Northwest Michigan apple maturity report – Sept. 25, 2019

Honeycrisp harvest is underway, and most growers are spot picking this variety.

General apple harvest comments

Most early varieties are finished up in the region. Ginger Gold, Zestar and SweeTango harvest is finished but these varieties are available in stores and farm markets/stands. Growers are ready to move into the mid-season varieties, and harvest has started based on color. Overall color is good across the region, and firmness is holding well. Brix continues to increase, and starch index are really beginning to drop. We have seen some variability in ripeness in our 10-apple samples this week, and growers will need to monitor their blocks to know when to initiate harvest. Apples are eating very well; they are juicy and flavorful. Consumers will be excited to eat Michigan fruit this season.

The weather forecast is not looking conducive for harvest. We are expected to have some sunny days, but for the most part the forecast is calling for rain for much of the next week. This weather pattern is coming at a bad time as growers are ready to really jump into the full-harvest swing.

Honeycrisp harvest really began in earnest late last week and into this week. Many growers are spot picking this variety as there is some variability on color within the tree canopy. As mentioned last week, many growers have invested in reflective fabric, and some growers have been summer pruning to improve color. Honeycrisp is well ahead of most Gala and McIntosh blocks. There is variability in Gala between blocks, which is likely due to strain and/or pruning strategies. Gala at the station are ready for harvest, and we have Buckeye Gala; we also thinned trees pretty effectively so there is excellent size and color. McIntosh seems slow to ripen this season despite good color, even on older strains. McIntosh is ripening but still eats pretty green.

Pest pressure continues to be low. We have not caught any brown marmorated stink bugs in our traps, and we have not observed any injury.

Apple maturity in northwest Michigan for apples collected on Sept. 25, 2019

Variety

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Honeycrisp

71.5 (56 - 89)

17.1 (16.9 – 17.7)

3.7 (2.1 – 4.8)

13.1 (12.2 – 14.5)

Gala

79.3 (65 - 100)

21.2 (20.2 – 21.9)

1.7 (1.1 – 3.2)

12.5 (11 - 14.5)

McIntosh

77.0 (66 - 88)

16.7 (15.3 – 18.1)

3.5 (3.0 – 3.9)

11.7 (11.4 - 11.9)

Individual variety results

Honeycrisp

Honeycrisp harvest has begun, and spot picking is underway on most farms across the region. Honeycrisp has been at markets and at farm stands for the past few weeks, but data indicate that this variety is really just entering the ripeness zone. Firmness has dropped but still quite good in our samples. Color continues to improve but not a huge jump from last week. Starch also has not changed from last week, but we are observing variability in color within our samples from individual farms.

This variety seems to be moving along quickly, and growers really need to be out testing and sampling to make sure they are not going to miss the peak window for harvest. Spot picking is the way to go with the variability in color.

Honeycrisp maturity sampling for the harvest season

Sample date

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 4

50.5 (44.5 - 56.5)

19.6 (19.2-20.0)

1.0 (1.0 - 1.0)

10.8 (10.4 - 11.2)

Sept. 10

53.9 (40.0 - 95.0)

18.6 (17.0 - 21.0)

1.4 (1.0 - 3.0)

11.5 (10.0 - 13.0)

Sept. 17

70.1 (57.5 - 78.5)

18.2 (16.5 - 18.7)

3.4 (1.8 - 4.9)

13.1 (12.2 - 15.2)

Sept. 25

71.5 (56.0 – 89.0)

17.1 (16.9 – 17.7)

3.7 (2.1 – 4.8)

13.1 (12.2 – 14.5)

Gala

Gala harvest seems to be all over the board this season. As mentioned above, our light crop of Buckeye Gala on young trees have excellent color and size, and starch removal are at 3.2. They are eating well and have lost that starchy flavor. However, other blocks of Gala that we tested are still well underripe and have poor color and have very low starch removal. These discrepancies could be due to rootstock, block, and strain. Gala harvest is still a ways off for most growers.

Gala maturity sampling for the harvest season

Sample date

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 10

64.0 (30.0 - 95.0)

22.3 (19.0 - 23.0)

1.0 (1.0 - 1.0)

9.8 (8.5 - 11.5)

Sept. 17

78.0 (54.0 - 95.0)

21.2 (16.8 - 23.0)

1.1 (1.0 - 1.7)

11.6 (10.0 - 14.5)

Sept. 25

79.3 (65 - 100)

21.2 (20.2 – 21.9)

1.7 (1.1 – 3.2)

12.5 (11 - 14.5)

McIntosh

McIntosh apples have been harder to find this season as some blocks have been removed. Color is improving, but the fruit still is eating green. This variety seems to be ripening slow this season, but starch removal is increasing. Brix really has not changed from last week, and firmness seems to be holding in this variety.

McIntosh maturity sampling for the harvest season

Sample date

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 10

74.3 (15.0 - 100)

16.1 (13.5 - 19.5)

1.7 (1.0 - 3.0)

10.6 (9.7 - 11.4)

Sept. 17

63.0 (29.5 - 92.5)

16.5 (15.0 - 18.2)

2.3 (2.2 - 2.4)

11.0 (10.9 - 11.1)

Sept. 25

77.0 (66.0 – 88.0)

16.7 (15.3 – 18.1)

3.5 (3.0 – 3.9)

11.7 (11.4 - 11.9)

 

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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