The recent wet weather has caused an outbreak of fireblight disease in Grande Prairie’s urban forest.

Fireblight is legislated under the Agricultural Pests Act of Alberta and must be controlled wherever found.  It affects apple, crabapple, pear, hawthorn and mountain ash trees.  This disease spreads extremely quickly and may kill trees in a single season if left untreated.

The City of Grande Prairie is asking residents to watch their apple, pear, hawthorn and mountain ash trees for symptoms and treat them immediately if found. 

To check if your tree has contracted fireblight disease, watch out for the following symptoms:

• Sudden flagging and death of new growth, often black/brown and curled.  
• Sunken cankers spreading down shoots and branches in front of the dying leaves.

To treat infected trees:

• Prune out all infected branches 12-18 inches below the infection.
• Disinfect the pruning tool in between each cut with gas line antifreeze or a 10% bleach solution to avoid spreading the disease further throughout the tree.

Over 10% of the City’s public tree inventory is susceptible to fireblight.  Parks Operations staff are inspecting and treating all city-owned apple, crabapple, pear, hawthorn and mountain ash trees throughout the summer to curb the spread of infection and again this winter to remove overwintering cankers.

For more information on fireblight, visit the fireblight page under “Plant Diseases & Fungi” on the City website.