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Fire Blight - Cougarblight Risk Assessment Model
| Introduction | Using the Model | Additional Information | Archives |
Cougarblight Risk Predictions - 2006
(Models begin at first open blossom date for each area)
Location, County |
Albion,
Orleans Co. |
Chazy,
Clinton Co. |
Clifton Park,
Saratoga Co. |
Clintondale,
Ulster Co. |
Geneva,
Ontario Co. |
Ithaca,
Tompkins Co. |
Knowlesville,
Orleans Co. |
Lansing,
Tompkins Co. |
Lyndonville,
Niagara Co. |
Mexico,
Oswego Co. |
North Appleton,
Niagara Co. |
Sodus,
Wayne Co. |
Red Hook,
Dutchess Co. |
South Appleton,
Niagara Co. |
Waterport,
Orleans Co. |
Williamson,
Wayne Co. |
Introduction - Cougarblight is a risk assessment model for determining the risk of fire blight infection on flower blossoms. This model should be used from when your orchard enters bloom until only a few blossoms remain. The model calculates the sum of degree hours over the past four consecutive days to estimate the level of risk for fire blight infection. Additionally, the model modifies its predictions of risk based on the history of fire blight in, or around, your orchard the previous growing season.
Cougarblight was developed in the 1980's at Washington State University and has become the standard fire blight risk assessment model used in Oregon and Washington. Cougarblight could potentially function well in other commercial regions including the Northeast. An excellent description of how the model works is provided by Tim Smith, Washington State University Extension - http://www.ncw.wsu.edu/FB2000f.htm.
Using the Model - The following is a step-by-step description for determining the level of fire blight infection risk in your orchard.
Step 1 - It is first necessary to determine the 'Blight History' of your orchard.
'Blight History' |
Description of Fire Blight History |
1 |
No fire blight in the area for the past two years. |
2 |
Fire blight present in the region, but not in, or near, your orchard last year. |
3 |
Fire blight in, or near, your orchard last year. |
4 |
Fire blight strikes or cankers presently in, or near, your orchard. |
Step 2 - When your orchard enters bloom, look up the '4-day degree-hour sum' using the graphs for the location nearest to you (see table below or at the top of the page).
Location, County |
Albion,
Orleans Co. |
Geneva,
Ontario Co. |
Ithaca,
Tompkins Co. |
Knowlesville,
Orleans Co. |
Lansing,
Tompkins Co. |
Lyndonville,
Niagara Co. |
Mexico,
Oswego Co. |
North Appleton,
Niagara Co. |
Sodus,
Wayne Co. |
South Appleton,
Niagara Co. |
Waterport,
Orleans Co. |
Williamson,
Wayne Co. |
Step 3 - To determine your Cougarblight 'Risk Prediction Level', look up your 4-day degree hour sum relative to your 'Blight History' in the table below. This is also represented graphically for each location in the plots below the degree hour summary. Your risk is rated as either 'low', 'moderate' 'high', or 'extreme'.
'Blight History' |
4-day Degree-hour Sum |
Low (1) |
Moderate (2) |
High (3) |
Extreme (4) |
1 |
0-400 |
400-500 |
500-800 |
800+ |
2 |
0-350 |
350-400 |
400-650 |
650+ |
3 |
0-150 |
150-300 |
300-500 |
500+ |
4 |
0-100 |
100-200 |
200-350 |
350+ |
Step 4 - Finally, make a judgement on whether to take action based on the following guidelines:
Additional Information
Fire Blight Fact Sheet
Pest Management Guidelines for Commercial Tree-Fruit Production - Information on control practices and general apple production in New York.
Tree Fruit and Berry Pathology Pome Fruit Links!
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