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Fire Blight: The Tenth and Final Entry in a Series on Edmonton Tree Threats

In this, our tenth and final piece on Alberta tree dangers, we will be looking at a tree disease notorious in Northern and Central Alberta, but that also represents a danger to homeowners in Edmonton as well. Alberta Fire blight is a declared pest under the Province of Alberta’s Agricultural Pest Act, which means that homeowners in Edmonton are responsible for the control of this pest on their property.

While your rosacea trees are dormant throughout the winter, it pays to learn about the diseases that can affect them once they mature in the spring and summer. Warm and humid Alberta weather conditions in the late spring and summer are ideal for tree growth, but unfortunately, they are also ideal for the growth of a bacterial disease of fruit trees known as fire blight (Erwina amylovora).

Fire blight affects primarily the rose family of trees and shrubs. Common members of this family include apple and crab apple, pear, mountain ash, cotoneaster, raspberry, flowering almond, and Saskatoon, all trees commonly found in urban yards. The bacteria can kill flowers, twigs and branches, and sometimes whole trees and shrubs. The following symptoms might indicate fire blight, and so if you spot any of them, it’s best to contact an expert here at Chipps Tree Care, as the disease is highly contagious, and if not properly treated can spread quickly.

• Leaves affected by Fire Blight are red and look fire-scorched, hence the name. Blighted leaves eventually brown and die but remain attached to the branch of the tree.

• If left untreated, Fire Blight affects new growth, with leaves exhibiting a dramatic downward wilting at the tips, resulting in a distinct “shepherd’s crook” on the ends of infected twigs.

• A clear, amber liquid may be found oozing from diseased twigs, which is highly charged with the bacterium, further causing the disease to spread. If even a small amount reaches healthy trees new infections can be generated.

• Some trees may develop secondary infections indicated by bark cankers, which appear as indented discoloured areas on the branches and trunks. These cankers are usually more serious infections that can lead to the eventual death of the tree.

• The fire blight bacteria can spread a number of ways, including transmission via insect, through the use of contaminated pruning tools, as well as strong winds and rain. Hailstorms help spread the disease by wounding the bark of healthy trees and making them vulnerable to infection.

If your tree is infected with fire blight, the first step to controlling the disease is to prune, remove and destroy all diseased wood. However, since pruning can also be a means of transmission it is critical that you not try this complex procedure yourself. Instead, contact us to schedule an appointment with an ISA-certified arborist. Our experts can be on-site the day you call, and have the knowledge and training to prune your tree following strict ISA cleaning and sanitization guidelines to prevent the disease from spreading.

Furthermore, our technicians can properly dispose of the infected branches, as diseased branches and other wood should be burned or buried in the landfill to prevent re-infection. For more information, contact our Chipps Tree Care specialists, who will be more than happy to help you with all your tree care, tree pruning, and tree removal and disposal needs.