NOVEL CORONAVIRUS UPDATES AND RESOURCES

Southwest Michigan apple maturity report – Sept. 18, 2019

Gala harvest is winding down and Honeycrisp harvest continues in southwest Michigan.

General apple harvest comments

Recent rains have helped sizing of the apple crop. Most Galas, Empires and McIntosh have been harvested in the area. There still are many Honeycrisp yet to be harvested. Labor supplies seem to be generally adequate, in part due to the increased use of H2A labor.

Over the past week, the number of brown marmorated stink bugs in traps increased significantly in southern Michigan. Reports of damage to fruit crops have been few so far. Scouting of orchard borders, especially along woods and next to soybeans, is recommended to head off problems with this pest.

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 Sept. 16, 2019

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Honeycrisp

15.4 (14.0-16.2)

6.4 (4.6-8.0)

12.8

Early Fuji

16.5 (15.4-17.0)

4.7 (4.4-4.8)

14.3

Gala

19.7 (19.0-21.0)

4.7 (3.8-5.6)

12.0

Jonathan

17.4 (17.0-18.2)

3.3 (3.0-4.8)

11.4

Empire

18.6 (17.2-20.0)

2.9 (2.0-4.0)

11.3

Jonagold

17.7 (17.0-18.4)

3.8 (3.0-4.8)

12.5

Golden Delicious

17.5 (17.0-18.0)

1.6 (1.0-2.0)

11.4

Individual variety results

McIntosh

No new samples were taken this week because most have been harvested in the area. Predicted peak harvest date for central Berrien County is Sept. 16.

McIntosh maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 3

17.0 (17.0-17.0)

3.3 (3.0-3.6)

12.4

Sept. 10

16.0 (16.0-16.1)

3.6 (3.2-4.0)

12.0

Gala

Target starch index for maturity for this variety is 3. The current average is 4.7, with all sites testing above 3.0. Relative firmness is averaging 19.7, compared to 21 pounds for last week, with the minimum firmness of 18 pounds recommended for long-term controlled atmosphere (CA) storage. Predicted peak harvest date for central Berrien County is Sept. 14. Some fruit cracking has been noted for sites with advanced starch readings. Nearly all Galas have been harvested in the central Berrien County area. Skin color is good in many blocks. In general, quality is quite good.

Gala maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 3

21.1 (20.0-23.0)

2.7 (1.4-4.4)

10.8

Sept. 10

20.6 (18.3-23)

4.3 (2.0-6.4)

11.5

Sept. 16

19.7 (19.0-21.0)

4.7 (3.8-5.6)

12.0

Honeycrisp

The current average is 6.4, quite a jump from last week’s 3.8, with a target mature starch index of 3.5 for this variety. The current average firmness of 15.4 pounds, compared to 16.0 for last week, is below the general guideline of 17 pounds for best long-term CA storage. The predicted peak harvest date is Sept. 20 for central Berrien County. This variety is maturing ahead of the predicted date. Blocks with light crops, common in southwest Michigan this year, will generally harvest earlier than those with normal or heavier crops.

Leaf pruning has been done in some blocks with the original Honeycrisp strain to help improve fruit color. Fruit dropping has been a problem in blocks where stop drop sprays have not been applied, especially for large fruit. Bitter pit is relatively low this year. This is in part due to growers holding back on potassium fertilizer. The fungal disease bitter rot is more prevalent this year on this variety.

Honeycrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 3

18.3 (17.0-20.0)

2.5 (1.8-3.8)

12.0

Sept. 10

16.0 (14.0-19.2)

3.8 (1.6-6.2)

11.9

Sept. 16

15.4 (14.0-16.2)

6.4 (4.6-8.0)

12.8

Early Fuji

This is the third week of testing. A starch test of 3 is generally used as the target for mature for this variety, compared to the current average this week of 4.7. The general guideline is 18 pounds for best long-term CA storage, although this variety is generally used for direct fresh sales rather than long-term storage. The current average is 16.5 pounds. The predicted peak harvest date is Sept. 10 for central Berrien County, which seems to be about right this year.

Early Fuji maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 3

19.2 (19.0-19.4)

2.5 (3.0-4.0)

12.9

Sept. 10

18.8 (18.0-19.3)

4.4 (3.2-5.8)

13.5

Sept. 16

16.5 (15.4-17.0)

4.7 (4.4-4.8)

14.3

Jonathan

Jonathan was sampled for the second week. This variety is generally utilized as taffy apples, with less concern about reaching ideal maturity. The current average starch reading of 3.3 is nearly to the target minimum 3.5 for mature. Firmness is averaging 16.5 pounds, slightly above 16, the target for long-term CA storage. Jonathan development is pretty close to the predicted harvest date for fresh market for central Berrien County of Sept. 30.

Jonathan maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 10

19.0 (18.0-21.0)

3.0 (3.0-3.0)

11.2

Sept. 16

17.4 (17.0-18.2)

3.3 (3.0-4.8)

11.4

Empire

Empire was sampled for the second week. Like Jonathan, this variety is generally utilized as taffy apples and fresh apple slices. The target starch test for mature apples for apples destined for fresh market or fresh apple slices is 3.5 with a minimum firmness of 18 for long-term CA storage. Predicted harvest dates for fresh market for central Berrien County is Sept. 26, which seems to be about on target with the current average firmness of 18.6 and starch average of 2.9.

Empire maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 10

19.4 (18.0-20.0)

2.2 (2.2-2.5)

11.2

Sept. 16

18.6 (17.2-20.0)

2.9 (2.0-4.0)

11.3

Jonagold 

Jonagold was sampled for the second time. Starch conversion this week is averaging 3.8, with 3.5 as the target for mature for this variety. Fruit firmness this week averaged 17.7 pounds with the general guideline of a minimum of 17 pounds firmness for best long-term CA storage. The predicted peak harvest date is Sept. 30 for central Berrien County. This variety seems to be maturing slightly ahead of the predicted date.

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

Golden Delicious 

Golden Delicious was sampled for the first time this week. Starch conversion this week is averaging 1.6, with 3 as the target for mature for this variety. Fruit firmness this week averaged 17.5 pounds, pretty close to the general guideline of a minimum of 17 pounds firmness for best long-term CA storage. The predicted peak harvest date is Oct. 1 for central Berrien County. Starch conversion is lagging behind fruit softening this year.

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

 

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

*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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