Flyspeck prevention, Group A fungicides (strobilurins and Topsin M):  August-September spray dates

Background Information for this page
Return to Apple list for Easthampton MA
Weather data for Easthampton MA.  Forecast values begin September 24, 2017
      Continuous protection from roughly 14 days after Petal Fall (May 27) until 30 days before harvest preserves maximum lag between end of protection from the final fungicide application and potential for visible SBFS before harvest. 
      With continuous protection prior to the final fungicide spray, apples harvested by September 20 should be at low risk of visible sooty blotch and flyspeck (SBFS) if the Protection End Date from the final fungicide application is after August 15.  Apples harvested by October 10 (or by  October 31) should be at low risk if the Protection End Date is after September 3 (or September 12).
     These estimates are based on moderate infection pressure and climatic average temperature and rain/wetting hour accumulation.  Block history, local SBFS fungal density, tree size, cultivar, pruning, wind & sun exposure, air drainage, mowing and other site characteristics determine the actual risk of SBFS becoming visible before harvest.
Weather data for Easthampton MA.  Forecast values begin September 24, 2017
Inches Rain Spray Date
Estimates assume that fungicide was applied before rain on spray date
Protection End Date
for full-dose
Flint, Sovran, or
Topsin M
(deadline for postinfection strobilurin or Topsin M)
Date flyspeck infections could appear
(Left side = rough guess of flyspeck show date if weather beyond end of forecast range is in top 20% of years for both temperature and wet hours.  An "x" means there is no need for this scenario because show date is within forecast range.
    
Right side = rough guess of flyspeck show date for small, open canopy, low-risk trees.)
0 Tue, August 1 Aug. 5  (Aug 9) x September 9 (Sep. 26)
0.71 Wed, August 2 Aug. 5  (Aug 9) x September 9 (Sep. 26)
0 Thu, August 3 Aug. 15  (Aug 20) x September 21 (Oct. 16)
0.03 Fri, August 4 Aug. 15  (Aug 20) x September 21 (Oct. 16)
1.32 Sat, August 5 Aug. 15  (Aug 20) x September 21 (Oct. 16)
0 Sun, August 6 Aug. 27  (Sep 2) x September 30 (> Oct. 31)
0.10 Mon, August 7 Aug. 28  (Sep 3) x October 1  
0.05 Tue, August 8 Aug. 29  (Sep 3) x October 2  
0 Wed, August 9 Aug. 30  (Sep 5) (Oct. 4) October 4  
0 Thu, August 10 Aug. 31  (Sep 5) (Oct. 4) October 7  
0.03 Fri, August 11 Sep. 1  (Sep 5) (Oct. 4) October 7  
0.34 Sat, August 12 Sep. 2  (Sep 5) (Oct. 4) October 7  
0.09 Sun, August 13 Sep. 3  (Sep 6) (Oct. 5) October 10  
0 Mon, August 14 Sep. 3  (Sep 6) (Oct. 5) October 10  
0.17 Tue, August 15 Sep. 3  (Sep 6) (Oct. 5) October 10  
0 Wed, August 16 Sep. 5  (Sep 7) (Oct. 7) October 13  
0 Thu, August 17 Sep. 5  (Sep 7) (Oct. 7) October 13  
0.31 Fri, August 18 Sep. 5  (Sep 7) (Oct. 7) October 13  
0 Sat, August 19 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Sun, August 20 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Mon, August 21 Sep. 6  (Sep 12) (Oct. 8) October 19  
0.36 Tue, August 22 Sep. 6  (Sep 12) (Oct. 8) October 19  
0.21 Wed, August 23 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Thu, August 24 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Fri, August 25 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Sat, August 26 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Sun, August 27 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Mon, August 28 Sep. 6  (Sep 12) (Oct. 8) October 19  
0.02 Tue, August 29 Sep. 6  (Sep 12) (Oct. 8) October 19  
0.02 Wed, August 30 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Thu, August 31 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Fri, September 1 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Sat, September 2 Sep. 6  (Sep 12) (Oct. 8) October 19  
1.03 Sun, September 3 Sep. 6  (Sep 12) (Oct. 8) October 19  
0 Mon, September 4 Sep. 25   (Oct. 22) > Oct. 31  
0.11 Tue, September 5 Sep. 26 (Oct. 24)    
0.96 Wed, September 6 Sep. 27 (Oct. 26)    
0.47 Thu, September 7 Sep. 28 (Oct. 29)    
0 Fri, September 8 Sep. 29 (> Oct. 31)    
0 Sat, September 9 Sep. 30      
0 Sun, September 10 Oct. 1      
0 Mon, September 11 Oct. 2        
0 Tue, September 12 Oct. 3      
0 Wed, September 13 Oct. 4      
0.01 Thu, September 14 Oct. 5      
0 Fri, September 15 Oct. 6