Southwest Michigan apple maturity report – Oct. 16, 2019

Red Delicious and Ida Red harvests in the area are nearly done. Evercrisp, Rome, Fuji, Winesap and Braeburn will finish up the season.

General apple harvest comments

Light frosts at the beginning of this week were not severe enough to interfere with apple harvests. Generally, temperatures of 28 degrees Fahrenheit or lower are considered sufficient to cause fruit damage.

This will be our last 2019 apple maturity report for southwest Michigan. We are grateful to many people and organizations who make the Michigan State University Extension southwest Michigan area apple maturity program a success, either through direct funding or indirectly through cooperation. Other more northern areas will continue with reports for the next few weeks. See the end of this report for links.

Apple maturity in southwest Michigan for apples harvested Oct. 14, 2019

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Ida Red

16.2 (16.0-17.3)

3.0 (2.2-3.4)

11.7

Fuji (late season)

17.2 (16.0-18.0)

4.4 (3.0-6.2)

14.4

Rome

21.3 (21.0-22.0)

3.3 (3.0-4.0)

11.8

Braeburn

21.9 (19.2-24.0)

3.7 (2.2-5.0)

11.1

Evercrisp*

21.4

4.0

16.3

* Based on one site

Individual variety results

Ida Red

The current starch test average of 3.0 is still slightly below the mature threshold of 3.5. Minimum recommended firmness for long-term controlled atmosphere (CA) storage is 16 pounds, currently averaging 16.2. The predicted harvest date for Ida Red in central Berrien County is Oct. 15. Most IdaRed orchards in the area have been harvested.

Ida Red maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 23

18.0 (17.0-18.0)

1.7 (1.0-2.0)

10.5

Sept. 30

17.3 (16.2-20.0)

2.2 (2.0-3.0)

11.3

Oct. 7

16.4 (16.0-17.0)

2.4 (2.0-3.0)

11.6

Oct. 14

16.2 (16.0-17.3)

3.0 (2.2-3.4)

11.7

Fuji (late season varieties)

The current firmness is testing at 17.2, about 0.5 pound less than last week and above 16 pounds, the recommended minimum firmness for long-term CA storage. The recommended minimum starch reading for maturity is 3.0, the current reading is 4.4. Based on the firmness, harvest can be delayed to wait for better size, brix and skin color, but not too long. Watercore symptoms are showing up in the flesh in some samples.

The predicted harvest date for Fuji for central Berrien County is Oct. 28, but the fruit are maturing earlier than that. Most Fuji in the area have not been harvested yet.

My colleague Amy Irish-Brown says that in years past when sugar levels are high as they seem to be this year, Fuji (and other varieties) can get callus tissue inside the core. This often is mistaken by buyers for moldy core. Buyers have tried to reject loads for this non-defect. Check out the article “Moldy Core of Apple” from Kari Peters at Penn State University Extension for a good comparison of moldy core and callus tissue with pictures to help with the identification.

Fuji (main season) maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 23

20.5 (19.4-22.0)

3.2 (2.4-4.4)

11.8

Sept. 30

18.9 (18.3-20.4)

3.3 (3.0-4.4)

12.5

Oct. 7

17.8 (17.1-18.4)

3.5 (3.0-4.8)

13.2

Oct. 14

17.2 (16.0-18.0)

4.4 (3.0-6.2)

14.4

Rome

A minimum of 3.0 for the starch index is recommended for harvesting, with current regional average of 3.3. Since the current firmness is testing well above 18 pounds—the recommended minimum firmness for long-term CA storage—harvest can be delayed to wait for better size, brix and skin color. The predicted harvest date for Rome for central Berrien County is Oct. 15. Approximately 50% of the Romes in the area have been harvested.

Rome maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 30

23.0 (23.0-23.2)

3.0 (3.0-3.0)

11.5

Oct. 7

21.7 (20.0-23.0)

3.0 (3.0-3.0)

11.8

Oct. 14

21.3 (21.0-22.0)

3.3 (3.0-4.0)

11.8

Braeburn

A minimum of 3.0 for the starch index is recommended for harvesting for fresh for Braeburn. Since the current firmness is testing well above 16 pounds—the recommended minimum firmness for long-term CA storage—harvest can be delayed to wait for better size, brix and skin color. The predicted harvest date for Braeburn for central Berrien County is Oct. 28.

Braeburn maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 30

23.8 (22.0-26.0)

2.2 (1.6-2.8)

10.4

Oct. 7

21.8 (20.0-23.0)

3.1 (2.6-3.8)

10.7

Oct. 14

21.9 (19.2-24.0)

3.7 (2.2-5.0)

11.1

Evercrisp (MAIA 1)

A minimum of 3.0 for the starch index is recommended for harvesting for fresh for Evercrisp, the current average is 3.6. The current firmness is testing 22.0 pounds at the Southwest Michigan Research and Extension Center in central Berrien County, well above the minimum of 18 pounds for best long-term CA storage—harvest can be delayed to wait for better size, brix and skin color. This variety is known for high brix levels, currently testing 16.2%.

Our best guess is this variety harvests about 15 days after Red Delicious, or approximately Oct. 15 this year for central Berrien County. This is a relatively new variety and so the optimal pressure and starch test readings are still not known. Changing of background color from green to a lighter green or slight yellow appears to be a good indicator of a mature apple.

Evercrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 30

24.0

3.0

14.5

Oct. 7

21.0                       

3.6

16.2

Oct. 14

21.4

4.0

16.3

 

Normal and predicted 2019 peak harvest dates for apple varieties in central Berrien County in southwest Michigan based on weather data at the Southwest Michigan Research and Extension Center, Benton Harbor, MI.

Variety

Normal date

2018 Predicted peak harvest date

2019 Predicted peak harvest date

Paula Red

Aug. 22

 Aug. 20

Aug. 28

Zestar

Aug. 22

 Aug. 20

Aug. 28

Gingergold

Aug. 20

 Aug 18

Aug. 26

McIntosh

Sept. 10

 Sept 8

Sept. 16

Gala

Sept. 8

 Sept 6.

Sept. 14

Early Fuji

Sept. 3

 Sept. 1

Sept. 10

Honeycrisp

Sept. 13

 Sept. 13

Sept. 20

Empire

Sept. 19

 Sept. 23

Sept. 26

Jonathan

Sept. 22

 Sept. 24

Sept. 30

Jonagold

Sept. 22

 Sept. 24

Sept. 30

Golden Delicious

Sept. 25

 Sept. 27

Oct. 1

Red Delicious

Sept. 28

 Oct. 1

Oct. 7

Ida Red

Oct. 5

 Oct. 8

Oct. 15

Rome

Oct. 5

 Oct. 8

Oct. 15

Fuji

Oct. 20

 Oct. 22

Oct. 28

Braeburn

Oct. 20

 Oct. 22

Oct. 28

Goldrush

Oct. 26

 Oct. 28

Nov. 3

 

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

Braeburn

16

17

18

3.0

7.0

*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.)

 


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