Dan Donahue and colleagues with Cornell Coorperative Extension in in eastern New York State began studying the Honeycrisp bitter pit issue in 2016. Their objectives were very practical, looking to identify producer practices that would significantly reduce Bitter pit incidence, and also develop a method of bitter pit (BP) incidence prediction in stored apples that was reasonable economical and accurate. They are evaluating early season PGR and foliar calcium strategies, as well as conducting a 36-site survey study. To date, they have learned that Prohexadione-Calcium (ApogeeR, BASF) applied at pink can suppress BP 50%, Prohexadione-Calcium applied later for vegetative growth management as commonly practiced can aggravate bitter pit, at least one formulation of foliar calcium, POMA (6% calcium chelate), can suppress bitter pit when applied during the cell mitosis phase of fruit development. For 2019, Dan is leading a statewide bitter pit prediction implementation project, evaluating the 2nd generation of his peel mineral model as well as the “passive” prediction protocol developed by Dr. Chris Watkins at Cornell.
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