Fireblight infection conditions - Cougarblight model

Background Information for this page
Return to radar list for Monmouth ME
Weather data for Monmouth ME.  Forecast values begin September 20, 2011
     This table shows estimates of RELATIVE daily fireblight blossom infection risk based on weather conditions.  Rating criteria are from the Cougarblight 2010 model developed in Washington and Oregon by Dr. Timothy J. Smith.     
      ABSOLUTE risk depends on the amount of fire blight bacteria in the area, the number of open flowers, and cultivar and rootstock susceptibility.  Relative infection risk may be overstated for first few days of bloom because fire blight bacteria may not have been distributed to open flowers.   
      Gray shading indicates dates when most trees will have lost open blossoms, and are therefore no longer susceptible to blossom infection.  These dates included for later blooming cultivars and for late-blooming young trees.  Absolute risk is much lower on these dates than during full bloom, but apple trees with open blossoms on these dates are susceptible to the risk rating shown.  
      Fireblight infection can occur without rain if there is "heavy" dew.  But heavy dew is not defined in weather reports.  As a rough guess, if there is no rain on a day, but leaves are expected to be wet for at least 3 hours, then infection risk is reported with "if dew" attached.  Infection potential may be overstated on days when the "if dew" tag is attached.
     Fire blight risk categories vary by block history:
   I  = No active fire blight within 1 mile of the orchard this year or last year.  Requires 500 – 800 heat units for HIGH rating, 801 – 1000 for EXTREME!, and 1001+ for EXCEPTIONAL!
  
II = Fire blight was present within 1 mile of the orchard last year, but not currently active in the area this year.
Requires 200 – 350 heat units for HIGH rating, 351 – 500 for EXTREME!, and 501+ for EXCEPTIONAL!

  
III = Active fire blight cankers within 1 mile of the orchard this year. 
Requires 100 – 200 heat units for HIGH rating, 200 – 300 for EXTREME!, and 301+ for EXCEPTIONAL!
 If blossom infection occurred May 27, then blossom blight would be noticeable by June 9, and shoot blight by June 27.
Range of potential open blossom dates
for McIntosh and similar cultivars
Cougarblight Heat Units,
Inches Rain, & 
Leaf Wet Hours
I - No FB within
one mile last year
or this year
II - FB within one mile last year, but not active within one mile this year III - FB active within one mile of orchard this year.
Mac King Bloom
 Sat, May 21 
7 HU,  0.77'',  24 hrs Low Low Caution
Sun, May 22  8 HU,  0.08'',  13 hrs Low Low Caution
Mon, May 23  9 HU,  0.30'',  22 hrs Low Low Caution
Tue, May 24  45 HU,  0.0'',  16 hrs Low Low Caution
Wed, May 25  72 HU,  0.0'',  7 hrs Low Low Caution
Thu, May 26  91 HU,  0.18'',  11 hrs Low Low Caution
Fri, May 27  210 HU,  0.0'',  14 hrs Caution (if dew) HIGH (if dew) EXTREME! (if dew)
Sat, May 28  183 HU,  0.0'',  24 hrs Caution (if dew) Caution (if dew) HIGH (if dew)
Sun, May 29  234 HU,  0.32'',  14 hrs Caution HIGH EXTREME!
Mon, May 30  470 HU,  0.0'',  9 hrs Caution (if dew) EXTREME! (if dew) EXCEPTIONAL! (if dew)
Tue, May 31  422 HU,  0.0'',  0 hrs Low Low Low
Wed, June 1  482 HU,  0.44'',  15 hrs Caution EXTREME! EXCEPTIONAL!
Thu, June 2  404 HU,  0.0'',  5 hrs Caution (if dew) EXTREME! (if dew) EXCEPTIONAL! (if dew)
Fri, June 3  153 HU,  0.0'',  0 hrs Low Low Low
Sat, June 4  87 HU,  0.0'',  0 hrs Low Low Low
Sun, June 5  30 HU,  0.0'',  6 hrs Low Low Caution
Mon, June 6  84 HU,  0.0'',  4 hrs Low Low Caution
Tue, June 7  128 HU,  0.0'',  8 hrs Low Caution (if dew) HIGH (if dew)
Wed, June 8  314 HU,  0.0'',  10 hrs Caution (if dew) HIGH (if dew) EXCEPTIONAL! (if dew)
Thu, June 9  575 HU,  1.23'',  8 hrs HIGH EXCEPTIONAL! EXCEPTIONAL!
Fri, June 10  561 HU,  0.0'',  10 hrs HIGH (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Sat, June 11  516 HU,  0.38'',  10 hrs HIGH EXCEPTIONAL! EXCEPTIONAL!
Sun, June 12  325 HU,  0.35'',  24 hrs Caution HIGH EXCEPTIONAL!
Mon, June 13  57 HU,  0.02'',  18 hrs Low Low Caution
Tue, June 14  15 HU,  0.15'',  20 hrs Low Low Caution
Wed, June 15  58 HU,  0.0'',  9 hrs Low Low Caution
Thu, June 16  219 HU,  0.0'',  4 hrs Caution (if dew) HIGH (if dew) EXTREME! (if dew)
Fri, June 17  288 HU,  0.12'',  16 hrs Caution HIGH EXTREME!
Sat, June 18  326 HU,  0.42'',  21 hrs Caution HIGH EXCEPTIONAL!
Sun, June 19  314 HU,  0.0'',  8 hrs Caution (if dew) HIGH (if dew) EXCEPTIONAL! (if dew)
Mon, June 20  226 HU,  0.0'',  0 hrs Low Low Low
Tue, June 21  301 HU,  0.0'',  0 hrs Low Low Low
Wed, June 22  310 HU,  0.29'',  4 hrs Caution HIGH EXCEPTIONAL!
Thu, June 23  283 HU,  0.46'',  24 hrs Caution HIGH EXTREME!
Fri, June 24  211 HU,  0.95'',  24 hrs Caution HIGH EXTREME!
Sat, June 25  69 HU,  0.33'',  24 hrs Low Low Caution
Sun, June 26  44 HU,  0.09'',  22 hrs Low Low Caution
Mon, June 27  223 HU,  0.0'',  10 hrs Caution (if dew) HIGH (if dew) EXTREME! (if dew)
Tue, June 28  323 HU,  0.0'',  8 hrs Caution (if dew) HIGH (if dew) EXCEPTIONAL! (if dew)
Wed, June 29  356 HU,  0.04'',  19 hrs Caution EXTREME! EXCEPTIONAL!
Thu, June 30  367 HU,  0.0'',  9 hrs Caution (if dew) EXTREME! (if dew) EXCEPTIONAL! (if dew)
Fri, July 1  235 HU,  0.13'',  16 hrs Caution HIGH EXTREME!
Sat, July 2  234 HU,  0.0'',  10 hrs Caution (if dew) HIGH (if dew) EXTREME! (if dew)
Sun, July 3  228 HU,  0.60'',  23 hrs Caution HIGH EXTREME!
Mon, July 4  349 HU,  0.01'',  15 hrs Caution HIGH EXCEPTIONAL!
Tue, July 5  655 HU,  0.0'',  10 hrs HIGH (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Wed, July 6  854 HU,  0.55'',  13 hrs EXTREME! EXCEPTIONAL! EXCEPTIONAL!
Thu, July 7  990 HU,  0.0'',  11 hrs EXTREME! (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Fri, July 8  888 HU,  0.25'',  2 hrs EXTREME! EXCEPTIONAL! EXCEPTIONAL!
Sat, July 9  634 HU,  0.0'',  11 hrs HIGH (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Sun, July 10  559 HU,  0.0'',  0 hrs Low Low Low
Mon, July 11  844 HU,  0.53'',  0 hrs EXTREME! EXCEPTIONAL! EXCEPTIONAL!
Tue, July 12  1206 HU,  0.0'',  12 hrs EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Wed, July 13  1238 HU,  0.33'',  10 hrs EXCEPTIONAL! EXCEPTIONAL! EXCEPTIONAL!
Thu, July 14  1067 HU,  0.0'',  8 hrs EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Fri, July 15  786 HU,  0.0'',  7 hrs HIGH (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Sat, July 16  722 HU,  0.0'',  0 hrs Low Low Low
Sun, July 17  1143 HU,  0.0'',  0 hrs Low Low Low
Mon, July 18  1346 HU,  0.0'',  0 hrs Low Low Low
Tue, July 19  1514 HU,  0.0'',  9 hrs EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew) EXCEPTIONAL! (if dew)
Wed, July 20  1515 HU,  0.0'',  0 hrs Low Low Low
Thu, July 21  1781 HU,  0.0'',  0 hrs Low Low Low
Fri, July 22  2223 HU,  0.0'',  0 hrs Low Low Low