Monday, October 19, 2015

As you’re collecting your leaves this fall, watch out for bronze leaf disease

Do you have poplar or aspen trees in your yard? When you are picking up your leaves, be on the lookout for bronze leaf disease.

What to look for

Symptoms of bronze leaf disease typically appear in late summer or early fall and may only be on a few branches or leaves.

  • Symptoms may spread around the tree and dieback may occur on infected branches.
  • Infected leaves turn orange-brown to reddish-brown and typically colouration starts at the edges of the leaf and moves inward toward the base.
  • The colour of infected leaves varies from very bronze to chocolate brown to dull brown.
  • A defining characteristic of the disease is the way that the leaf veins often remain a bright green in stark contrast to the rest of the leaf.
How to stop it

Good sanitation is the best method of controlling the disease.
  • Pick up leaf litter from under the trees as soon as they drop.
  • Prune out affected branches 20-30 cm (8-12 in.) into healthy wood while still attempting to maintain the tree's shape. Often, this is back to the trunk. Removal of dead and or dying trees is important as they will infect nearby trees as well.
  • Fallen leaves and pruned wood should be bagged and disposed of in the garbage only.
  • Do not compost or burn any infected wood or leaves.
  • Do not bring infected leaves and wood to Leaf and Pumpkin Composting drop-off locations. Instead, dispose of it in the garbage or take directly to the landfill.
  • If you are unsure about how/where to prune, we recommend hiring an International Society of Arboriculture-certified arborist.
  • Equipment used to prune trees should be sanitized between cuts to avoid transferring the disease.
  • If you suspect bronze leaf disease in a City-owned tree, contact 311.
As with all tree diseases, the best defence is a healthy tree. Visit for healthy tree care tips.


  1. Replies
    1. Hi there. The Community Standards Bylaw prohibits the burning of leaves, brush or yard waste in a fire pit within city limits. You can find further info on fire pit regulations here: