East Michigan apple maturity report – Sept. 5, 2018

Some early maturing Gala and Honeycrisp blocks are ready to begin a first light harvest.

September 5, 2018 - Author:

General apple harvest comments

This Monday, Sept. 3, was the first week to collect apple samples from a number of orchards in east Michigan and to have them analyzed at the Department of Horticulture Post Harvest Lab at Michigan State University. This week I collected samples of Gala, McIntosh and Honeycrisp. Based on only one week’s worth of data, some early maturing strains and sites of Gala and Honeycrisp are ready for a light early harvest. McIntosh are not ready for harvest. More details on each of these varieties follow.

So far this season it appears there is a wide spread of maturity of individual apples on the tree. This may change once we get in to harvest further. Fruit size is generally on the smaller side this season, except on farms that have irrigating on a regular basis this summer or the few fortunate growers that have received timely precipitation. Fruit color is generally poor at this time, mainly due to the heat of the last several weeks.

Our bloom period this spring was early and extended for three weeks. Further, our growing season has had record heat and has been running 10 to 14 days ahead of normal for most of the summer. The 2018 predicted harvest dates that were published this summer partially reflect these factors. However, based on today’s data for the maturity of Gala, McIntosh and Honeycrisp, our harvest windows are tending to run a few days even earlier than the predicted harvest days. Spend time in your orchard soon to evaluate the maturity of your apple varieties.

Apple maturity in east Michigan for apples harvested Sept. 3

Variety

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Gala

45 (0-90)

78 (56-93)

17.6 (15.4-19.4)

3.1(1.2-5.7)

12.4

McIntosh

5 (0-10)

52(36-69)

15.6 (14.5-16.6)

2.5 (2.1-2.9)

12.3

Honeycrisp

80 (20-100)

60 (36-70)

15.4 (14.8-16.2)

4.8 (3.0-6.2)

12.8

Individual variety results

Gala was sampled for the first week of the season, with several strains being tested. The predicted harvest date for Gala for Deerfield is Sept. 5, or today, and for Romeo is Sept. 9. Based on this week’s data I think Gala is ready for harvest now for early maturing strains and sites. Fruit are still firm but only averaged 17.6 pounds pressure and an average starch index of 3.1. Dry conditions in many areas have slowed fruit sizing and color is poor to average. Do a block-by-block sampling to determine which are mature, and in most cases do a light spot picking to get the earliest maturing fruit off the tree.

Gala maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 3

45 (0-90)

78 (56-93)

17.6 (15.4-19.4)

3.1(1.2-5.7)

12.4

McIntosh was sampled for the first week of the season. Based on only one week of data, McIntosh are not ready to begin harvest. The predicted harvest date for McIntosh is Sept. 6. There has been some fruit drop in McIntosh, but most of the fruit has been pushed off the limb from growth rather than dropped on its own accord.

McIntosh maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 3

5 (0-10)

52(36-69)

15.6 (14.5-16.6)

2.5 (2.1-2.9)

12.3

Honeycrisp was sampled for the first week of the season. Recall that when I take a sample of any variety, we take the most mature fruit on the tree. So, in the case of Honeycrisp, this is the few fruits per tree that have a bright red color (what I call “stop light” color) with the background color changing to yellow.

The predicted harvest date for Honeycrisp is Sept. 12. Based on this week's data and eating a lot of them, the most mature stop light colored fruit on the tree are mature and ready for harvest. Here again, do a block-by-block sampling to determine which blocks are mature and do a very light first picking to get the earliest maturing 5 to 20 percent of the stop light colored fruit off the tree. Honeycrisp always require three to four pickings. The fruit that is ready is eating well.

Honeycrisp maturity for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 3

80 (20-100)

60 (36-70)

15.4 (14.8-16.2)

4.8 (3.0-6.2)

12.8

 

Suggested firmness and starch index levels for long-term and shorter-term controlled atmosphere (CA) storage by variety.

Variety

Firmness (pounds)*

Starch Index*

Short CA

Mid-CA

Long CA

Mature

Over mature

McIntosh

14

15

16

5

7

Gala

16

17

18

3

6

Honeycrisp

15

16

17

3.5

7

Empire

14

15

16

3.5

6

Early Fuji

16

17

18

3

7

Jonagold

15

16

17

3.5

5.5

Jonathan

14

15

16

3.5

5.5

Golden Delicious

15

16

17

3

6.5

Red Delicious

16

17

18

2.5

6

Idared

14

15

16

3.5

6

Fuji

16

17

18

3

7

Rome

15

16

18

3

5.5

*Firmness is measured with a mechanical 11-millimeter wide probe inserted into the pared flesh of a fruit to a distance of 8 millimeters. Starch index is measured on equatorial cross section of an apple stained with iodine solution and rated using the Cornell University starch-iodine index chart for apples on a 1-8 scale (Predicting Harvest Date Window for Apples by Blanpied and Silsbey, Cornell Extension Bulletin 221.)

Looking for more? View Michigan State University Extension’s Apple Maturity page for regional reports throughout the state and additional resources.

Tags: apple harvest 2018, apple maturity reports, east apple maturity report, msu extension


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