Southwest Michigan apple maturity report – September 30, 2015

This is the weekly report of the MSU apple maturity program for southwest Michigan.

General comments for this week

We have had good weather for harvesting over the past week. The last of the few Gala, Jonathan and Honeycrisp still remaining are being picked for local sales.

The focus for growers in southwest Michigan over the past week has been harvesting Golden Delicious followed by Red Delicious. Crop loads are relatively good for Red Delicious, with some orchards over-cropped.

Woolly apple aphids are relatively more common on apple limbs this year.

Detailed tests for this week – see suggested firmness and starch levels for harvest in Table 1

This is the fourth week of Empire testing. The predicted long-term storage harvest date for 2015 in central Berrien County is Sept. 18. The average firmness this week was 16.3, still above 16 pounds, the minimum firmness for long-term CA storage. Starch indices this week averaged 4.5, sufficient for all fresh and processing uses. As is typical with this variety, the rate of firmness decrease has slowed.

Empire

Date picked

Firmness (pounds)

Starch

Brix

9/8/2015 - Average

19.0

2.2

10.3

9/14/2015 – Average

17.7

2.7

10.8

9/21/2015 - Average

17.1

3.6

11.9

9/28/2015

16.4

4.2

12.3

9/28/2015

16.4

4.2

13.5

9/28/2015

16.1

5.0

13.0

9/28/2015 - Average

16.3

4.5

12.9

This is the third report for Golden Delicious. Fruit firmness this week tested 17.3 pounds with starch removal index of 4.8. Golden Delicious has a predicted harvest date for long-term storage of Sept. 28 for Berrien County. Golden Delicious has a target firmness of at least 17 pounds for long-term CA storage and starch index of 3 for flavorful short-term direct sales. All sites are testing at the maturity stage and sufficient starch conversion for long-term CA storage for fresh sales. Firmness for two sites out of seven tested was below the 17 pounds recommended for long-term CA storage.

Golden Delicious

Date picked

Firmness (pounds)

Starch

Brix

9/14/2015 – Average

18.6

1.8

12.0

9/21/2015 – Average

17.6

2.9

12.2

9/28/2015

15.3

6.6

13.2

9/28/2015

16.2

5.6

13.4

9/28/2015

19.0

4.2

16.1

9/28/2015

19.0

3.2

13.5

9/28/2015

16.2

5.0

13.9

9/28/2015

18.0

4.0

14.1

9/28/2015 – Average

17.3

4.8

14.0

This is the third report for Red Delicious. Fruit firmness this week tested 17.4, slightly less than last week’s 17.6 pounds with starch removal index now averaging 3.1. Red Delicious has a target firmness of 18 or more pounds and starch index of 2.5 for successful long-term CA storage. This variety is running ahead of the predicted harvest date of Oct. 4 for Berrien County for long-term CA storage.

Red Delicious

Date picked

Firmness (pounds)

Starch

Brix

9/14/2015 – Average

17.9

2.3

9.4

9/21/2015 – Average

17.6

2.8

9.9

9/28/2015

17.0

2.8

12.6

9/28/2015

18.0

2.2

11.1

9/28/2015

17.0

4.0

10.8

9/28/2015

18.0

4.0

12.1

9/28/2015

17.0

2.6

11.8

9/28/2015 – Average

17.4

3.1

11.7

This is the second report for Ida Red. Fruit firmness this week tested 16.8 pounds with starch removal index 2.8. Ida Red has a target firmness of 16 or more pounds for successful long-term CA storage and starch index at 3.5 or above for good flavor for more immediate consumption. The decline of Ida Red firmness was only about 0.5 pounds over the past week, so the predicted harvest date for long-term CA storage for central Berrien County of Oct. 3 looks to be about right.

Ida Red

Date picked

Firmness (pounds)

Starch

Brix

9/21/2015 – Average

17.3

2.3

11.3

9/28/2015

17.0

2.8

11.6

9/28/2015

16.0

2.4

10.9

9/28/2015

17.0

3.0

12.7

9/28/2015

17.0

3.0

13.5

9/28/2015 – Average

16.8

2.8

12.2

This is the first report for Rome. Fruit firmness this week averaged 21.2 pounds with starch conversion index of 2.9. The target firmness for long-term storage is at least 18 pounds, and recommended starch index for direct sales is 3.0 or higher. Harvesting of Rome for processing has been in progress for the past two weeks. Actual mature date for central Berrien County is predicted to be Oct. 5.

Rome

Date picked

Firmness (pounds)

Starch

Brix

9/28/2015

20.0

3.0

11.5

9/28/2015

21.0

3.0

12.5

9/28/2015

22.4

2.6

12.5

9/28/2015

21.3

3.0

11.1

9/28/2015 – Average

21.2

2.9

11.9

This is the first report for Fuji. Fruit firmness this week tested 18.2 with a starch removal index of 3. Fuji has a target firmness of at least 18 pounds for long-term CA storage and minimum starch index of 3 for more immediate direct sales. Predicted harvest dates for Fuji for central Berrien County is Oct. 20. This variety typically softens slowly and brix increase seems to be triggered by cooler weather.

Fuji

Date picked

Firmness (pounds)

Starch

Brix

9/28/2015

18.0

3.0

13.1

9/28/2015

17.4

4.4

13.3

9/28/2015

18.0

2.8

12.0

9/28/2015

17.4

3.0

11.0

9/28/2015

20.0

3.4

12.9

9/28/2015 – Average

18.2

3.3

12.5

 

Table 1. 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.)

Normal and 2015 peak harvest dates for varieties for the Berrien County area in southwest Michigan

Variety

Relative days -/+ Redchief

Normal date

2015 predicted date

Lodi

-60

July 23

N/A

Pristine

-55

July 28

N/A

Williams Pride

-50

Aug. 2

N/A

Gingergold

-32

Aug. 20

Aug. 20

Paulared

-30

Aug. 22

Aug. 18

Zestar

-30

Aug. 22

Aug. 18

Gala

-23

Sept. 8

Sept. 7

Early Fuji strains

-23*

Sept. 3*

Sept. 3*

McIntosh

-20

Sept. 10

Sept. 6

Honeycrisp

-15*

Sept. 13

Sept. 9

Empire

-10

Sept. 18

Sept. 18

Jonathan

-10

Sept. 22

Sept. 23

Jonagold

-10

Sept. 22

Sept. 23

Golden Delicious

-4

Sept. 25

Sept. 26

Red Delicious

0

Sept. 28

Oct. 4

Idared

+5

Oct. 5

Oct. 5

Rome

+10

Oct. 5

Oct. 5

Fuji

+15

Oct. 20

Oct. 20

Braeburn

+15

Oct. 20

Oct. 20

Goldrush

+21

Oct. 26

Oct. 26

* Indicates revised dates

The samples for these reports are collected primarily in Berrien and Van Buren counties – the maturity is only a broad indication of trends for this area. Sites north of here, closer to Lake Michigan, on heavier soils or with heavier crop loads will generally harvest later.

Contact Bill Shane at the Southwest Michigan Research and Extension Center (SWMREC), 269-944-1477 ext. 205 or 269-208-1652, if you would like to have samples from your farm tested for maturity. Statewide reports will generally be available on the Michigan State University Extension Apple Maturity page by Wednesday afternoon each week.

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

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