Protectant fungicide Respray Dates for Secondary Scab Suppression

Background Information for this page
Return to radar list for Middletown RI
       This table estimates fungicide intervals for suppressing spread of secondary scab if it should occur.  Use the appropriate primary scab respray guidelines instead of this table until ascospore releases are completed.  Rules used to estimate protection depletion change after fruit set and again after terminal bud set.  See Background Information page for details.
      Brown text with grey background indicates dates when 2nd generation scab lesions from the final ascospore release have had time to begin appearing.  After this date it is possible to confirm the status of primary scab control.  If successful control of primary apple scab infections has been confirmed, this table is no longer needed, and fungicide application dates can be made with the extended intervals adequate to prevent flyspeck and other summer diseases. 
      But if there are enough active scab infections present to cause an unacceptable risk of fruit scab infection, this table provides estimates for respray dates to keep scab infections from spreading.  If active lesions are found, fungicide protection is needed until those lesions exhaust their supply of spores, which takes about 4 weeks. 
       Depending on scab severity, market sensitivity, temperature, and proximity to harvest; shorter or longer fungicide intervals to suppress spread from active scab lesions may be more appropriate than the estimates shown below.
      The estimated date for 95+% scab ascsopore release at this site is May 19.   
The estimated McIntosh fruit set date for this site is May 27. 
The approximate terminal bud set date for this site is July 6.
Weather data for Middletown RI.  Forecast values begin October 14, 2011
Previous
Spray Date

Estimates assume that fungicide
was applied BEFORE rain
on spray date
Inches Rain Protection End Date against Secondary Scab
for full-dose
captan, mancozeb or other protectant fungicide
Percent primary scab potential beginning to show as
(1st generation)
&
2nd gen. lesions by protection end date
Respray Deadline
= Start date for next scab infection period after protection ends
Thu,  June  2 0 June 13, Mon (92%) 92% June 14, Tue
Fri,  June  3 0 June 13, Mon (92%) 92% June 14, Tue
Sat,  June  4 0 June 13, Mon (92%) 92% June 14, Tue
Sun,  June  5 0.02 June 13, Mon (92%) 92% June 14, Tue
Mon,  June  6 0 June 13, Mon (92%) 92% June 14, Tue
Tue,  June  7 0 June 13, Mon (92%) 92% June 14, Tue
Wed,  June  8 0.06 June 13, Mon (92%) 92% June 14, Tue
Thu,  June  9 0.51 June 13, Mon (92%) 92% June 14, Tue
Fri,  June  10 0 June 18, Sat (94%) 92% June 22, Wed
Sat,  June  11 0.68 June 18, Sat (94%) 92% June 22, Wed
Sun,  June  12 1.20 June 18, Sat (94%) 92% June 22, Wed
Mon,  June  13 0.05 June 24, Fri (100%) 92% June 25, Sat
Tue,  June  14 0.07 June 24, Fri (100%) 92% June 25, Sat
Wed,  June  15 0 June 24, Fri   92% June 25, Sat
Thu,  June  16 0 June 24, Fri 92% June 25, Sat
Fri,  June  17 0.90 June 24, Fri 92% June 25, Sat
Sat,  June  18 0.06 June 24, Fri 92% June 25, Sat
Sun,  June  19 0 June 26, Sun 92% June 29, Wed
Mon,  June  20 0 June 26, Sun 92% June 29, Wed
Tue,  June  21 0 June 26, Sun 92% June 29, Wed
Wed,  June  22 0.89 June 26, Sun   92% June 29, Wed
Thu,  June  23 1.10 July 7, Thu 100% July 8, Fri
Fri,  June  24 0.01 July 8, Fri July 12, Tue
Sat,  June  25 0.04 July 9, Sat July 12, Tue
Sun,  June  26 0 July 10, Sun July 12, Tue
Mon,  June  27 0 July 10, Sun July 12, Tue
Tue,  June  28 0 July 10, Sun July 12, Tue
Wed,  June  29 0.15 July 10, Sun     July 12, Tue
Thu,  June  30 0 July 10, Sun July 12, Tue
Fri,  July  1 0 July 10, Sun July 12, Tue
Sat,  July  2 0 July 10, Sun July 12, Tue
Sun,  July  3 0.03 July 10, Sun July 12, Tue
Mon,  July  4 0 July 10, Sun July 12, Tue
Tue,  July  5 0 July 10, Sun July 12, Tue
Wed,  July  6 0 July 10, Sun     July 12, Tue
Thu,  July  7 0 July 10, Sun July 12, Tue
Fri,  July  8 1.55 July 10, Sun July 12, Tue
Sat,  July  9 0.51 July 23, Sat July 23, Sat
Sun,  July  10 0 July 24, Sun July 24, Sun
Mon,  July  11 0 July 25, Mon July 25, Mon
Tue,  July  12 0.14 July 26, Tue July 26, Tue
Wed,  July  13 0.81 July 27, Wed     August 2, Tue
Thu,  July  14 0.36 July 28, Thu August 2, Tue
Fri,  July  15 0 July 29, Fri August 2, Tue
Sat,  July  16 0 July 30, Sat August 2, Tue
Sun,  July  17 0 July 31, Sun August 2, Tue
Mon,  July  18 0.08 August 1, Mon August 2, Tue
Tue,  July  19 0 August 2, Tue August 2, Tue
Wed,  July  20 0 August 3, Wed     August 6, Sat
Thu,  July  21 0 August 4, Thu August 6, Sat
Fri,  July  22 0 August 5, Fri August 6, Sat
Sat,  July  23 0.17 August 6, Sat August 6, Sat
Sun,  July  24 0.02 August 7, Sun August 8, Mon
Mon,  July  25 0.08 August 8, Mon August 8, Mon
Tue,  July  26 0.28 August 9, Tue August 9, Tue
Wed,  July  27 0 August 10, Wed     August 14, Sun
Thu,  July  28 0 August 10, Wed August 14, Sun
Fri,  July  29 0 August 10, Wed August 14, Sun
Sat,  July  30 0 August 10, Wed August 14, Sun
Sun,  July  31 0 August 10, Wed August 14, Sun
Mon,  August  1 0 August 10, Wed August 14, Sun
Tue,  August  2 0.17 August 10, Wed August 14, Sun
Wed,  August  3 0 August 11, Thu     August 14, Sun
Thu,  August  4 0 August 11, Thu August 14, Sun
Fri,  August  5 0 August 11, Thu August 14, Sun
Sat,  August  6 0.02 August 11, Thu August 14, Sun
Sun,  August  7 1.42 August 11, Thu August 14, Sun
Mon,  August  8 0.26 August 16, Tue August 21, Sun
Tue,  August  9 0.25 August 16, Tue August 21, Sun
Wed,  August  10 0.15 August 16, Tue     August 21, Sun
Thu,  August  11 0 August 16, Tue August 21, Sun
Fri,  August  12 0 August 16, Tue August 21, Sun
Sat,  August  13 0 August 16, Tue August 21, Sun
Sun,  August  14 0.05 August 16, Tue August 21, Sun
Mon,  August  15 2.43 August 16, Tue August 21, Sun
Tue,  August  16 0 August 29, Mon Too early to estimate
Wed,  August  17 0 August 29, Mon      
Thu,  August  18 0 August 29, Mon  
Fri,  August  19 0 August 29, Mon  
Sat,  August  20 0 August 29, Mon  
Sun,  August  21 0.11 August 29, Mon  
Mon,  August  22 0.29 August 29, Mon  
Tue,  August  23 0 August 29, Mon  
Wed,  August  24 0 August 29, Mon      
Thu,  August  25 0 August 29, Mon  
Fri,  August  26 0.03 August 29, Mon  
Sat,  August  27 0.56 August 29, Mon  
Sun,  August  28 1.52 September 7, Wed  
Mon,  August  29 0 September 9, Fri  
Tue,  August  30 0 September 9, Fri  
Wed,  August  31 0 September 9, Fri