Southwest Michigan apple maturity report – October 7, 2015

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

General comments for this week

Good weather for harvesting is continuing. Fruit are attractive this year with generally good color skin color for newer redder strains. Harvesting of Golden Delicious, Red Delicious, Ida Red and some Fuji is underway. Fruit size is generally good. Some growers report some shortage of labor.

Reports of brown marmorated stink bug activity have decreased somewhat with cooler weather. Apple scab is becoming easier to see on leaves as natural resistance declines in the fall.

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

No more reports for Empire. Most in area are picked. This variety is very mature.

This is the fourth report for Golden Delicious. Fruit firmness this week tested 16.8 pounds with starch clearing index of 5.2. 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 mature for starch clearing (eating maturity). Firmness readings for four sites out of seven tested were below the 17 pounds minimum recommended for long-term CA storage. Pink blush is very common on the sun exposed side of fruit.

Golden Delicious

Date picked

Firmness (pounds)

Starch clearing

Brix

9/14/2015 – Average

18.6

1.8

12.0

9/21/2015 – Average

17.6

2.9

12.2

9/28/2015 – Average

17.3

4.8

14.0

10/5/2015

18.0

2.8

16.5

10/5/2015

16.2

3.8

15.3

10/5/2015

15.0

6.4

15.9

10/5/2015

16.0

6.0

13.4

10/5/2015

16.4

6.2

13.9

10/5/2015

17.0

6.4

15.7

10/5/2015

19.0

4.8

17.8

10/5/2015 – Average

16.8

5.2

15.5

This is the fourth report for Red Delicious. Fruit firmness this week tested 17.1, slightly less than last week’s 17.4 pounds with the starch clearing index now averaging 3.9. Red Delicious has a target firmness of 18 or more pounds and starch index of 2.5 for successful long-term CA storage. Some sites have firmness testing in the mid-term CA storage category. Vascular bundles at the core line are staining red in fruit of some highly colored Red Delicious strains. Eating quality has improved greatly over the past week with brix now averaging 12.4

Red Delicious

Date picked

Firmness (pounds)

Starch clearing

Brix

9/14/2015 – Average

17.9

2.3

9.4

9/21/2015 – Average

17.6

2.8

9.9

9/28/2015 – Average

17.4

3.1

11.7

10/5/2015

17.0

4.2

11.6

10/5/2015

16.3

4.0

13.3

10/5/2015

18.0

3.4

12.0

10/5/2015

17.2

4.2

12.3

10/5/2015

17.4

3.6

13.0

10/5/2015

17.4

4.0

12.6

10/5/2015

16.3

3.6

11.8

10/5/2015 – Average

17.1

3.9

12.4

This is the third report for Ida Red. Fruit firmness this week tested 15.6 pounds compared to 16.8 pounds for last week, with starch clearing index up to 4.0, compared to last week’s 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. Ida Red has reached sufficient starch conversion for good long-term CA storage for central Berrien County, with some sites with fruit firmness better suited for mid-term CA storage. Area growers have been busy harvesting Idared this week.

Ida Red

Date picked

Firmness (pounds)

Starch clearing

Brix

9/21/2015 – Average

17.3

2.3

11.3

9/28/2015 – Average

16.8

2.8

12.2

10/5/2015

16.0

3.4

14.5

10/5/2015

15.0

4.4

14.0

10/5/2015

16.1

3.0

12.3

10/5/2015

15.1

5.0

13.3

10/5/2015—Average

15.6

4.0

13.5

This is the second report for Rome. Fruit firmness this week averaged 20.6 compared to 21.2 pounds for last week with starch clearing index of 3.8 compared to 2.9 of last week. The target firmness for long-term storage is at least 18 pounds, and recommended starch index for direct sales is 3.0 or higher. Rome harvest for processing has been in progress for the past three weeks. All three sites tested had sufficient starch clearing and firmness for successful long-term CA. The mature date for this variety for central Berrien County is predicted to be Oct. 5.

Rome

Date picked

Firmness (pounds)

Starch clearing

Brix

9/28/2015 – Average

21.2

2.9

11.9

10/5/2015

20.3

4.4

13.1

10/5/2015

21.3

3.2

13.4

10/5/2015

20.3

3.8

12.9

10/5/2015—Average

20.6

3.8

13.1

This is the second report for Fuji. Fruit firmness this week tested 18.0, slightly less than last week, however with a starch clearing index jumping to 5.7, compared to last week’s 3.3. 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. Some blocks with newer, redder Fuji varieties may have sufficient internal maturity and good skin color to allow harvest for long-term CA storage. 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. Better eating quality is obtained by holding off harvesting until the background loses both the strong green color and the very smooth skin of an immature apple. The downside of delaying harvest of Fuji is that internal watercore may increase. So far, very little watercore has been seen in orchards sampled.

Fuji

Date picked

Firmness (pounds)

Starch clearing

Brix

9/28/2015 – Average

18.2

3.3

12.5

10/5/2015

18.4

7.0

14.3

10/5/2015

18.0

5.6

14.5

10/5/2015

18.0

3.4

14.4

10/5/2015

17.4

6.8

13.3

10/5/2015 – Average

18.0

5.7

14.1

This is the first report for Braeburn. Fruit firmness this week tested 20.4, with a starch clearing index of 2.9. Braeburn 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 Braeburn for central Berrien County is Oct. 20. Current fruit firmness will allow harvest to be delayed to wait for better brix, skin color and fruit size. Little amounts of watercore can be found in fruit in some orchards.

Braeburn

Date picked

Firmness (pounds)

Starch clearing

Brix

10/5/2015

21.0

2.0

11.7

10/5/2015

20.2

3.0

13.3

10/5/2015

20.4

2.6

12.4

10/5/2015

20.0

3.8

12.0

10/5/2015 – Average

20.4

2.9

12.4

 

Table 1. Suggested firmness and starch index levels for long-term and shorter-term controlled atmosphere (CA) storage by variety.

Variety

Firmness (pounds)*

Starch Clearing 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

7

*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 clearing 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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