SW MICHIGAN APPLE MATURITY REPORT

ISSUE 2 – Sept 11, 2007

 

Summaries of apple maturity for SW Michigan begin this week and continuing through mid October. The samples for these reports are collected in Berrien County—the maturity is only a broad indication of trends for this area. Contact Bill Shane at SWMREC 269-944-1477 x 205 if you would like to have samples from your farm tested for maturity.   

 

Jonathan (7 sites sampled, 2nd week) Fruit firmness averaged 17.7 lb (range 16.2 to 20) still in the excellent zone of 21 to 16 lb, but noticeably softer than last week.  Starch removal average of 4.0, compared to last weeks 3.3 with most sites in the mature zone.  Brix is averaging 13.2, about the same as last week.  Growers are actively harvesting of Jonathans destined for processing.  Jonathans similar to those samples can be stored successfully for long term CA storage, although skin color still may be too green for some fresh markets.

                             CA longterm firmness      Firmness          ----    Starch removal   -----------

Guidelines:          Excellent  Acceptable        short term       immature      mature        overmature

Jonathan               > 16 lb       16 to 15 lb           < 15              < 3.5        3.5 to 5.5      > 5.5

 

Empire (4 samples, 3rd week of samples) firmness averaged 18.0 lb, about the same as last week (range 23 to 14 lb.   Starch removal averaged 3.2 compared to 2.5 for last week.  Brix average 11.9 compared to 11.5 degrees for last week. Blush of Empires have been improving and is very good in blocks with lower vigor and good fruit exposure. This will be the last sample date for Empires as most have been harvested.  Based on these tests, harvest can be delayed for Empire apples destined for CA storage or for local sales to wait for better starch conversion to sugar.

                             CA longterm firmness      Firmness          ----    Starch removal   -----------

Guidelines:          Excellent  Acceptable        short term       immature      mature        overmature

Empire (export)      > 18 lb       18 to 17 lb           < 15              < 3.5        3.5 to 5.5      > 5.5

          (domestic)     > 16 lb       16 to 15 lb          <  15              < 3.5       3.5  to 5.5     > 5.5

           

Honeycrisp (no official test samples) are being harvested this week with many orchards finished this week. Bitter pit is becoming more evident on sandy sites.  Rot in skin cracks is common. 

 

Jonagold (3 sample sites, 2nd week) are testing 18.3 compared to 19 lb for last week.  Starch removal index readings average 3.7 compared to 2.3 for last week.  Average brix this week is 13, about the same as last weeks 13.2.   Good firmness will allow delay of harvest to wait for better background color if needed for some sites, however pressure tests for a few sites less than 17 lb and starch removal in the mature for most indicates that harvest of most sites should be underway if color permits. 

                             CA longterm firmness      Firmness          ----    Starch removal   -----------

Guidelines:          Excellent  Acceptable        short term       immature      mature        overmature

Jonagold                > 16 lb       16 to 15 lb           < 15              < 3.5        3.5 to 5.5      > 5.5

 

Golden Delicious  (8 samples, 2nd week).  Firmness this week averages 18.4 compared to 18.8 lb for last week.  The starch index for this week averaged 2.0 compared to last weeks 1.3—still in the immature range.  Brix averaged 13.0, about the same as last week.  Pink blush is becoming more obvious.  Fruit finish is very nice this year in general aside from some sites with frost marks and some sunscald due to hot conditions earlier in the season..

                             CA longterm firmness      Firmness          ----    Starch removal   -----------

Guidelines:          Excellent  Acceptable        short term       immature      mature        overmature

G. Delicious        > 17 lb       17 to 16 lb           < 15              < 3.0        3.0 to 5.0          > 5.0

 

Red Delicious (4 samples, 1st week, note: early strains such as Earlichief not included in this sample).  Firmness averaged 17.7 lb, with starch index of 2.9 and brix of 10.1.  All samples tested are already below the 18 lb level for excellent firmness and have starch conversion in the mature zone.  Harvest can proceed for orchards with sufficient skin color.  This variety is relatively advanced this year.

                            CA longterm firmness      Firmness          ----    Starch removal   -----------

Guidelines:          Excellent  Acceptable        mid term       immature      mature        overmature

Red Delicious        > 18 lb       18 to 17 lb      17 to 16 lb     < 2.5        2.5 to 5.0          > 5.0

 

Current and past years summaries can be found on the SW Michigan Research and Extension Center web site:    www.maes.msu.edu/swmrec.  At this site click on publications and then fruit reports.   Reports for all the apple producing regions of Michigan can be found by going to the following web site:    web1.msue.msu.edu/fruit/ripeapple.htm.


This report and project is made possible by the support of our sponsors which include Gerber Products Company, Valent USA, Michigan Apple Research Committee, Michigan State Horticultural Society, Michigan Agricultural Experiment Station, and Michigan State University Extension.  SW growers providing apples include Grandview Orchards, Mammoth Farms, Oak Hill, Bixby Orchards, Willmeng Farms, and Czuba Farms.