Southwest Michigan apple maturity report – Oct. 14, 2020

Late season apples such as Braeburn, Fuji and Evercrisp remain to be picked. U-pick and farm market sales have been brisk partly due to poorer crops in neighboring Indiana.

Desert Rose Fuji
Desert Rose Fuji showing excellent coloring. This year has been excellent for red blush development on apples. Photo by Bill Shane, MSU Extension.

General apple harvest comments

Red Delicious and IdaRed are essentially all picked and Fuji are nearly gone. Romes, Braeburn and Enterprise have had some harvests. Recent winds were responsible for some fruit drop. The southwest region is approximately one week ahead of the southeast and Grand Rapid, Michigan, regions due to higher heat unit accumulation

Brown marmorated stink bug activity increased with warming temperatures. Adults are starting to move into buildings. San Jose scale can be seen here and there on fruit from older orchards where rough bark and abundant crevices make control of this insect more difficult.

Watercore symptoms are increasingly more common and overmature smell characteristics are becoming evident on some Red Delicious not protected with Retain or Harvista treatments. Bright, sunny weather tends to increase watercore tendency. Watercore often reduces or disappears in storage but also is correlated with poorer shelf life. It can weaken fruit and cause future problems, including CO2 injury in storage. Orchards and varieties starting to show watercore should be higher priorities for harvesting, assuming they are sufficiently mature.

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. 12, 2020

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Red Delicious

15.3 (14.0-16.4)

5.8 (5.6-6.0)

15.1

IdaRed

16.7 (15.4-19.0)

3.4 (3.0-3.8)

13.1

Fuji

17.3 (16.0-18.1)

4.5 (3.2-5.4)

14.9

Braeburn

23.4 (22.3-25.0)

3.1 (2.8-3.4)

12.7

Evercrisp*

26.0 (22.0-29.0)

2.6 (2.0-4.0)

15.6

Rome

22.1 (20.0-23.0)

4.3 (3.8-5.2)

13.4

* Based on sample from one orchard

Individual variety results

Red Delicious was sampled for the fifth week. Starch conversion this week is averaging 5.8, a sizable increase over last week 4.7, with 2.5 as the target for mature for this variety. Fruit firmness this week averaged 15.3, with the general guideline of a minimum of 16 pounds firmness for short-term controlled atmosphere (CA) storage. This variety is well beyond the peak harvest point. Watercore symptoms are easily found in all orchards sampled.

Red Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 14

18.7 (18.1-19.0)

2.1 (1.8-2.4)

11.9

Sept. 21

18.1 (17.4-19.0)

2.9 (2.6-3.0)

11.9

Sept. 28

18.0 (17.1-19.0)

4.0 (3.2-4.6)

13.4

Oct. 5

16.6 (16.2 – 17.0)

4.7 (4.2–5.6)

14.6

Oct. 12

15.3 (14.0-16.4)

5.8 (5.6-6.0)

15.1

IdaRed was sampled for the fourth week. Starch conversion averaged 3.4, with 3.5 as the target for mature for this variety. Fruit firmness this week averaged 16.7 pounds, about the same as last week with the general guideline of 16 pounds minimum firmness for best long-term 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.

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

Fuji was sampled for the third week. Starch conversion averaged 4.5, with 3.0 as the target for mature for this variety. Fruit firmness this week averaged 17.3 pounds, about 1 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 is mature enough across the region to harvest. Newer strains of Fuji such as Aztec, Brak and Supreme with more red skin color are attractive enough to harvest. Harvest of older strains, particularly in cloudy autumns, are often delayed by growers to wait for more red skin color development. 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

Braeburn was sampled for the third time. Starch conversion averaged 3.1, with 3.0 as the target for mature for this variety. Fruit firmness this week averaged 23 pounds, 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. Watercore is starting to show up in some fruit.

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

Evercrisp was sampled for the third time. Only one orchard was available to sample this week. Starch conversion measured 2.6, the same as last week, with 3.0 as the target for mature for this variety. Fruit firmness this week averaged a very firm 26 pounds, the same as the last two weeks with the general guideline of 18 pounds minimum firmness for best long-term CA storage. Brix for the one orchard was 15.6. Skin red blush was already decent at the site. Excellent firmness will permit harvesting to be delayed for less firm fruit, higher brix and internal starch development. Delayed harvest will also allow time for fruit flesh acidity to reduce, 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

* Based on one orchard

Rome was sampled for the second time. Starch conversion averaged 3.5. All four sites tested averaged 4.3 with 3.0 as the target for mature for this variety. Fruit firmness this week averaged 21.3 pounds, with the general guideline of 18 pounds minimum firmness for best long-term CA storage. Predicted peak harvest date for southwest Michigan is Oct. 7.

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

 

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* see Fuji section in report

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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