Southwest Michigan apple maturity report – Sept. 26, 2018

Sunny days and cooler nighttime temperatures are helping to increase sugar content and red blush of area apples.

September 26, 2018 - Author:

General apple harvest comments

Growers are finishing up harvests of Empire and Jonagold in SW Michigan. Some growers are turning their attention to Golden Delicious for processing, and a few early strain Red Delicious have been harvested. In 2018 we have seen certain varieties such as Gala, Honeycrisp, and Fuji “pushed ahead” by warmer than average temperatures in this year. The recent dry weather has generally cooperated with harvesting activity.

Brown marmorated stink bug adults are widespread in the area, but significantly damaging fruit only in a few sites. Orchard sides close to woods, soybean fields, ravines and where natural hosts such as buckthorn, tree of heaven and mulberry have served as food sources for stink bug multiplication and clustering. Some gathering of stink bugs on sunny sides of buildings has begun, maybe triggered by cooler nights and harvesting of infested soybean fields.

More sooty blotch and flyspeck are showing up on fruit in area orchards, more than we generally see at this point in the harvest season. Bitter pit and lenticel rot seems to be less concerns this year.

Samples we collect 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. Apples harvested for processing are often picked less ripe than those for fresh sales. Apples slated for short-term storage and quick consumption can be picked later for better flavor.

Apple maturity in southwest Michigan for apples harvested Sept. 24

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Jonagold

18.2 (17.1-19.8)

5.9 (4.2-7.0)

13.2

Empire

17.5 (17.2-18.9)

3.8 (3.4-4.4)

11.8

Golden

17.4 (15.3-19.8)

4.2 (3.6-5.8)

11.7

Red Delicious

17.3 (16.0-18.3)

3.5 (3.0-4.0)

10.3

IdaRed

17.9 (17.0-19.8)

2.1 (1.8-2.6)

10.9

Fuji

19.5 (17.5-20.4)

3.4 (2.8-3.8)

12.0

Individual variety results

Jonagold was sampled for the third time this season. Starch conversion is averaging 5.9, another jump from the average of 4.8 for last week, with 3.5 as the target for mature for this variety. The predicted peak harvest date is Sept. 24 for central Berrien County, which seems to indicate this variety is maturing slightly ahead of prediction. Brix for this week is 13.2. Fruit firmness averaged 18.2 pounds about the same as last week, with the general guideline of a minimum of 17 pounds firmness for best long-term CA storage. The starch test indicates fruit tested were mature, with newer red strains having sufficient color for fresh market.

Jonagold maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 11

19.5 (18.0-21.0)

2.3 (1.2-3.6)

11.4

Sept. 17

18.4 (17.0-20.0)

4.8 (3.4-6.0)

12.1

Sept. 24

18.2 (17.1-19.8)

5.9 (4.2-7.0)

13.2

Empire was sampled for the third week. Starch conversion is averaging 3.8 this week, with 3.5 as the target for mature for this variety. The predicted peak harvest date is Sept. 23 for central Berrien County. Brix for this week is 11.9. Fruit firmness averaged 17.5 pounds this week, about 1 pound less than last week with the general guideline of a minimum of 16 pounds firmness for best long-term CA storage. Based on these tests, fruit are suitable for fresh market harvest in orchards similar to these.

Empire maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 11

18.5 (18-20)

2.1 (1.8-2.6)

11.2

Sept. 17

18.7 (18.0-21.0)

2.8 (2.0-3.2)

11.9

Sept. 24

17.5 (17.2-18.9)

3.8 (3.4-4.4)

11.8

Golden Delicious was sampled for the third week. Starch conversion jumped again this week, reading 4.2, compared to 3.1 last week, with 3 as the target for mature for this variety. The predicted peak harvest date is Sept. 27 for central Berrien County. Brix for this week is 12.0. Fruit firmness averaged 17.4 pounds this week, about 1 pound less than last week with the general guideline of a minimum of 17 pounds for best long-term CA storage. As seems to be the case this year, watch this variety carefully as apples seem to be ripening slightly ahead of the predicted harvest date.

Golden Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 11

18.2 (16-20)

1.5 (1.0-2.4)

11.1

Sept. 17

18.5 (17.0-19.4)

3.1 (2.2-5.0)

12.0

Sept. 24

17.4 (15.3-19.8)

4.2 (3.6-5.8)

11.7

Red Delicious was tested for the second week. Starch conversion is averaging 3.5 this week, with 2.5 as the minimum for considering to be mature for this variety. The predicted peak harvest date is Oct. 1 for central Berrien County. Brix for this week is 10.3. Fruit firmness averaged 17.3 pounds this week, with the general guideline of 18 pounds for best long-term CA storage. Red skin color has improved greatly over the past week. Based on these tests some spot picking of more advanced maturity orchards could begin.

Red Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

18.0 (17.0-20.0)

2.9 (2.4-3.6)

10.1

Sept. 24

17.3 (16.0-18.3)

3.5 (3.0-4.0)

10.3

IdaRed were tested for a few area orchards this week. Starch conversion is averaging 2.1 this week compared to 1.5 for last week, with 3.5 as the minimum for mature for this variety. The predicted peak harvest date is Oct. 8 for central Berrien County. Brix for this week is 10.9, nearly the same as last week. Fruit firmness averaged 17.9 pounds this week, nearly 2 pounds less than last week. The general guideline is a minimum of 16 pounds for best long-term CA storage. This variety still has a ways to go before it is ready for picking.

IdaRed maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

19.5 (19.0-20.0)

1.5 (1.0-2.0)

11.1

Sept. 24

17.9 (17.0-19.8)

2.1 (1.8-2.6)

10.9

Fuji were tested for the first time this week. Starch conversion is averaging 3.4 this week, with 3.0 as the minimum for mature for this variety. Brix for this week is 12.0. Fruit firmness averaged 19.5 pounds this week, with the general guideline of a minimum of 18 pounds for best long-term CA storage. Background coloration is still relatively green, but maturity is relatively advanced and appears to be ahead of the predicted peak harvest date is Oct. 22 for central Berrien County.

Fuji maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 24

19.5 (17.5-20.4)

3.4 (2.8-3.8)

12.0

 

Normal and predicted 2018 peak harvest dates for apple varieties 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

Paula Red

Aug. 22

 Aug. 20

Zestar

Aug. 22

 Aug. 20

Gingergold

Aug. 20

 Aug 18

McIntosh

Sept. 10

 Sept 8

Gala

Sept. 8

 Sept 6.

Early Fuji

Sept. 3

 Sept. 1

Honeycrisp

Sept. 13

 Sept. 13

Empire

Sept. 19

 Sept. 23

Jonathan

Sept. 22

 Sept. 24

Jonagold

Sept. 22

 Sept. 24

Golden Delicious

Sept. 25

 Sept. 27

Red Delicious

Sept. 28

 Oct. 1

Ida Red

Oct. 5

 Oct. 8

Rome

Oct. 5

 Oct. 8

Fuji

Oct. 20

 Oct. 22

Braeburn

Oct. 20

 Oct. 22

Goldrush

Oct. 26

 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 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.)

Looking for more? View Michigan State University Extension’s Apple Maturity page for regional reports throughout the state and additional resources.

Tags: apple harvest 2018, apple maturity reports, east apple maturity report, msu extension


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