Asiatic brown rot

Asiatic brown rot (Monilinia polystroma) is a fungal disease that affects stone fruits (for example, peach and plum) and pome fruits (for example, apples and pears). It causes blossom blight and brown fruit rot, which can lead to mummified fruit that remains on the tree or falls to the ground. The fungus can travel on infected plant material, such as nursery stock and fruit. Spores are spread over short distances by:

  • wind
  • rain splash
  • indirectly by insects and birds

Infection can spread from one fruit to another where they are in contact. It is not a risk to human or animal health.

Report an Asiatic brown rot sighting

Where it is

Asiatic brown rot is native to Asia, and it has been detected in multiple European countries:

  • Netherlands
  • Italy
  • Slovenia
  • Croatia
  • Hungary
  • Poland
  • Serbia
  • Russian Federation

It has been detected in the Montérégie region of Quebec but is not known to be found elsewhere in Canada.

How to spot it

The infection cycle of Asiatic brown rot has 3 main phases:

  • blossom and twig blight in early spring
  • brown rot of fruit in late summer and fall
  • mummified fruits on trees and soil during late fall to winter and early spring

Similar to other brown rot pests of stone fruit and apples, symptoms include:

  • brown and dying flowers on branches and blight or cankers on twigs
  • fruit that is covered in concentric rings of gray or cream-colored spores
  • small, water-soaked spots that rapidly enlarge into a soft, brown rot
  • shriveled and dry, mummified fruit
  • Figure 1: Infected twigs
    Figure 1: Infected twigs
  • Figure 2: apple covered in spores
    Figure 2: apple covered in spores
  • Figure 3: mummified fruit
    Figure 3: mummified fruit

What we are doing

Asiatic brown rot is a regulated pest in Canada. To help determine the distribution of Asiatic brown rot in Canada, we are conducting surveys in areas with host trees. When Asiatic brown rot is detected, official control measures may be put in place to prevent its spread.

We only permit fruits and fruit tree material to be imported from approved sources with CFIA-accepted certification measures in place to ensure plants and plant products enter Canada free of pests regulated by us, including Asiatic brown rot.

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