Southwest Michigan apple maturity report – Sept. 29, 2021

This is the fifth weekly apple maturity report for the southwest Michigan region.

Green apples hanging from a tree.
Golden Delicious harvest is well underway in southwest Michigan. Photo by Bill Shane, MSU Extension.

This apple maturity report for the southwest Michigan region is sent out every week (usually on Wednesdays) following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning.

Highlights for this week

Attention is focusing on harvesting Golden Delicious in southwest Michigan. About 50% of the Golden Delicious, and most of the Ida Red and Empire have been picked. Next variety to be targeted is Red Delicious.

Early maturing varieties, dry weather and lighter than normal crops have allowed harvesting to proceed rapidly.

Michigan State University horticulture professor Randy Beaudry wrote a helpful summary of MCP-1 sources.

Detailed information by variety

Mac, Gala, Honeycrisp, Jonagold, Jonathan

No more reports for these three varieties, now at full maturity.

Empire

This variety was sampled for the fourth week. Firmness decreased about 1 pound since last week, now at an average of 15.4 pounds, more appropriate for medium duration controlled atmosphere (CA) storage. Starch conversion has reached 5.0, well into the mature zone. Brix is averaging 12.9% and suitable for direct sales. The predicted harvest date for first significant harvest for central Berrien County is Sept. 21, an accurate prediction. Most Empires for processing have been picked.

Empire – Sampled Sept. 28, 2021

Site

Firmness (lbs.)

Red color range (%)

Starch

Soluble solids (°Brix)

1

14.0

40-90

5.6

12.0

2

14.3

100

5.4

12.0

3

17.0

100

4.4

13.9

4

15.3

98-100

4.8

13.5

5

16.4

70-98

4.6

13.1

Average

15.4

 

5.0

12.9

Max

17.0

 

5.6

13.9

Min

14.0

 

4.4

12.0

Recommended

16-14

 

3.5

 

 

Empire maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 7

19.4 (17.4-22.1)

2.9 (2.0-4.0)

11.2

Sept. 13

17.5 (16.2-20.0)

3.4 (3.0-4.2)

11.2

Sept. 20

16.3 (16.0-17.0)

3.8 (3.4-5.2)

12.3

Sept. 27

15.4 (14.0-17.0)

5.0 (4.4-5.6)

12.9

Golden Delicious

This variety was sampled for the 3rd week. Firmness is testing an average of 16.8 pounds compared to 17.4 for last week. This is at the lower range considered ideal for long term CA storage. Starch conversion average jumped from 3.5 to 4.4, and well above the 3.0 point where fruit is mature. This variety appears to be slightly ahead of the predicted harvest date of Sept. 28 for central Berrien County.

Golden Delicious – Sampled Sept. 28, 2021

Site

Firmness (lbs)

Red color range (%)

Starch

Soluble solids (°Brix)

1

18

5-15

3.6

15.5

2

18

15-30

3.0

16.4

3

17

0

5.0

13.8

4

16

15-40

4.8

13.4

5

15

20-30

5.8

12.3

Average

16.8

 

4.4

14.3

Max

18.0

 

5.8

16.4

Min

15.0

 

3.0

12.3

Recommended

17-15

 

3.0

 

 

Golden Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 13

17.6 (16.0-20.0)

2.9 (1.0-4.2)

12.0

Sept. 20

17.4 (16.0-19.1)

3.5 (2.6-4.8)

13.1

Sept. 27

16.8 (15.0-18.0)

4.4 (3.0-5.8)

14.3

Red Delicious

This variety was sampled for the third week. Firmness is testing an average of 16.4, approximately 2 pounds lower than last week, and below the recommended range for long term CA storage. Starch conversion for the five sites tested an average of 4.2, compared to 3.8 for last week, and well into the internally mature zone. This variety appears to be almost two weeks ahead of the predicted harvest date, which is Oct. 3 for central Berrien County.

Red Delicious – Sampled Sept. 28, 2021

Site

Firmness (lbs)

Red color range (%)

Starch

Soluble solids (°Brix)

1

16.0

100

4.6

13.1

2

17.3

100

3.2

11.2

3

17.0

100

3.0

11.7

4

17.0

95-100

4.6

13.4

5

15.0

80-98

5.6

12.2

6

16.3

100

4.0

12.5

Average

16.4

 

4.2

12.4

Max

17.3

 

5.6

13.4

Min

15.0

 

3.0

11.2

Recommended

18-16

 

2.5

 

 

Red Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 13

18.4 (17.2-20.2)

2.8 (2.0-4.0)

10.2

Sept. 20

17.4 (16.2-19.0)

3.8 (2.6-6.0)

11.4

Sept. 27

16.4 (15.0-17.3)

4.2 (3.0-5.6)

12.4

Fuji

This variety was sampled for the third week, and flesh firmness is testing an average of 16 pounds, almost 3 pounds lower than last week and in the lower end range recommended for fruit for CA storage. Starch conversion tested 4.3, compared to 3.0 for last week and considered to be internally mature. Red blush ranges from 15 to 95%.

So far, samples we have tested have been free of watercore. This is often an issue with fruit harvested past optimum maturity and in seasons with temperature extremes that stress fruit. Fuji has a revised predicted harvest date of Sept. 28 for central Berrien County. The revised harvest date seems correct for central Berrien County.

Fuji (Main season) – Sampled Sept. 28, 2021

Site

Firmness (lbs)

Red color range (%)

Starch

Soluble solids (°Brix)

1

16.1

15-95

4.6

12.6

2

17.0

40-85

4.2

13.8

3

17.0

65-95

3.0

13.4

4

15.0

60-90

3.8

12.5

5

15.0

25-50

6.0

13.3

Average

16.0

 

4.3

13.1

Max

17.0

 

6.0

13.8

Min

15.0

 

3.0

12.5

Recommended

18-16

 

3.0

 

 

Fuji maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 13

17.5 (16.2-20.0)

3.4 (3.0-4.2)

11.2

Sept. 20

19.0 (16.1-21.0)

3.0 (2.0-4.0)

12.6

Sept. 27

16.0 (15.0-17.0)

4.3 (3.0-4.3)

13.1

Ida Red

This variety was harvested for the second week and was predicted to be ready for fresh market harvesting approximately Oct. 10 in central Berrien County. Fruit firmness dropped 2 pounds since last week and is nearly at the point (16 pounds) that medium duration CA is more appropriate. Starch conversion is now testing an average of 3.6, the point this variety is considered internally mature. According to these tests, Ida Red harvest for longer duration CA storage should be underway. Some blocks have been harvested for processing.

Ida Red – Sampled Sept. 28, 2021

Site

Firmness (lbs)

Red color range (%)

Starch

Soluble solids (°Brix)

1

16.0

60-90

2.8

12.2

2

16.0

85-98

6.2

14.6

3

16.0

40-75

3.4

10.7

4

18.2

85-90

2.6

13.9

5

18.0

85-95

3.0

12.9

Average

16.0

 

3.6

12.9

Max

17.0

 

6.2

14.6

Min

15.0

 

2.6

10.7

Recommended

16-14

 

3.5

 

 

IdaRed maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 20

18.1 (16.1-20.0)

2.0 (1.0-2.8)

12.6

Sept. 27

16.0 (15.0-17.0)

3.6 (2.6-6.2)

12.9

Rome

This variety was harvested for the first time this week and is predicted to be ready approximately Oct. 10 in central Berrien County. Fruit firmness is still excellent at an average of 18.1 pounds, with starch conversion testing an average of 2.0, still well below the 3.5 considered internally mature. According to these tests, Rome harvest can be delayed. Some blocks have been harvested for processing.

Rome – Sampled Sept. 28, 2021

Site

Firmness (lbs)

Red color range (%)

Starch

Soluble solids (°Brix)

1

22.0

50-80

3.2

11.1

2

19.2

60-98

3.8

12.0

3

22.4

45-90

3.0

11.1

4

20.3

40-60

4.0

11.4

Average

21.0

 

3.5

11.4

Max

22.4

 

4.0

12.0

Min

19.2

 

3.0

11.1

Recommended

18-15

 

3.5

 

Braeburn

This variety was harvested for the first time this week. and is predicted to be ready approximately Oct. 27 in central Berrien County. Fruit firmness is excellent at an average of 21.1 pounds, with starch conversion testing an average of 2.9, below the 3.5 considered internally mature. Starch tests for the sites ranged from 1.4 to 4.0, indicating a significant differences in maturity at different farms.

Braeburn – Sampled Sept. 28, 2021

Site

Firmness (lbs)

Red color range (%)

Starch

Soluble solids (°Brix)

1

20.3

35-65

3.6

11.4

2

21.0

15-20

2.4

10.2

3

22.0

40-85

4.0

10.8

4

21.0

30-60

1.4

11.0

Average

21.1

 

2.9

10.9

Max

22.0

 

4.0

11.4

Min

20.3

 

1.4

10.2

Recommended

18-15

 

3.5

 

Additional notes

Evercrisp (two sites tested) is now averaging 21.5 pounds firmness., compared to 25 pounds last week. The starch index is averaging 2.5, up from last week’s 1.0, and brix 13.5% compared to 12.2 of last week. We don’t have specific guidelines for Evercrisp maturity but will use those for Fuji parent—firmness recommendation 18 pounds for long term CA down to 16 pounds for short term CA and minimum starch index of 3. Penn State University recommends using starch index of 4-6 for long term storage and 6-7 for direct sales market.

This variety is still testing immature. Evercrisp, like Fuji, is prone to watercore and internal browning in storage if picked too late, so keeping an eye on the starch index is recommended.

How to read the maturity tables

For each variety evaluated, each row in the data table is a different orchard block. Maximum and minimum values are the highest and lowest individual fruits evaluated for each. Recommended values are included for each variety at the bottom of the table. These suggested values for firmness and starch index were also published in a standalone table format. Firmness ranges encompass long and short-term storage recommendations.

Firmness in pounds pressure = measured with a FT Penetrometer using a 7/16 inch (11 millimeters) diameter probe, peel removed; range is for the average at each site.

Starch: 1 = no starch conversion, 8 = No starch; range is for average of the sites. Using Cornell Starch Iodine Index Chart.

Brix = % sugar measured with Atago PAL-1 Pocket Refractometer

Additional apple maturity helps

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

 

Normal and predicted 2021 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 SW

2020 Predicted 1st significant harvest date

2021 Predicted 1st significant harvest date

Paula Red

22-Aug

25-Aug

13-Aug

Zestar

22-Aug

25-Aug

13-Aug

Gingergold

20-Aug

23-Aug

11-Aug

Early Fuji

3-Sep

6-Sep

25-Aug

Gala

8-Sep

11-Sep

31-Aug

McIntosh

10-Sep

13-Sep

1-Sep

Honeycrisp

13-Sep

15-Sep

4-Sep

Empire

18-Sep

21-Sep

21-Sep

Jonathan

22-Sep

24-Sep

25-Sep

Jonagold

22-Sep

24-Sep

25-Sep

Fuji

25-Sep

28-Oct

28-Sep

Golden Delicious

25-Sep

27-Sep

28-Sep

Red Delicious

28-Sep

20-Sep

3-Oct

Ida Red

5-Oct

7-Oct

10-Oct

Rome

5-Oct

7-Oct

10-Oct

Braeburn

20-Oct

22-Oct

25-Oct

Goldrush

26-Oct

28-Oct

27-Oct

Please note that the predictions are for the first significant harvest date rather than peak harvest. Also note that the normal harvest date for Fuji is approximately three weeks ahead of the normal date given in previous years reports. Newer strains of Fuji have much earlier and more extensive red blush development than older strains. In the past, harvest of Fuji was delayed past optimum internal maturity to wait for better blush development. This delay has resulted in increased storage problems, including watercore and internal browning.

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