East Michigan apple maturity report – Oct. 3, 2018

Growers are approaching the midpoint in apple harvest. Some varieties are picking out shorter than expected, due mainly to smaller fruit size that is the result of prolonged drought earlier this summer.

General apple harvest comments

The order of apple varieties ready to harvest is a bit of a moving target this season and is much different than our typical order. Apple varieties seem to be falling into two categories this harvest season: those that are maturing quickly and are ready to harvest ahead of schedule and those that are slowly and steadily moving toward maturity. The list of those slow and steady maturing varieties this week is the shorter of the two lists, including Empire, Cortland, Idared and Crispin. The rest of our varieties fall into the other quick to mature or maturing early list.

Most apple growers are about midway in their apple harvest. This week, growers are finishing harvest of Jonagold, are working away at Golden Delicious and at some farms early maturing strains of Red Delicious. Varieties that are nearing ready to harvest or are ready now include Empire, Cortland and at some farms even Northern Spy. Also, some Fuji blocks are ready for a good first picking. Idared and Crispin are not ready to harvest. More details on the maturity of each of these varieties follows.

This was the fifth week of our harvest season to collect apple samples on Monday from a number of orchards in east Michigan and have them analyzed Tuesday at the Department of Horticulture Post Harvest Lab at Michigan State University. I tabulated the results last night and early this morning to produce this report. The number of varieties tested this week dropped back from 10 last week to 9 this week. The list of varieties tested this week includes Empire, Jonagold, Cortland, Golden Delicious, Red Delicious, Idared, Northern Spy, Crispin and this week I added Fuji.

Growers are reporting that some varieties picked out short, mostly caused from the drought conditions that started in early to mid-June at most farms. Except on farms that are utilizing H2A workers, harvest labor is still short at most farms. Some growers are falling behind with harvest. Rains of the last week also slowed apple harvest.

Brown marmorated stink bug (BMSB) monitored trapping locations are still catching close to 50 BMSB at about a third of the orchards in east Michigan. Some growers have applied insecticides to control them. Even more sooty blotch and flyspeck, woolly apple aphid and San Jose scale are being found at many farms. A number of blocks are also seeing lenticel rot and black rot symptoms.

Here is the link for the 2018 Predicted Harvest Dates article that was posted to the MSU Extension in July. A list of predicated harvest dates for east Michigan is listed at the end of this article as well. Spend time in your orchard every few days to evaluate the maturity of your apple varieties.

Apple maturity in east Michigan for apples harvested Oct. 1

Variety

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Empire

5 (0-10)

83 (79-86)

16.1 (16.0-16.1)

3.5 (3.4-3.5)

13.8

Jonagold

40 (40-40)

74 (50-85)

15.9 (14.5-19.5)

5.1 (5.0-6.0)

15.0

Cortland

97 (90-100)

86 (73-96)

14.3 (14.2-14.4)

3.6 (3.2-4.5)

13.2

Golden Delicious

0 (0-0)

19 (10-27)

15.2 (14.6-15.7)

5.3 (4.5-6.0)

13.9

Red Delicious

33 (0-50)

93 (89-96)

15.9 (15.7-16.0)

2.9 (2.1-4.4)

12.2

Idared

37 (10-60)

84 (71-93)

15.2 (13.1-17.7)

2.1 (1.5-3.3)

12.6

Northern Spy

78 (40-100)

76 (63-99)

18.5 (16.6-20.0)

3.8 (2.3-4.3)

13.5

Crispin

15 (0-40)

16 (5-26)

17.2 (16.3-19.1)

2.4 (1.2-4.0)

12.5

Fuji

7 (0-20)

74 (53-93)

18.0 (17.1-18.9)

3.7 (2.5-5.1)

13.2

Individual variety results

Empire was sampled for the fourth week of the season. Empire has been on a short list of varieties that have been slowly and steadily moving toward maturity. Based on this week’s data, Empire are finally ready to begin harvest at this time. The predicted harvest date for Empire was Sept. 18, but here it is in early October and it is just now ready to harvest. The fruit color has improved to 83 percent, the pressure is still firm at 16.1 pounds and the average starch index is up from 3.0 last week to 3.5 this week.

Empire maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 10

8 (0-10)

67 (63-70)

18.9 (16.5-20.5)

1.7 (1.2-2.1)

11.3

Sept. 17

8 (0-20)

69 (60-75)

17.7 (16.6-18.9)

2.4 (1.6-3.3)

11.9

Sept. 24

10 (0-40)

78 (69-91)

16.2 (15.1-17.2)

3.0 (1.9-4.9)

12.5

Oct. 1

5 (0-10)

83 (79-86)

16.1 (16.0-16.1)

3.5 (3.4-3.5)

13.8

Jonagold was sampled for the third week of the season and this week the sampling was limited to only a few orchards, as many blocks have been harvested. So, this sample size is limited to later maturing sites. Jonagold was ready to harvest at most sites last week, and this week’s data confirms it was mature at most farms last week. Based on this week’s data, these later maturing sites are ready to harvest. The predicted harvest date for Jonagold was Sept. 21, but based on three weeks of data it appears it was ready to harvest earlier.

The fruit color has improved to 74 percent this week, with fruit firmness averaging 15.9 pounds and the starch index averaged 5.1. While it appears the starch index has dropped from 7.1 last week to 5.1 this week, this is a sampling issue, as most blocks have been harvested. Lastly, a few growers felt the Jonagold was still too green in color to harvest, so they questioned my conclusions on Jonagold maturity. Unfortunately, fruit color and maturity don’t always match up closely.

Jonagold maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

27 (0-50)

47 (33-59)

16.6 (15.3-18.4)

5.3 (4.1-6.2)

14.0

Sept 24

53 (48-60)

66 (47-73)

16.0 (15.5-16.6)

7.1 (6.3-7.8)

13.8

Oct. 1

40 (40-40)

74 (50-85)

15.9 (14.5-19.5)

5.1 (5.0-6.0)

15.0

Cortland was sampled for the fourth week of the season; most blocks tested this week were Redcort with a few regular Cortland blocks added in. Based on this week’s data, Cortland are finally ready to begin harvest. Cortland, along with McIntosh and Empire, were very slow to mature this season. The predicted harvest date for Cortland was Sept. 22, but they were not mature on this date.

Almost all fruit are producing internal ethylene levels greater than 0.2 parts per million (ppm), up from 33 percent last week to 97 percent this week. Fruit color has improved to 86 percent this week, the fruit firmness has dropped to an average of 14.3 pounds and the starch index has moved from 2.3 last week to 3.6 this week. There has been some fruit drop in Cortland over the last week, but most of this drop has been caused from fruit push off as it has sized.

Cortland maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 10

45 (0-90)

75 (68-81)

17.3 (16.1-18.5)

1.1 (1.0-1.1)

12.7

Sept. 17

25 (0-50)

71 (57-85)

16.6 (15.8-17.3)

2.6 (2.0-3.2)

13.5

Sept. 24

33 (30-40)

81 (73-91)

14.7 (14.1-15.2)

2.3 (1.7-2.2)

12.5

Oct. 1

97 (90-100)

86 (73-96)

14.3 (14.2-14.4)

3.6 (3.2-4.5)

13.2

Golden Delicious was sampled for the third week of the season. The number of samples taken this week dropped back as growers have been harvesting Goldens. Many Golden blocks were ready to begin harvest last week. Based on this week’s data, later maturing sites of Goldens are ready to begin harvest. The fruit color or blush has been slow to develop in Goldens this season, and in the last week color has improved from 9 percent last week to 19 percent this week.

Like Jonagold, some growers waited to begin harvest for better color on Goldens. They matured very close to the predicted harvest date of Sept. 23. The fruit firmness was 16.6 pounds last week, dropping to 15.2 pounds this week. The average starch index moved from 5.1 last week to 5.3 this week. They are eating much better this week.

Golden Delicious maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

5 (0-10)

0 (0-0)

17.0 (15.7-18.6)

3.6 (3.0-4.3)

13.4

Sept. 24

3 (0-10)

9 (5-21)

16.6 (16.1-17.1)

5.1 (4.7-5.8)

13.7

Oct. 1

0 (0-0)

19 (10-27)

15.2 (14.6-15.7)

5.3 (4.5-6.0)

13.9

Red Delicious was sampled for the third week of the season with increased sampling this week and I shifted the mixture of stains sampled to more of the center of the road maturing strains. Last week I stated that some early maturing Red Delicious strains and sites are ready to begin harvest, while most others need more time to mature. Based on this week’s data set, the more centered maturing strains of Red Delicious still need more time to mature. The predicted harvest date for Red Delicious was Sept. 29, so they are maturing after this date.

The fruit color remains very good at 93 percent, fruit firmness dropped slightly averaging 15.9 pounds and starch index dropped back from an average of 4.0 last week to an average of 2.9 this week. I think this starch index drop reflects the shift in strains sampled this week compared to last week. The decision to begin harvesting Red Delicious needs to be made on a block by block basis this season, as their maturity is all over the board and largely depends on the strain and site. Many blocks I have tasted this week are still eating green.

Red Delicious maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

30 (0-60)

99 (98-100)

17.2 (17.0-17.4)

3.7 (3.6-3.8)

11.4

Sept 24

23 (10-60)

93 (90-97)

16.0 (15.1-17.1)

4.0 (1.6-5.9)

11.4

Oct. 1

33 (0-50)

93 (89-96)

15.9 (15.7-16.0)

2.9 (2.1-4.4)

12.2

Idared was sampled for the second week of the harvest season. Based on this week’s data, Idared are not ready to begin harvest. The predicted harvest date for Idared is Oct. 4 or tomorrow; they will not be ready for harvest by this date. They can be added to the list of slow to mature varieties. The fruit color has improved averaging 84 percent, fruit firmness dropped to 15.2 pounds and the starch index is only at 2.1. They are eating very green.

Idared maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 24

48 (20-80)

73 (65-80)

16.4 (14.9-17.8)

1.8 (1.2-2.6)

12.6

Oct. 1

37 (10-60)

84 (71-93)

15.2 (13.1-17.7)

2.1 (1.5-3.3)

12.6

Northern Spy was sampled for the second week of the season. Based on this week’s data, many early blocks are ready to begin harvest, with some blocks needing a few more days to mature. The predicted harvest date for Northern Spy is Oct. 3, or today. I feel we are close to being right on top of this date. The fruit color has improved to 76 percent. The starch index averaged 3.4 last week and 3.8 this week; however, the range of starch index is quite broad or wide starting at 2.3 and extending to 4.3. Some blocks are eating fine, while many are still eating on the green side.

Northern Spy maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 24

80 (30-100)

62 (40-93)

18.0 (16.0-21.9)

3.4 (1.9-5.2)

12.7

Oct. 1

78 (40-100)

76 (63-99)

18.5 (16.6-20.0)

3.8 (2.3-4.3)

13.5

Crispin or Mutsu was sampled for the third week of the season. Based on this week’s data, only a few blocks of Crispin are ready to begin harvest, with most needing more time to mature and are not ready yet. The predicted harvest date for Crispin is Oct. 6. I don’t believe most blocks will be ready to begin harvest by this date.

The fruit color is better than last week, averaging 16 percent, with the average starch index still at 2.4. However, the range of starch index is quite broad, ranging from an average of 1.2 to 4.0. Fruit finish is excellent so far this season; I have seen only a trace of blister spot showing up in Crispin. Most blocks are still eating green.

Crispin maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

0 (0-0)

0 (0-0)

18.3 (16.0-20.5)

2.3 (1.0-4.0)

11.4

Sept. 24

8 (0-20)

8 (2-19)

17.9 (17.0-19.0)

2.4 (1.0-5.2)

12.0

Oct. 1

15 (0-40)

16 (5-26)

17.2 (16.3-19.1)

2.4 (1.2-4.0)

12.5

Fuji was sampled for the first week of the season to get an early read on its maturity. Based on only one week of data, Fuji are very close to being ready to begin harvest but most blocks need a few more days to mature. The predicted harvest date for Fuji is Oct. 18, and it appears from this week’s data it was ready to harvest earlier. The fruit color is good for Fuji averaging 74 percent, fruit firmness averaged 18.0 pounds and the starch index averaged a surprising 3.7, with a range of 2.5 to 5.1. So, a few Fuji blocks are ready to begin harvest, most needing a few more days to mature.

Fuji maturity sampling for the harvest season

Sample date

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 1

7 (0-20)

74 (53-93)

18.0 (17.1-18.9)

3.7 (2.5-5.1)

13.2

Predicted peak fresh market apple harvest dates for East Michigan

Each year we publish predicted harvest dates for three varieties for many locations across the state. This year's “Predicted 2018 apple harvest dates” were published July 10. These predicted harvest dates are based on a long-established formula using the bloom date and temperatures for 30 days post-bloom. The information in this article lists the bloom and harvest dates for Deerfield and Romeo, Michigan.

The following table has predicted apple harvest dates for east Michigan. It has been expanded to include more apple varieties and lists only one date for the entire east Michigan region, which is hard to do! You can adjust these predicted harvest dates based on your actual bloom dates or on the typical harvest dates at your farm.

These dates are an estimate and will be affected by the apple strain, rootstock, crop load, fertility, soil type, and other factors including weather this season. Due to the early start to our growing season and much above normal temperatures this summer, I believe our actual harvest dates may be a few days ahead of these predicted harvest dates for most varieties. Keep a close eye on the weekly apple harvest updates for possible revisions of these dates.

Normal and 2018 peak harvest dates for apple varieties in east Michigan

Variety

Normal date

2018 predicted date

Paula Red

8/22

8/17/18

Gingergold

8/23

8/20/18

Gala

9/8

9/5/18

McIntosh

9/13

9/7/18

Early Fuji

9/14

9/9/18

Honeycrisp

9/16

9/12/18

Empire

9/20

9/18/18

Jonathan

9/23

9/21/18

Jonagold

9/23

9/21/18

Cortland

9/25

9/22/18

Golden Delicious

9/29

9/23/18

Red Delicious

 

 

10/1

9/29/18

CandyCrisp

10/5

10/3/18

Ida Red

10/6

10/4/18

Northern Spy

10/8

10/3/18

Crispin

10/9

10/6/18

Rome

10/11

10/7/18

Autumn Gala

10/17

10/14/18

EverCrisp

10/19

10/17/18

Fuji

10/22

10/18/18

Braeburn

10/23

10/21/18

Winesap

10/26

10/24/18

Goldrush

10/31

10/29/18

 

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.


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