Thank you for this, Glen - it is new information to me - I have been twiddling my thumbs waiting for color here, not only on Jonagold, but on all the later varieties - tonight will be the first night of the season in the lower 40’s/upper30’s - hope that we’ll see some color development soon - David Doud IN
> On Oct 13, 2016, at 12:10 AM, Glen Koehler <glen.koeh...@maine.edu> wrote: > > Hi Art > A contributing factor to problems with fruit color this fall has been > late arrival of minimum temperatures below 42F, A "rule of thumb" from a > Cornell bulletin is that optimum coloring conditions require two days with > low temperature below 42F, followed by a day with high temperature over 68F > AND over 80% sunlight on that day. > > The Ag-Radar estimate for Sanford 9 miles away from you (far enough that > I wish we had closer data site, working on that) shows that the two days > below 42F requirement was not met until September 26, and Sept. 27 had a high > temperature over 68F. But the requirement for a day with high temperature > over 68F AND over 80% sunshine was not met until October 6. > > I don't see this formula as a powerful predictor, esp. since I've seen > some good color improvement while checking traps and doing fall scab index > over the past few weeks. And even if it was a robust predictor, it wasn't > based on Jonagold. Still it gives some numbers to possibly help explain late > coloring conditions this fall. > > Easy to suspect the drought as a contributing factor. I'm also wondering > if you used ReTain on these Jonagold. If so, do you think that had any > effect on coloring? > > - Glen > > Glen Koehler > University of Maine Cooperative Extension > Pest Management Office > Voice: Office 207-581-3882, Cell 207-485-0918 > 491 College Avenue, Orono, ME 04473 > UMaine Apple IPM <https://extension.umaine.edu/ipm/programs/apple/> > Ag-Radar <https://extension.umaine.edu/ipm/ag-radar-apple-sites/> > On Wed, Oct 12, 2016 at 2:19 PM, kellyorchards <kellyorcha...@gmail.com > <mailto:kellyorcha...@gmail.com>> wrote: > Why are my Jonagolds not coloring? Can this be an issue if they have a heavy > crop? > > > > Art Kelly > Kelly Orchards > Acton, Maine > > _______________________________________________ > apple-crop mailing list > apple-crop@virtualorchard.com <mailto:apple-crop@virtualorchard.com> > http://virtualorchard.com/mailman/listinfo/apple-crop > <http://virtualorchard.com/mailman/listinfo/apple-crop> > > > _______________________________________________ > apple-crop mailing list > apple-crop@virtualorchard.com > http://virtualorchard.com/mailman/listinfo/apple-crop
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