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 December 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 26.  Apples harvested by October 10 (or by  October 31) should be at low risk if the Protection End Date is after September 17 (or September 25).
     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 December 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.)
0.74 Wed, August 1 Aug. 4  (Aug 7) x August 26 (Sep. 11)
0.47 Thu, August 2 Aug. 4  (Aug 7) x August 26 (Sep. 11)
0.75 Fri, August 3 Aug. 7  (Aug 10) x September 1 (Sep. 12)
1.21 Sat, August 4 Aug. 8  (Aug 11) x September 4 (Sep. 13)
0 Sun, August 5 Aug. 11  (Aug 12) x September 7 (Sep. 16)
0 Mon, August 6 Aug. 11  (Aug 12) x September 7 (Sep. 16)
0.79 Tue, August 7 Aug. 11  (Aug 12) x September 7 (Sep. 16)
0.60 Wed, August 8 Aug. 12  (Aug 13) x September 9 (Sep. 17)
0.15 Thu, August 9 Aug. 13  (Aug 16) x September 10 (Sep. 21)
0.05 Fri, August 10 Aug. 13  (Aug 16) x September 10 (Sep. 21)
1.14 Sat, August 11 Aug. 13  (Aug 16) x September 10 (Sep. 21)
0.30 Sun, August 12 Aug. 14  (Aug 17) x September 11 (Sep. 24)
0.58 Mon, August 13 Aug. 17  (Aug 20) x September 13 (Sep. 26)
1.16 Tue, August 14 Aug. 17  (Aug 20) x September 13 (Sep. 26)
0 Wed, August 15 Aug. 22  (Aug 27) x September 17 (Oct. 1)
0 Thu, August 16 Aug. 22  (Aug 27) x September 17 (Oct. 1)
1.13 Fri, August 17 Aug. 22  (Aug 27) x September 17 (Oct. 1)
0.71 Sat, August 18 Sep. 8  (Sep 11) x September 29 (Oct. 9)
0.01 Sun, August 19 Sep. 9  (Sep 11) x September 29 (Oct. 9)
0 Mon, August 20 Sep. 10  (Sep 11) x September 30 (Oct. 10)
0 Tue, August 21 Sep. 10  (Sep 11) x September 30 (Oct. 10)
0.50 Wed, August 22 Sep. 10  (Sep 11) x September 30 (Oct. 10)
0.01 Thu, August 23 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Fri, August 24 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Sat, August 25 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Sun, August 26 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Mon, August 27 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Tue, August 28 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Wed, August 29 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Thu, August 30 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Fri, August 31 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Sat, September 1 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Sun, September 2 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Mon, September 3 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Tue, September 4 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0 Wed, September 5 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0.51 Thu, September 6 Sep. 11  (Sep 12) x October 1 (Oct. 12)
0.03 Fri, September 7 Sep. 12  (Sep 13) x October 4 (> Oct. 31)
0 Sat, September 8 Sep. 12  (Sep 13) x October 4  
0 Sun, September 9 Sep. 12  (Sep 13) x October 4  
1.32 Mon, September 10 Sep. 12  (Sep 13) x October 4  
0.28 Tue, September 11 Sep. 18  (Sep 24) x October 11  
0.86 Wed, September 12 Sep. 18  (Sep 24) x October 11  
0.29 Thu, September 13 Sep. 18  (Sep 24) x October 11  
0 Fri, September 14 Sep. 18  (Sep 24) x October 11  
0 Sat, September 15 Sep. 18  (Sep 24) x October 11