East Michigan apple maturity report – Oct. 16, 2019

Growers are harvesting a few Red Delicious strains, but there are several other varieties that have jumped ahead of Red Delicious in terms of maturity.

General apple harvest comments

Most apple growers are closing in on the end of apple harvest, some expected to finish by the end of next week. Most growers have finished harvesting Golden Delicious and have started harvesting some strains of Red Delicious, Idared at some farms, Northern Spy and a few Crispin blocks on early maturing sites. Romes are also ready to begin harvest. In testing done this week, Fuji harvest can also get underway.

EverCrisp need to hang longer to help improve fruit size, color and for a better background color. Cameo are close to being ready to harvest. On the list of varieties that need more time to mature are Braeburn, Winesap and Enterprise.

The seventh apple harvest report for the 2019 apple harvest season follows with more details on the 11 varieties tested this week, two of which are new varieties being tested, Winesap and Enterprise.

Our predicated apple harvest dates for east Michigan are three to four days later than the normal dates. Here is the link for the 2019 apple predicted harvest dates article that was emailed to area growers as well as published on our Michigan State University Extension Fruit & Nuts News website in August.

Apple maturity in east Michigan for apples harvested Oct. 14

Variety

% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Red Delicious

64 (20-100)

100 (100-100)

17.7 (16.7-18.5)

2.8 (2.0-3.5)

13.3

Idared

70 (40-100)

96 (93-97)

18.1 (14.7-19.5)

3.1 (2.1-3.8)

14.1

Northern Spy

100 (100-100)

64 (48-80)

23.0 (22.6-23.3)

4.1 (2.7-5.5)

14.4

Crispin

40 (0-80)

14 (2-26)

20.4 (20.2-20.6)

2.9 (1.8-4.0)

13.9

Rome

20 (20-20)

98 (90-100)

22.0 (18.0-25.0)

3.8 (3.0-5.0)

13.6

EverCrisp

40 (0-80)

82 (69-95)

20.6 (19.7-21.4)

3.4 (3.4-3.4)

15.1

Fuji

33 (0-80)

83 (58-96)

20.6 (18.9-22.3)

4.7 (4.0-5.2)

14.7

Cameo

20 (0-40)

89 (80-98)

19.4 (19.3-19.5)

3.0 (2.2-3.8)

15.0

Braeburn

30 (20-40)

88 (79-97)

24.0 (23.7-24.2)

1.3 (1.0-1.6)

14.0

Winesap

30 (20-40)

93 (86-100)

21.8 (21.3-22.2)

1.5 (1.4-1.5)

13.4

Enterprise

40 (40-40)

93 (70-100)

20.0 (17.0-24.0)

2.9 (2.0-5.0)

15.1

Individual variety results

Red Delicious

Red Delicious was sampled for the fourth week of the season. Overall, Reds have been very slow to mature. There was a mix of Red strains tested this week, many were still Redchief strain where I could find them unharvested. Many early strains have been picked in the last week. Based on this week’s data, most strains of Red Delicious are ready to begin harvest for fruit that is intended for long-term storage. For more immediate fruit sales, many blocks of Reds need a few more days to develop better flavor. Many still have a woody taste.

The predicted harvest date for Red Delicious was Oct. 5, but it was not ready to be picked then. This week, 64% of fruit tested had internal ethylene levels over 0.2 parts per million (ppm) and the pressure is 17.7 pounds. The average starch index is up from 2.6 last week to 2.8 this week, but remember that the cross section of this sample is from later maturing strains. We usually look for a starch index for Red Delicious to be around 2.5 to 3.0 for fruit that is intended for long-term storage, but for fresh sales I look for the starch index to be closer to 3.5.

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. 23

10 (0-40)

93 (70-100)

18.6 (17.2-19.4)

2.1 (1.9-2.4)

11.8

Sept. 30

45 (0-100)

100 (100-100)

18.9 (16.3-19.9)

2.5 (2.0-3.0)

12.8

Oct. 7

33 (0-80)

100 (100-100)

18.0 (16.6-20.7)

2.6 (2.3-2.8)

12.5

Oct. 14

64 (20-100)

100 (100-100)

17.7 (16.7-18.5)

2.8 (2.0-3.5)

13.3

Idared

Idared was sampled for the fourth week of the season. Idared are close to being ready for harvest at most farms and at fewer farms the harvest window is just starting to open. We usually look for a starch index for Idared to be around 3.5. The predicted harvest date for Idared was Oct. 11 and it was not ready to begin harvest then.

This week, 70% of the fruit tested had internal ethylene levels over 0.2 ppm and the pressure remains firm at 18.1 pounds. The average starch index is up from 1.9 last week to 3.1 this week—this is a nice jump. Idared are ready before many Red Delicious strains.

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. 23

0 (0-40)

56 (48-65)

18.8 (17.9-20.1)

1.6 (1.5-1.9)

13.2

Sept. 30

25 (0-40)

84 (75-91)

19.0 (17.9-20.4)

1.9 (1.6-2.2)

13.3

Oct. 7

60 (40-80)

88 (80-89)

16.6 (15.5-18.2)

1.9 (1.4-2.3)

13.8

Oct. 14

70 (40-100)

96 (93-97)

18.1 (14.7-19.5)

3.1 (2.1-3.8)

14.1

Northern Spy

Northern Spy was sampled for the fourth week of the season, with fewer blocks tested this week because many blocks have been harvested in the last few days. Based on this weeks’ data, Northern Spy are ready to begin harvest. The predicted harvest date for Northern Spy was Oct. 12, I believe most were mature close to this date.

All the fruit tested this week had internal ethylene levels over 0.2 ppm, Northern Spy are high ethylene producers, and the pressure is still firm at 23.0 pounds. The average starch index is up from 2.8 last week to 4.1 this week, a nice jump over one week. Spy’s are also ahead of Red Delicious.

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. 23

40 (0-80)

31 (30-32)

22.2 (20.3-24.1)

1.4 (1.0-1.8)

12.7

Sept. 30

35 (20-60)

30 (3-46)

21.6 (19.3-23.9)

1.9 (1.4-2.1)

12.7

Oct. 7

90 (60-100)

34 (34-34)

19.6 (18.8-21.6)

2.8 (1.8-3.3)

13.3

Oct. 14

100 (100-100)

64 (48-80)

23.0 (22.6-23.3)

4.1 (2.7-5.5)

14.4

Crispin

Crispin or Mutsu was sampled for the fourth week of the season. Based on this week’s data, some blocks of Crispin are ready to begin harvest while others are not ready. The predicted harvest date for Crispin was Oct. 13, some blocks were mature close to this date.

This week, 40% of fruit tested had internal ethylene levels over 0.2 ppm and the pressure is unchanged at 20.4 pounds. The average starch index is up from 1.6 last week to 2.9 this week. I did not find additional blister spot symptoms this week as I have seen the previous two weeks.

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. 23

20 (0-40)

3 (1-5)

21.0 (20.3-21.6)

2.1 (2.0-2.1)

12.5

Sept. 30

0 (0-0)

11 (2-22)

21.5 (20.3-23.7)

1.9 (1.0-2.6)

13.4

Oct. 7

0 (0-0)

10 (7-13)

20.4 (19.7-21.0)

1.6 (1.0-2.1)

13.6

Oct. 14

40 (0-80)

14 (2-26)

20.4 (20.2-20.6)

2.9 (1.8-4.0)

13.9

Rome

Rome was sampled for the second week of the season, with the number of blocks tested decreased as many blocks have been harvested in the last week. Most Rome blocks were ready to begin harvest last week and the remaining blocks are now ready to be harvested. The predicted harvest date for Rome was Oct. 15.

This week, 20% of fruit tested had internal ethylene levels over 0.2 ppm and the pressure is still very firm at 22 pounds. The average starch index is 3.8 this week. Rome maturity is also ahead of Red Delicious.

Rome 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. 30

0 (0-0)

82 (60-100)

23.9 (21.5-26.0)

3.1 (3.0-4.0)

13.7

Oct. 7

20 (0-40)

87 (81-92)

22.5 (21.1-22.9)

3.4 (3.1-3.6)

13.3

Oct. 14

20 (20-20)

98 (90-100)

22.0 (18.0-25.0)

3.8 (3.0-5.0)

13.6

EverCrisp

EverCrisp was sampled for the third week of the season. Looking at this week’s data and based on the starch index of 3.8, EverCrisp are ready to begin harvest. However, harvest can be delayed to wait for better size, brix and skin color. This variety is known for high brix levels, currently testing 15.1%. They still eat on the green side and are rock hard. The predicted harvest date for EverCrisp is Oct. 23, or about 15 days after the predicted harvest date for Red Delicious. Remember that this variety is so new that we don’t have a long track record of predicting its maturity.

This week, 40% of fruit tested had internal ethylene levels over 0.2 ppm. The pressure is still very firm at 20.6 pounds, well above the minimum of 18 pounds for best long-term CA storage. The average starch index has moved from 3.2 last week to 3.4 this week. A minimum of 3.0 for the starch index is recommended for harvesting for fresh sales of EverCrisp. Changing of background color from green to a lighter green or slight yellow appears to be a good indicator of a mature apple.

EverCrisp 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. 30

20 (0-40)

70 (54-85)

22.8 (20.4-23.1)

1.9 (1.5-2.3)

14.5

Oct. 7

70 (60-80)

 

20.8 (20.1-21.4)

3.2 (2.4-3.9)

14.5

Oct. 14

40 (0-80)

82 (69-95)

20.6 (19.7-21.4)

3.4 (3.4-3.4)

15.1

Fuji

Fuji was sampled for the fourth week of the season and are ready to begin harvest. The predicted harvest date for Fuji is Oct. 23, but they are mature well ahead of this date. This week, 33% of the fruit tested had internal ethylene levels over 0.2 ppm and the pressure is still very firm at 20.6.

When I picked Fuji on Monday, the color looked like it had improved compared to last week, but the data doesn’t reflect my observation. The average starch index has jumped from 2.8 last week to 4.7 this week. Fuji maturity is well ahead of Red Delicious.

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 %

Sept. 23

0 (0-0)

29 (20-40)

20.1 (17.5-23.0)

1.9 (1.0-2.0)

13.1

Sept. 30

7 (0-20)

69 (43-85)

22.2 (20.8-23.3)

2.1 (1.8-2.5)

13.9

Oct. 7

27 (0-60)

92 (75-100)

20.3 (18.2-22.2)

2.8 (2.5-3.0)

14.0

Oct. 14

33 (0-80)

83 (58-96)

20.6 (18.9-22.3)

4.7 (4.0-5.2)

14.7

Cameo

Cameo was sampled for the third week of the season. Based on this week’s data, Cameo are close to begin harvest, but need a few more days to mature. I believe they will be ready late this week to early next week. I don’t have Cameo on the predicted harvest dates list in the table that follows, but I believe it matures between Rome and Fuji, or around Oct. 20. It will be mature close to this date.

This week, 20% of fruit tested had internal ethylene levels over 0.2 ppm and the pressure is unchanged at 19.4 pounds. The average starch index has moved from 2.5 last week to 3.0 this week.

Cameo 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. 30

10 (0-20)

94 (92-95)

20.0 (18.9-21.1)

1.9 (1.8-2.5)

13.8

Oct. 7

0 (0-0)

90 (50-100)

19.4 (19.1-19.6)

2.5 (2.0-3.0)

13.9

Oct. 14

20 (0-40)

89 (80-98)

19.4 (19.3-19.5)

3.0 (2.2-3.8)

15.0

Braeburn

Braeburn was sampled for the second week of the season. Based on this week’s data, Braeburn are not ready to begin harvest. The predicted harvest date for Braeburn is Oct. 28. Last week I said it would be mature before this date, but looking at this week’s data, that date may be close to accurate.

This week, 30% of fruit tested had internal ethylene levels over 0.2 ppm and the pressure is still rock hard at 24.0 pounds. The average starch index is still only at 1.3 this week.

Braeburn 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. 7

20 (0-40)

 

23.9 (23.2-24.5)

1.3 (1.2-1.4)

12.7

Oct. 14

30 (20-40)

88 (79-97)

24.0 (23.7-24.2)

1.3 (1.0-1.6)

14.0

Winesap

Winesap was sampled for the first week of the season to get an early read on its maturity. Based on one week’s worth of data, Winesap are not ready to begin harvest. The predicted harvest date for Winesap is Oct. 30, but I believe it will be mature before this date.

This week, 30% of fruit tested had internal ethylene levels over 0.2 ppm and the pressure is firm at 21.8 pounds. The average starch index is only 1.5 this week.

Winesap 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. 14

30 (20-40)

93 (86-100)

21.8 (21.3-22.2)

1.5 (1.4-1.5)

13.4

Enterprise

Enterprise was sampled for the first week of the season to get an early read on its maturity. Based on one week’s worth of data, Enterprise are close but not ready to begin harvest. I do not have a predicted harvest date for Enterprise on the last table at the end of this article, but it is very close to the predicted harvest date for Winesap, which is Oct. 30.

This week, 40% of fruit tested had internal ethylene levels over 0.2 ppm and the pressure firm at 20.0 pounds. The average starch index is 2.9 this week.

Enterprise 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. 14

40 (40-40)

93 (70-100)

20.0 (17.0-24.0)

2.9 (2.0-5.0)

15.1

Predicted peak fresh market apple harvest dates for east Michigan

Each year we publish predicted harvest dates for many locations across the state. These predicted harvest dates are based on a long-established formula using the bloom date and temperatures for 30 days post-bloom.

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. Keep a close eye on these weekly Apple Harvest Updates for possible revisions of these dates.


Normal and 2019 peak harvest dates for apple varieties for east Michigan

Variety

Normal date

2019 predicted date

Paula Red

8/22

8/25

Zestar

8/22

8/22

Gingergold

8/23

9/26

Gala

9/8

9/11

McIntosh

9/13

9/16

Early Fiji

9/14

9/17

Honeycrisp

9/16

9/20

Empire

9/20

9/24

Jonathan

9/23

9/27

Jonagold

9/23

9/27

Cortland

9/25

9/29

Golden Delicious

9/29

10/3

Red Delicious

10/1

10/5

CandyCrisp

10/5

10/10

Idared

10/6

10/11

Northern Spy

10/8

10/12

Crispin (Mutsu)

10/9

10/13

Rome

10/11

10/15

Autumn Gala

10/17

10/21

EverCrisp

10/19

10/23

Fuji

10/22

10/26

Braeburn

10/23

10/28

Winesap

10/26

10/30

Goldrush

10/31

11/4

*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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