Southwest Michigan apple maturity report – September 23, 2015

Sunshine and cooler evenings are promoting good apple ripening. Golden Delicious harvest for processing is underway with Red Delicious harvest next on the horizon.

General comments for this week

We will have no more reports this season for Gala, McIntosh and early Fuji as most have been picked in the Berrien County area due to the advanced maturity. Honeycrisp are nearly done except for blocks in cooler sites, heavier crops or heavier soil.

The current sunny days and cooler nights have been very good for developing good color and maturity and for getting picking done. Stop drop treatments with Retain and NAA are generally working well this year because trees are generally not under stress. Some apple drop has occurred due to pushoffs because of crowded apple growth. Stop drop will not prevent this.

Most of the Jonagold, Jonathan and Empires have been harvested in Berrien County. A few Earlichief Red Delicious have been picked, but most Red Delicious harvesting is waiting for Golden Delicious picking for processing to be done.

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

This is the third 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 17.1, still above 16 pounds, the minimum firmness for long-term CA storage. Starch indices this week averaged 3.6, sufficient for all fresh and processing uses.

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

17.0

3.2

11.5

9/21/2015

17.0

5.0

13.3

9/21/2015

16.3

3.8

12.4

9/21/2015

18.0

3.0

10.7

9/21/2015

17.0

3.2

11.4

9/21/2015 - Average

17.1

3.6

11.9

This is the second report for Jonagold. Fruit firmness this week averaged 16.4 pounds, sufficient for midterm CA storage. Average starch removal index moved from 4.3 last week to 6.1 this week. Jonagold are ahead of the predicted harvest date of Sept. 23 for long-term CA storage. The target firmness for long-term storage is at least 17 pounds, and recommended starch index for direct sales is 3.5 or higher.

Jonagold

Date picked

Firmness (pounds)

Starch

Brix

9/14/2015 – Average

17.2

4.3

12.0

9/21/2015

16.4

6.6

11.3

9/21/2015

17.0

3.2

11.1

9/21/2015

16.0

7.0

13.1

9/21/2015

16.1

7.0

12.6

9/21/2015

16.3

7.0

12.0

9/21/2015

16.0

6.4

11.8

9/21/2015

17.3

5.6

14.5

9/21/2015 – Average

16.4

6.1

12.3

This is the second report for Jonathan. Fruit firmness this week tested 16.5, nearly 2 pounds less than last week, with a starch removal index of 4.9. It appears Jonathan are maturing close to the predicted harvest date for long-term storage of Sept. 23 for Berrien County. Jonathan has a target firmness of at least 16 pounds for long-term CA storage and a minimum starch index of 3.5 for more immediate successful direct sales.

Jonathan

Date picked

Firmness (pounds)

Starch

Brix

9/14/2015 – Average

18.6

3.6

12.2

9/21/2015

17.0

5.8

12.1

9/21/2015

16.1

4.8

11.9

9/21/2015

17.0

2.8

10.5

9/21/2015

16.0

5.8

12.4

9/21/2015

16.4

5.4

11.5

9/21/2015 – Average

16.5

4.9

11.7

This is the second report for Golden Delicious. Fruit firmness this week tested 17.6 pounds with starch removal index of 2.9. 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 desired for long-term CA storage and a starch index of 3 for flavorful, short-term direct sales. Some sites are testing at the maturity stage for long-term CA storage for fresh sales.

Golden Delicious

Date picked

Firmness (pounds)

Starch

Brix

9/14/2015 – Average

18.6

1.8

12.0

9/21/2015

17.0

4.4

11.4

9/21/2015

18.0

1.4

11.1

9/21/2015

18.2

1.6

13.3

9/21/2015

17.2

4.4

12.4

9/21/2015

17.0

3.6

12.3

9/21/2015

18.0

2.2

12.5

9/21/2015 – Average

17.6

2.9

12.2

This is the second report for Red Delicious. Recent sunny weather has helped red blush development. Fruit firmness this week tested 17.6, slightly less than last week’s 17.9 pounds with starch removal index now averaging 2.8. Red Delicious has a target firmness of 18 or more pounds and starch index of 2.5 for successful long-term CA storage. It appears 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

18.0

2.8

9.7

9/21/2015

17.0

3.0

8.4

9/21/2015

17.4

3.6

10.8

9/21/2015

19.0

2.0

10.7

9/21/2015

16.4

2.4

9.7

9/21/2015 – Average

17.6

2.8

9.9

This is the first report for Idared. Fruit firmness this week tested 17.3 pounds with starch removal index 2.3. Idared 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. Test indicate that maturity of Idared is running slightly ahead of the predicted harvest date for long-term CA storage for central Berrien County of Oct. 3.

Idared

Date picked

Firmness (pounds)

Starch

Brix

9/21/2015

17.0

2.0

11.4

9/21/2015

19.0

2.0

12.5

9/21/2015

17.0

2.8

10.5

9/21/2015

16.0

2.2

10.6

9/21/2015 – Average

17.3

2.3

11.3

 

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

*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, or with Retain or Harvista treatments 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.

Related Events

Related Articles

Related Resources