Flyspeck prevention with Group A fungicides (strobilurins and Topsin M): July spray dates

Background Information for this page
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      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 July 16, 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 Sun, July 1 July 22  (Jul 24) (Aug. 6) August 15 (Aug. 29)
0 Mon, July 2 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Tue, July 3 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Wed, July 4 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Thu, July 5 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0.20 Fri, July 6 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Sat, July 7 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Sun, July 8 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Mon, July 9 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Tue, July 10 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Wed, July 11 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Thu, July 12 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Fri, July 13 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Sat, July 14 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0.22 Sun, July 15 July 23  (Jul 24) (Aug. 7) August 17 (Sep. 1)
0 Mon, July 16 July 24  (Jul 26) (Aug. 9) August 19 (Sep. 3)
1.13 Tue, July 17 July 24  (Jul 26) (Aug. 9) August 19 (Sep. 3)
0.03 Wed, July 18 July 31  (Aug 4) (Aug. 16) August 27 (Sep. 13)
0 Thu, July 19 July 31  (Aug 4) (Aug. 16) August 27 (Sep. 13)
0 Fri, July 20 July 31  (Aug 4) (Aug. 16) August 27 (Sep. 13)
0 Sat, July 21 July 31  (Aug 4) (Aug. 16) August 27 (Sep. 13)
0.29 Sun, July 22 July 31  (Aug 4) (Aug. 16) August 27 (Sep. 13)
0.48 Mon, July 23 August 2  (Aug 6) (Aug. 18) August 29 (Sep. 16)
0.32 Tue, July 24 August 6  (Aug 10) (Aug. 22) September 3 (Sep. 21)
0.25 Wed, July 25 August 9  (Aug 13) (Aug. 25) September 6 (Sep. 26)
Thu, July 26 August 11  (Aug 15) (Aug. 27) September 9 (Sep. 30)
Fri, July 27 August 12  (Aug 16) (Aug. 28) September 10 (Oct. 2)
  Sat, July 28 August 13  (Aug 17) (Aug. 29) September 11 (Oct. 4)
Sun, July 29 August 14  (Aug 18) (Aug. 30) September 12 (Oct. 7)
Mon, July 30 August 15  (Aug 19) (Aug. 31) September 14 (Oct. 9)
Tue, July 31 August 16  (Aug 20) (Sep. 1) September 15 (Oct. 12)