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Brown or black spotting and curling of leaves is a sign of fireblight
Fireblight

Outbreak of tree disease declared in Grande Prairie

Jul 25, 2019 | 5:30 AM

Homeowners in Grande Prairie that have apple, crabapple, pear, hawthorn or mountain ash trees should be on the lookout for fireblight disease.

An outbreak of the disease has been declared by the City due to the very wet conditions we have experienced over the last few weeks, followed by warm temperatures. What those conditions then do is essentially re-invigorate a disease that is already living within the tree, says Integrated Pest Management Coordinator with the City, Amy Needham.

“All it’s waiting for is the proper environmental conditions,” said Needham. “So, it’s generally only in the years where we have this kind of warm, rainy weather throughout May and June that we get outbreaks.”

The disease typically affects fruit trees, not ones that you might find around Muskoseepi Park or in forested areas around Grande Prairie. However, there are still many trees that could face infection around the city that Needham and her team are looking for every year.

Typical signs that your tree may be infected include:

  • Flagging or dead spots on new growth that turns black or browns (often curled)
  • Sunken cankers spreading down shoots and branches in front of the dying leaves
    Photo of a tree infected with fireblight (Photo: City of Grande Prairie)

Fireblight spreads very quickly from tree to tree and can kill a tree within a single season. With that, those with the above listed types of trees need to be on the lookout for the disease.

“It’s a simple matter of pruning out the infection, 12-18 inches below where the active infection is occurring and disposing of it in the garbage so you don’t keep the wood around where it is going to cause it to be kept in your yard,” said Needham.

Needham also recommends that when pruning infected trees, to disinfect the pruning tool after each cut to help stop the spread to other parts of the tree.

Also, to help slow the spread of the disease, Needham recommends property owners have a variety of trees on their property.

“I always tell people that every tree has it’s things that it gets. I mean, if you want something in your yard that is never going to get an insect or a disease, then you’re pretty much looking at just a big rock,” said Needham. “But having a lot of diversity and having lots of different species of trees in your yard will help buffer against stuff like this.”

More information on fireblight and other plant diseases can be found on the City’s website.