McIntosh Budstage forecast
- Background

     Bud stage forecasts are based on degree day values identified by:

Dave P. Kain, NY State Agric. Exp. Sta., Cornell University; 
Phillip G. Schwallier, Michigan State University Coop. Ext.;
and G. DeBruin, Reister's Grower Services, MI. 

     Having an early season biofix corrects for latitudinal shift in correlation between pest lifestage and cumulative degree days (DD).  Experience with DD values for Geneva NY apple pest observations found that early season events in Maine occur at a lower DD accumulation.  But experience has also found that DD - observable event correlations are accurate when the DD value reset with an early season calibration starting point such as McIntosh Green tip. 

     Doing this eliminates the error that accumulates prior to Green tip, and from that point on, DD correlations developed at Geneva New York work for New England.

      The definitions of the apple bud stage dates are all for McIntosh on typical rootstocks (M7, M26 etc.)

Green Tip = date when 50% of McIntosh fruit buds showing 1-2 mm green tissue exposed when viewed from the side

Half-inch Green =  date when 50% of McIntosh fruit buds show half inch of green tissue, two little "mouse ear" leaves folding back.

King Bloom = date when most McIntosh trees in the block show first open blossom.

95% Petal Fall = date when most McIntosh trees have only 5% of the blooms still on the tree, the others having already fallen.  (this can be several days before final blossoms fall).

New York tree fruit bud stage photos for apple, pear, peach, plum & prune, tart cherry, and sweet cherry.  http://www.nysaes.cornell.edu/pubs/fls/OCRPDF/58a.pdf

Michigan Apple Bud stage definition photos
http://web1.msue.msu.edu/fruit/applgrw.htm

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Thanks to our Biofix reporters:

ME - Glen Koehler, Greg Koller, Ellen McAdam, Evan McDougal, Renae Moran
NY - Dave Kain
RI - Heather Faubert