Southwest Michigan apple maturity report – Oct. 2, 2019

Jonagold and Golden Delicious harvests are winding down, and Red Delicious is being targeted next.

General apple harvest comments

Harvesting of main season Red Delicious varieties is continuing. Some harvesting of Romes for processing is underway.

Samples collected for this report are from the central Berrien County region, targeting more mature fruit on the outside of the tree canopy. Fruit in the interior of the tree will be less advanced than shown here. Sites with heavier soils and greater crop loads will generally be less mature.

Apple maturity in southwest Michigan for apples harvested Oct. 1, 2019

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Jonagold

17.0 (16.0-18.1)

5.5 (5.2-5.8)

14.4

Golden Delicious

17.1 (16.0-19.0)

4.1 (2.0-5.0)

12.5

Red Delicious

16.5 (16.0-18.0)

3.5 (3.0-4.6)

10.9

Ida Red

17.3 (16.2-20.0)

2.2 (2.0-3.0)

11.3

Fuji (late season)

18.9 (18.3-20.4)

3.3 (3.0-4.4)

12.5

Rome

23.0 (23.0-23.2)

3.0 (3.0-3.0)

11.5

Braeburn

23.8 (22.0-26.0)

2.2 (1.6-2.8)

10.4

Evercrisp*

24.0

3.0

14.5

*Based on one site

Individual variety results

Jonagold 

Jonagold was sampled for the fourth week. Starch conversion this week is averaging 5.5, with 3.5 as the target for mature for this variety. Fruit firmness this week averaged 17.0 pounds, about 0.5 pounds less than last week, with the general guideline of a minimum of 17 pounds firmness for best long-term controlled atmosphere (CA) storage. The predicted peak harvest date is Sept. 30 for central Berrien County. This variety matured slightly ahead of the predicted date. Approximately 95% of the area Jonagold have been harvested.

Jonagold maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 10

19.3 (18.0-20.0)

2.4 (2.0-3.4)

11.6

Sept. 16

17.7 (17.0-18.4)

3.8 (3.0-4.8)

12.5

Sept. 23

17.6 (16.3-19.4)

5.6 (4.4-6.6)

13.8

Sept. 30

17.0 (16.0-18.1)

5.5 (5.2-5.8)

14.4

Golden Delicious 

Golden Delicious was sampled for the third week. Starch conversion this week is averaging 4.1, compared to 3.5 for last week, with 3 as the target for mature for this variety. Fruit firmness this week averaged 17.1 pounds and close to the general guideline of a minimum of 17 pounds firmness for best long-term CA storage. Starch conversion has caught up to fruit softening. Over 90% of the area Golden Delicious have been harvested.

Golden Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 16

17.5 (17.0-18.0)

1.6 (1.0-2.0)

11.4

Sept. 23

17.6 (16.0-19.0)

3.5 (2.8-4.0)

12.4

Sept. 30

17.1 (16.0-19.0)

4.1 (2.0-5.0)

12.5

Red Delicious 

Red Delicious was sampled for the second time. Fruit at 16.0 or lower are considered appropriate for short-term CA storage and more immediate consumption, with the average for this week testing at 16.5 pounds firmness. Starch conversion is now averaging 3.5, with a reading of 3.5 or greater considered sufficiently mature for harvesting. The predicted peak harvest date for Red Delicious in central Berrien County is Oct. 7. About half of the area’s Red Delicious have been harvested.

Red Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 23

17.1 (16.0-18.1)

3.3 (3.0-4.0)

10.7

Sept. 30

16.5 (16.0-18.0)

3.5 (3.0-4.6)

10.9

Ida Red

The current starch test average of 2.2 is still well below the mature threshold of 3.5. The minimum recommended firmness for long-term CA storage is 16 pounds, and Ida Red are currently averaging 17.3. The predicted harvest date for Ida Red in central Berrien County is Oct. 15.

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

Fuji (late-season varieties)

The current firmness is testing at 18.9 pounds, still 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 recommended minimum starch reading for maturity is 3.0, the current reading is 3.3. The predicted harvest date for Fuji for central Berrien County is Oct. 28.

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

Rome

A minimum of 3.0 for the starch index is recommended for harvesting, matching the current value of 3.0. 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. Harvesting of some fruit for processing is underway.

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

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

Cameo

A minimum of 3.0 for the starch index is recommended for harvesting for fresh. Current firmness is 20 pounds. Harvest can be delayed to wait for better size, brix and skin color. Other harvesting indicators are 50% red color (for original strain) and background beginning to change from green to cream white.

Cameo maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 30

20.0 (19.0-21.0)

2.5 (2.0-3.0)

12.3

Evercrisp (MAIA 1)

A minimum of 3.0 for the starch index is recommended for harvesting for fresh for Evercrisp, the current average is 2.4. The current firmness is testing 24.0 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 14.5. Our best guess is this variety harvests about 15 days after Red Delicious, or approximately Oct. 15 this year for central Berrien County.

Evercrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 30

24.0

3.0

14.5

 

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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