Virus that poses 'serious threat' to Niagara stonefruit detected in area, prompting federal agency response

Canada's food regulator is taking action to prevent the spread of a virus affecting fruit trees after it was detected in the Hamilton and Niagara area for the first time since 2013. 

On its website, the Canadian Food Inspection Agency (CFIA) says plum pox virus (PPV) can "drastically reduce" yields of plants including peaches, nectarines, plums, apricots, cherries and almonds. The Niagara Region is known for its stonefruit, with Tourism Niagara boasting the region grows more than 80 per cent of Canada's peaches.

PPV "is a serious threat to Canada's tender fruit, fruit processing and nursery industries," the CFIA said in a Feb. 24 news release.

Since 2011, the CFIA has monitored and managed the virus, which doesn't harm people but negatively affects stonefruit trees.

In 2013, CFIA established a "regulated area" which includes the northern part of Niagara bordering Lake Ontario and part of east Hamilton. In the regulated area, it's forbidden to move and grow plants that host the virus.

In spring and summer, inspectors monitor and take samples from trees near the border on both sides of the regulated area. Over 10 years passed without a detection, which was "a really good sign controls were working," said Chris Balardo, a CFIA inspection advisor based in St. Catharines, Ont. CFIA last detected the virus in the region in 2013.

But this past summer, Balardo said, inspectors detected two new infestations in Stoney Creek within the Hamilton part of the regulated area. In response, CFIA expanded part of that zone by an additional 2.5 kilometres. 

The new detections are "definitely concerning," Balardo said. The hope is that extending the area with restrictions will "slow down any future spread."

Inside the regulated area, people are not allowed to move potentially infested materials, including young branches with buds and young plants grown in nurseries. 

Growers within the zone must source new trees from outside the zone or CFIA-approved growers to ensure they're not spreading the virus, Balardo said. 

Inspectors monitor for the virus by sampling leaves from trees on orchards and private property. Balardo said this year, his team will be doing regular surveillance in the area where the virus was detected last year. 

In addition to protecting domestic trees, regulating PPV is a necessary part of maintaining access to the United States fruit market for Canadian growers. 

No treatment for PPV

Identified in Bulgaria, PPV was first detected in Ontario and Nova Scotia in 2000 and Pennsylvania in 1999. It no longer exists in the eastern province or United States. The Niagara-Hamilton area is the only PPV regulated zone in Ontario. 

Aphids can spread the virus between trees and it also spreads when people propagate new plants using infected plants, hence the restrictions on propagation.

Ring-like spots on leaves and fruit can be a symptom of the virus, but it can be most reliably detected by tissue samples, CFIA says. There is no treatment for PPV, so the most effective way to prevent an infected tree from spreading is to remove the tree and its roots. 

Balardo said he wants people to know CFIA inspectors will be in the field during growing season and available if people have questions. He added people can report sightings online. 

It's "really, really important to help protect Canada's industry and the environment," he said.