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 August 3, 2008
     Weather-based RELATIVE daily fireblight blossom infection risk values below are according to criteria of the Cougarblight model developed in Washington state by Dr. Timothy J. Smith.     
      ABSOLUTE risk also depends on cultivar and rootstock susceptibility, and on the number of flowers open. Infection risk may be overstated for first few days of bloom because fire blight bacteria may not have been distributed to open flowers.
      Cougarblight heat units are similar to degree hours base 60 F.
   
NOTICE! - Fireblight infection can occur without rain if there is "heavy" dew.  But "heavy" dew in relation to fireblight is not defined.  As a rough guess, if there is no rain on a day, but leaf wetness is expected to exceed 3 hours for that day, then infection conditions are reported with "if dew" attached.  Infection potential may be overstated on days when the "if dew" tag is attached.
Range of
potential
open-blossom dates
Gray box indicates dates when most trees will have lost open blossoms and susceptibility to blossom infection.  Gray box dates included for late cultivars and late-blooming young trees.
Fire blight risk categories by block history
 I  = No FB in the area during last two seasons
      requires 500+ heat units for HIGH! rating, 800+ for EXTREME!

 
II = FB present in the area, but not within 1 mile of your orchard last
    year requires 400+ heat units for HIGH! rating, 650+ for EXTREME!

 
III = FB in this orchard block or neighboring orchard last year
      requires 300+ heat units for HIGH! rating, 500+ for EXTREME!

 
IV = Active FB strikes or cankers present in this or neighboring block
      requires 200+ heat units for HIGH! rating, 350+ for EXTREME!
   If fire blight blossom infection occurred on May 27, then blossom blight would be noticeable by June 11, and shoot blight by June 25.
Inches Rain &
Leaf Wet Hours &
Heat Units
No FB in area for last two years
I
FB in area
last year,
but over 1 mile away
II
FB last year within 1 mile
III
Currently active FB
IV
Fri, May 16    0.'',  0 hrs.,  15 HU 0 0 0 0
Sat, May 17    0.03'',  6 hrs.,  26 HU Low Low Low Low
Sun, May 18    0.'',  0 hrs.,  46 HU 0 0 0 0
Mon, May 19    0.06'',  8 hrs.,  46 HU Low Low Low Low
Tue, May 20    0.'',  0 hrs.,  31 HU 0 0 0 0
Wed, May 21    0.13'',  11 hrs.,  20 HU Low Low Low Low
Thu, May 22    0.05'',  15 hrs.,  0 HU Low Low Low Low
Fri, May 23    0.09'',  19 hrs.,  0 HU Low Low Low Low
Sat, May 24    0.'',  8 hrs.,  2 HU Low Low Low Low
Sun, May 25    0.'',  0 hrs.,  67 HU 0 0 0 0
Mon, May 26    0.02'',  1 hrs.,  162 HU Low Low Marginal Marginal
Tue, May 27    0.05'',  5 hrs.,  286 HU Low Low Marginal HIGH!
Wed, May 28    0.'',  0 hrs.,  288 HU 0 0 0 0
Thu, May 29    0.'',  0 hrs.,  289 HU 0 0 0 0
Fri, May 30    0.'',  0 hrs.,  211 HU 0 0 0 0
Sat, May 31    0.82'',  22 hrs.,  87 HU Low Low Low Low
Sun, June 1    0.'',  13 hrs.,  180 HU Low Low Marginal
(if dew)
Marginal
(if dew)
Mon, June 2    0.02'',  7 hrs.,  161 HU Low Low Marginal Marginal
Tue, June 3    0.2'',  12 hrs.,  214 HU Low Low Marginal HIGH!
Wed, June 4    0.3'',  24 hrs.,  214 HU Low Low Marginal HIGH!
Thu, June 5    0.05'',  19 hrs.,  140 HU Low Low Low Marginal
Fri, June 6    0.19'',  24 hrs.,  92 HU Low Low Low Low
Sat, June 7    0.'',  14 hrs.,  174 HU Low Low Marginal
(if dew)
Marginal
(if dew)
Sun, June 8    0.'',  0 hrs.,  553 HU 0 0 0 0
Mon, June 9    0.'',  0 hrs.,  925 HU 0 0 0 0
Tue, June 10    0.65'',  17 hrs.,  1217 HU EXTREME! EXTREME! EXTREME! EXTREME!
Wed, June 11    0.28'',  11 hrs.,  1275 HU EXTREME! EXTREME! EXTREME! EXTREME!
Thu, June 12    0.'',  0 hrs.,  990 HU 0 0 0 0
Fri, June 13    0.'',  0 hrs.,  793 HU 0 0 0 0
Sat, June 14    0.'',  0 hrs.,  637 HU 0 0 0 0
Sun, June 15    0.51'',  24 hrs.,  426 HU Marginal HIGH! HIGH! EXTREME!
Mon, June 16    0.4'',  24 hrs.,  331 HU Low Low HIGH! HIGH!
Tue, June 17    0.24'',  16 hrs.,  159 HU Low Low Marginal Marginal
Wed, June 18    0.22'',  14 hrs.,  57 HU Low Low Low Low
Thu, June 19    0.01'',  15 hrs.,  89 HU Low Low Low Low
Fri, June 20    0.24'',  22 hrs.,  121 HU Low Low Low Marginal
Sat, June 21    0.'',  12 hrs.,  189 HU Low Low Marginal
(if dew)
Marginal
(if dew)
Sun, June 22    0.7'',  21 hrs.,  227 HU Low Low Marginal HIGH!
Mon, June 23    0.12'',  24 hrs.,  266 HU Low Low Marginal HIGH!
Tue, June 24    0.15'',  19 hrs.,  355 HU Low Marginal HIGH! EXTREME!
Wed, June 25    0.'',  8 hrs.,  443 HU Marginal
(if dew)
HIGH!
(if dew)
HIGH!
(if dew)
EXTREME!
(if dew)
Thu, June 26    0.02'',  1 hrs.,  574 HU HIGH! HIGH! EXTREME! EXTREME!