 44 % 2002: 215/7474 2. 88 % 2003: 235/7911 2. 97 % 2004: 302/8158 3. 70 % 2005: 168/7293 2. 30%
Positive Blocks - Ontario
Total positive blocks Total positive trees Number of samples collected
Aphid transmission of PPV 2004 evidence – Volunteer seedlings found to be infected – Newly planted blocks propagated from PPV-tested budwood have been found to contain infected trees – Research indicates peach to peach transmission rates as high as 22% using 50 Myzus persicae aphids per plant 2005 evidence – 5 residential trees grown from seed were found positive – 103 existing orchard blocks becoming positive after 4 -5 years of negative testing.
Niagara Repeat Positive Blocks * In at least one subsequent year. **51% of positive blocks are repeat positives in subsequent years.
Current challenges • • Continuing discovery of newly positive blocks Availability of tested/certified replacement trees Clearer data needed on aphid spread of PPV Resistance of growers to mandatory block removals • Need to consider buffers but – logistical difficulties – industry structure considerations – neighbour effect
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