How to Spot Dangerous Fire Blight on Your Trees

By: albertaarb - March 11, 2015

Some threats to your trees have intimidating names, even if they’re hard to spot. Fire Blight is certainly no exception. Fire flight is a devastating bacterial disease that affects people with the following types of trees or plants:

  1. Apple

  2. Pear

  3. Cotoneaster

  4. Hawthorn

  5. Saskatoon

  6. Members of the Rosaceae (or rose) family


It’s a fairly aggressive bacteria that can kill a mature tree in one or two years.

What Does Fire Blight Look Like


As the name would suggest, you’re looking for red. The leaves will take on a red and somewhat scorched looking appearance. You will also see some orange coloured seepage out of the diseased leaves.

If you think your tree may be infected, please call a professional arborist or tree expert to give it a look over. Also look for an Infected blossom to suddenly wilt and turn light to dark brown.

According to, “Cankers begin to develop and are discoloured, slightly sunken and tend to crack at the edges. Cankers may eventually encircle the branch causing death.”

What are My Options?


According to the City of Calgary, your first step is to prune the effected branches.

“However, since pruning can also be a means of transmission it is critical that the correct procedure is followed, to ensure that no diseased wood is left and no healthy wood is accidentally infected. In the summer, all pruning cuts should be made a minimum of 30 cm (10 inches) into healthy wood.”

They added, ”The bacteria are less infective during the winter, and therefore pruning cuts only need to be 15 cm from points of infection.”

How Dangerous is Fire Blight?


The effects can be devastating. Last summer, fire blight scorched up to 80 per cent of some apple orchards in the Annapolis Valley in Nova Scotia.

"Fire blight has certainly reached an epidemic level this year and it's affected probably about ¾ to 80 per cent of the orchards here in the Valley," said Perennia Horticulturalist Chris Duyvelshoff.

More Than Pruning


Even after you remove the problem from your trees, the bacteria may remain on your equipment. The City stated, “After each and every pruning cut, the cutting blade must be sanitised with a solution of household bleach and water at a concentration of one part bleach to nine parts water.”

“This sanitising treatment will kill bacteria, but may also cause the cutting blade to discolour and corrode.”

Consult the Professionals


If you’re unsure of how to spot or remove any diseases, like fire blight, please call a professional.

At Alberta Arborists, we have helped countless people get rid of trees safely and efficiently, and we can help you, too. Our highly experienced arborists are trained to deal with any tree removal in any location and to ensure no damage is done to your property.


Contact us today for a free, no-obligation estimate of your job, and save your money, time (and body) from taking care of the tree removal yourself

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