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 May 31, 2018
      Continuous protection from roughly 14 days after Petal Fall (May 31) 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 19.  Apples harvested by October 10 (or by  October 31) should be at low risk if the Protection End Date is after August 30 (or September 5).
     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 May 31, 2018
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.)
Wed, August 1 Aug. 16  (Aug 20) (Sep. 1) September 15 (Oct. 12)
Thu, August 2 Aug. 17  (Aug 21) (Sep. 2) September 17 (Oct. 15)
Fri, August 3 Aug. 18  (Aug 22) (Sep. 3) September 18 (Oct. 18)
Sat, August 4 Aug. 19  (Aug 23) (Sep. 4) September 20 (Oct. 22)
Sun, August 5 Aug. 20  (Aug 24) (Sep. 5) September 21 (Oct. 26)
Mon, August 6 Aug. 21  (Aug 25) (Sep. 6) September 23 (> Oct. 31)
  Tue, August 7 Aug. 22  (Aug 26) (Sep. 7) September 25  
Wed, August 8 Aug. 23  (Aug 27) (Sep. 8) September 26  
Thu, August 9 Aug. 24  (Aug 28) (Sep. 10) September 28  
Fri, August 10 Aug. 25  (Aug 29) (Sep. 11) September 30  
Sat, August 11 Aug. 26  (Aug 30) (Sep. 12) October 2  
Sun, August 12 Aug. 27  (Aug 31) (Sep. 13) October 4  
Mon, August 13 Aug. 28  (Sep 1) (Sep. 14) October 6  
  Tue, August 14 Aug. 29  (Sep 2) (Sep. 15) October 9  
Wed, August 15 Aug. 30  (Sep 3) (Sep. 16) October 11  
Thu, August 16 Sep. 1  (Sep 5) (Sep. 19) October 17  
Fri, August 17 Sep. 2  (Sep 6) (Sep. 20) October 20  
Sat, August 18 Sep. 3  (Sep 7) (Sep. 21) October 23  
Sun, August 19 Sep. 4  (Sep 8) (Sep. 23) October 26  
Mon, August 20 Sep. 5 (Sep. 24) > Oct. 31  
  Tue, August 21 Sep. 6   (Sep. 25)    
Wed, August 22 Sep. 7 (Sep. 27)    
Thu, August 23 Sep. 8 (Sep. 28)    
Fri, August 24 Sep. 9 (Sep. 30)    
Sat, August 25 Sep. 10 (Oct. 1)    
Sun, August 26 Sep. 11 (Oct. 2)    
Mon, August 27 Sep. 12 (Oct. 4)    
  Tue, August 28 Sep. 13   (Oct. 5)    
Wed, August 29 Sep. 14 (Oct. 6)    
Thu, August 30 Sep. 15 (Oct. 8)    
Fri, August 31 Sep. 16 (Oct. 9)    
Sat, September 1 Sep. 17 (Oct. 11)    
Sun, September 2 Sep. 18 (Oct. 12)    
Mon, September 3 Sep. 19 (Oct. 14)    
  Tue, September 4 Sep. 20   (Oct. 16)    
Wed, September 5 Sep. 21 (Oct. 17)    
Thu, September 6 Sep. 22 (Oct. 19)    
Fri, September 7 Sep. 23 (Oct. 21)    
Sat, September 8 Sep. 24 (Oct. 23)    
Sun, September 9 Sep. 25 (Oct. 25)    
Mon, September 10 Sep. 26 (Oct. 27)    
  Tue, September 11 Sep. 27   (Oct. 29)    
Wed, September 12 Sep. 28 (> Oct. 31)    
Thu, September 13 Sep. 29      
Fri, September 14 Sep. 30      
Sat, September 15 Oct. 1