Southwest Michigan apple maturity report – Oct. 21, 2020

End of season apple varieties Braeburn, Rome and Evercrisp still have excellent firmness.

Evercrisp apples
Evercrisp apples with great color. The parents are Honeycrisp and Fuji. Like Fuji, fruit quality and appearance of this variety is greatly improved by proper fruit thinning and good exposure to light. Photo by Bill Shane, MSU Extension.

Last report of the season and acknowledgements

This will be the last southwest Michigan apple maturity report for the season. We wish to thank the following growers for allowing us to collect samples for this program: Steve Weckworth, Mark Epple, Kurt Weber, Ed Czuba, Dean Froelich, Kyle Weber, Bryan Bixby, Greg Prillwitz, Mike Piedt and Marc Willmeng. We also thank Diedrie Scholz for collecting and processing the samples at the Michigan State University Southwest Michigan Research and Extension Center. The support of the Michigan Apple Committee and Michigan Tree Fruit Commission is greatly appreciated.

General apple harvest comments

The apple season is winding down in southwest Michigan with harvesting in most orchards nearly or completely finished.

Internal watercore symptoms are increasingly more common on Rome, Fuji and Evercrisp. It is called “Mitsu” or honey in Japanese because it resembles the color of honey. Apples with watercore are valued as flavorful apples and widely accepted in Japan. Apples with significant amount of watercore generally have less storage life. Using Retain has been very successful in suppressing watercore symptoms by holding back the increase of internal ethylene and thereby slowing internal maturation of fruit.

Brown marmorated stink bug activity has decreased with the recent cool weather. In general, this insect has been less active in southwest Michigan for the past two growing seasons.

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.

The predicted harvest dates are based on temperatures from spring to 30 days after bloom and do not take into account summer temperatures which can push development earlier or later than predicted. Hot weather over the past 30 days has stimulated internal ethylene levels in apple fruit and pushed along apple development.

Apple maturity in southwest Michigan for apples harvested Oct. 19, 2020

Variety

Firmness lbs. (range)

Starch (range)

Brix %

IdaRed

16.4 (15.2-18.2)

3.6 (3.0-4.2)

13.7

Fuji

16.4 (15.0-17.0)

6.0 (5.4-6.6)

15.9

Braeburn

23.3 (22.0-24.0)

3.9 (3.0-4.4)

15.5

Evercrisp*

25.0 (22.5-28.0)

3.8 (3.0-5.0)

15.5

Rome

20.1 (18.0-21.0)

5.3 (3.8-6.4)

12.8

* Based on sample from one orchard

Individual variety results

IdaRed was sampled for the fifth week. Starch conversion averaged 3.6, with 3.5 as the target for mature for this variety. Fruit firmness this week averaged 16.4 pounds, slightly below last week with the general guideline of 16 pounds minimum firmness for best long-term controlled atmosphere (CA) storage. The predicted peak harvest date is Oct. 7 for central Berrien County. There is a wide range of apple firmness, so harvest decision will be on a block to block decision basis. Maturity readings over the last few weeks have been pretty stable.

IdaRed maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 21

19.0 (18.0-21.0)

1.6 (1.0-2.2)

12.3

Sept. 28

18.4 (16.4-20.0)

2.5 (2.0-3.0)

11.9

Oct. 5

16.9 (15.4 – 18.4)

3.9 (2.8–6.8)

13.3

Oct. 12

16.7 (15.4-19.0)

3.4 (3.0-3.8)

13.1

Oct. 19

16.4 (15.2-18.2)

3.6 (3.0-4.2)

13.7

Fuji was sampled for the fourth week. Starch conversion averaged 6.0, quite a jump from last week’s 4.5, with 3.0 as the target for mature for this variety. Fruit firmness this week averaged 16.4 again about one pound less than last week, with the general guideline of 17 pounds minimum firmness for best long-term CA storage. The internal starch reading indicates that this variety has been internally mature more than two three week, with the brix continuing to increase and green tint disappearing from the peel. Watercore symptoms are becoming easier to find in this variety.

Fuji maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 28

19.1 (19.0-19.2)

3.1 (2.4-3.8)

13.5

Oct. 5

18.2 (16.0–21.0)

4.3 (4.0–4.6)

14.0

Oct. 12

17.3 (16.0-18.1)

4.5 (3.2-5.4)

14.9

Oct. 19

16.4 (15.0-17.0)

6.0 (5.4-6.6)

15.9

Braeburn was sampled for the fourth time. Starch conversion averaged 3.9, with 3.0 as the target for mature for this variety. Fruit firmness this week averaged 23 pounds, same as last week with the general guideline of 18 pounds minimum firmness for best long-term CA storage. The predicted peak harvest date is Oct. 28 for central Berrien County. This variety was internally mature beginning about Oct. 12. Watercore is slowly increasing.

Braeburn maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 28

24.0 (23.1-25.0)

2.4 (1.8-3.0)

11.6

Oct. 5

23.7 (23.0–25.0)

2.4 (2.0–3.0)

11.9

Oct. 12

23.4 (22.3-25.0)

3.1 (2.8-3.4)

12.7

Oct. 19

23.3 (22.0-24.0)

3.9 (3.0-4.4)

15.5

Evercrisp was sampled for the fourth time. Again, only one Berrien County orchard was available to sample this week for this relatively new variety. Starch conversion measured 3.8, appreciably higher than last week, with 3.0 as the target for mature for this variety. Fruit firmness this week averaged a very firm 25 pounds, very stable over the past three weeks, with the general guideline of 18 pounds minimum firmness for best long-term CA storage. Brix for the one orchard was 15.5, about the same as last week. Internally, these fruit are mature. Delayed harvest will allow time for fruit flesh acidity to reduce, and green peel flavor to subside, resulting in a better eating experience.

Evercrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 28

26.1 (25.2-27.0)

2.4 (1.8-3.0)

16.5

Oct. 5

26.2 (25.4–27.0)

2.6 (2.2–3.0)

17.2

Oct. 12*

26.0 (22.0-29.0)

2.6 (2.0-4.0)

15.6

Oct. 19*

25.0 (22.5-28.0)

3.8 (3.0-5.0)

15.5

* Based on one orchard

Rome was sampled for the third time. Starch conversion averaged 5.3, with 3.0 as the target for mature for this variety. Fruit firmness this week averaged 20.1 pounds, with the general guideline of 18 pounds minimum firmness for best long-term CA storage. The predicted peak harvest date for Romes in southwest Michigan is Oct. 7, which is approximately when the starch index was above 3.0.

Rome maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 5

21.3 (20.0–22.1)

3.5 (3.0–4.6)

13.0

Oct. 12

22.1 (20.0-23.0)

4.3 (3.8-5.2)

13.4

Oct. 19

20.1 (18.0-21.0)

5.3 (3.8-6.4)

12.8

 

Normal and predicted 2020 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 in Benton Harbor, Michigan.

Variety

Normal date

2019 Predicted peak harvest date

2020 Predicted peak harvest date

Paula Red

Aug. 22

Aug. 28

Aug. 25

Zestar

Aug. 22

Aug. 28

Aug. 25

Gingergold

Aug. 20

Aug. 26

Aug. 23

McIntosh

Sept. 10

Sept. 16

Sept. 13

Gala

Sept. 8

Sept. 14

Sept. 11

Early Fuji

Sept. 3

Sept. 10

Sept. 6

Honeycrisp

Sept. 13

Sept. 20

Sept. 15

Empire

Sept. 19

Sept. 26

Sept. 21

Jonathan

Sept. 22

Sept. 30

Sept. 24

Jonagold

Sept. 22

Sept. 30

Sept. 24

Golden Delicious

Sept. 25

Oct. 1

Sept. 27

Red Delicious

Sept. 28

Oct. 7

Sept. 30

Ida Red

Oct. 5

Oct. 15

Oct. 7

Rome

Oct. 5

Oct. 15

Oct. 7

Fuji

Oct. 20

Oct. 28

Oct. 22

Braeburn

Oct. 20

Oct. 28

Oct. 22

Goldrush

Oct. 26

Nov. 3

Oct. 28

 

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 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.)

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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