West central Michigan apple maturity report – Aug. 18, 2017

Current forecasts indicate we are three to eight days ahead of normal harvest dates, depending on cultivar.

Predicted harvest dates are now available on the Michigan State University Enviroweather website for the west central region. However, accurately predicting harvest with these models may be a challenge this season. Cool weather early in the spring resulted in an extended period of bloom, and the May frost events killed early blooms at many sites. The frost events also caused an atypical fruit set on one- and two-year-old wood, which will result in mixed maturity within some orchards.

Growers were extremely cautious with thinners following the frost, and this has resulted in further variability in crop set. In spite of frost, some blocks are actually carrying a heavier than desired crop load because of hesitation with thinners this spring. Other blocks are so light that growers are weighing the economic benefit of harvesting them at all.

Our current forecast indicates we are between three and eight days ahead of normal harvest dates, depending on cultivar. However, you will have to consider the crop load in a block when determining harvest. Blocks with a light crop could mature three to four days before our predicted harvest dates. Conversely, blocks with a heavy crop load could mature several days late.

Normal harvest dates for our region are listed below for McIntosh, Jonathan and Red Delicious based on previous data compiled by MSU Extension educators Phil Schwallier and Amy Irish-Brown. I am also including normal harvest dates for the Ridge they have compiled over the years, as we can expect to track anywhere from three to seven days later, depending on cultivar.

Predicted harvest dates for Hart, Michigan

Cultivar

Predicted harvest date

Days ahead of normal

Days ahead of last year

McIntosh

Sept. 13

5

0

Jonathan

Sept. 30

3

2

Red Delicious

Oct. 6

8

2

 

Predicted harvest dates for the Ridge

Variety

Normal date

2017 predicted date

Paulared

Aug. 24

Aug. 19

Gingergold

Aug. 26

Aug. 21

Gala

Sept. 10

Sept. 5

McIntosh

Sept. 15

Sept. 5

Honeycrisp

Sept. 18

Sept. 15

Empire

Sept. 26

Sept. 25

Jonathan

Sept. 28

Sept. 27

Jonagold

Sept. 28

Sept. 27

Golden Delicious

Oct. 2

Oct. 1

Red Delicious

Oct. 5

Oct. 4

Idared

Oct. 10

Oct. 9

Rome

Oct. 15

Oct. 14

Fuji

Oct. 25

Oct. 24

Braeburn

Oct. 25

Oct. 24

Goldrush

Nov. 1

Oct. 31

Apple maturity sampling parameters

  • Color % = the visual percentage of red color from 0 to 100; range is of all fruits tested.
  • Background color: 5 = Green, 1 = Yellow; range is of all fruits tested.
  • Firmness in pounds
  • Starch: 1 = all starch, 8 = No starch; range is of all fruits tested.
  • Brix = % sugar

Variety sampling results

Honeycrisp are beginning to size and color, but are still several weeks from maturity. Fruits sampled from Oceana and Mason counties are similar in maturity progression. As always, growers closer to the lake in both counties lag behind in development. If you are planning to use ReTain this season, apply it 30 days pre-harvest.

Honeycrisp variety results

Sampling date

Color (% red) Avg. (range)

Background color

Avg. (range)

Firmness Avg. (range)

Starch

Brix Avg. (range)

Aug. 16

17 (5-40)

3.84 (3-5)

20.13 (17.5-22.5)

1

10.16 (9-12)

Gala crop load is generally heavier than expected at many sites, leading to smaller fruit size. The high variability in color has to do with differences in cultivar and crop load across sampled blocks. Lighter crops of redder strains of Gala are well-colored already, while heavier crops of older strains are less so. However, range of starch index, firmness and brix was more consistent across sampled sites.

Gala variety results

Sampling date

Color (% red)

Background color

Firmness

Starch

Brix

Aug. 16

32.75 (5-80)

3.5 (1-4)

24.19 (21-30)

1.1 (1-2)

10.30 (9.5-11.5)

McIntosh are furthest along in development, as we would expect. Starch index measurements are creeping further ahead than other cultivars, but harvest is still at least a couple of weeks away even at the earliest sites.

McIntosh variety samples

Sampling date

Color (% red)

Background color

Firmness

Starch

Brix

Aug. 16

17.5

3.95 (3-4)

17.51 (15-26.5)

2.95 (2-4)

11.12 (10.5-12.5)

As we approach harvest, start to consider the suggested parameters for long-term storage for all of the cultivars at your operation. Below are the suggested firmness and starch index levels for longer and shorter term controlled atmosphere (CA) storage by variety.

Suggested firmness and starch index levels for long-term and shorter-term CA storage by variety

Variety

Firmness (pounds)

Starch index

Short CA

Mid-CA

Long CA

Mature

Over mature

McInotsh

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

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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