Image of developing pear fruitlet infected with fire blight
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Ontario Fire Blight Prediction Maps Now Available

Fire blight decision management tool now available for apple and pear growers

The fire blight prediction maps for apple and pear are now available for the 2019 season at the following links:


These maps are based on the Cougar Blight model to help support apple and pear growers with their fire blight management decisions. The risk is based on the 7-day weather forecasts from 67 locations throughout the province.

The maps are animated and will cycle through the daily fire blight risk predictions based on the 7-day weather forecast. Updated maps will be generated and posted three times per week (Monday, Wednesday and Friday) until bloom period is over. Users can zoom in and out of the maps, reposition them to their specific locations and pause or start the maps.

The risk assumes that open blossoms are present and dew or rain will wet the blossom which is necessary for a fire blight infection to occur. If there are no open blossoms or if wetting of the open blossoms does not occurs, infection will most likely not take place. However, it only takes a little dew to wash the fire blight bacteria into the open blossom.

As with any model, the fire blight risk maps are a general guide. Environmental conditions may be more conducive for fire blight infection in a particular orchard than what is indicated by the maps. All apple and pear growers are encouraged to run either the Cougar Blight or Maryblyt model with data generated from their orchards for a more accurate prediction.

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