Grand Rapids area apple maturity report – Sept. 25, 2019

First harvest of early blocks of Honeycrisp and Gala will begin soon.

Gala apples
Photo by Nick Schweitzer of Schweitzer Orchards in Sparta, Michigan.

General comments

More rainfall over the weekend slowed harvest only on the rainy days; orchards seem to be drying out quickly despite saturated soils. Over the past week, many Gala blocks have been stripped and quite a few Honeycrisp have had their first picking. Many McIntosh blocks are harvested as well. In general, internal ethylene levels continue to be on the low side for many varieties, apart from Honeycrisp with is a high ethylene producing variety. Fruit firmness continues to be on the higher side of normal still. Fruit color is outstanding. In general, disorders such as bitter pit and water core have been not as prevalent this season, even with the heavy rainfall that sometimes exacerbates these physiological disorders.

In the Grand Rapids, Michigan, area, apple maturity seems to be coming in about four to five days ahead of our 2019 predicted apple harvest dates. Keep in mind these predicted dates are for peak harvest, so some fruits might be ready ahead or behind these dates as we move through maturity.

Brown marmorated stink bug and other stink bugs continue to be active with higher numbers in traps over the past week. Very little damage has been reported in apples at this time, other than in the areas with known high pressure over the past few years. Scouting of borders, especially near wooded areas, with lured traps is suggested. Orchards near soybean fields can sometimes be at a higher risk as beans begin to dry down and brown marmorated stink bugs move out to look for other food sources.

Continued heavy rainfall will keep fungi active in orchards. With the very heavy rain, the risk is not in stretching a fungicide spray, it’s that there is no fungicide left. Apple scab is still very much still present and will fruits will become susceptible as they near maturity, leading to pinpoint scab. The only way to prevent scab now is to make a fungicide application to prevent it from getting established on fruits. The abundant rainfall could increase pressure for the summer diseases of sooty blotch and fly speck. The risk for fruit rots is also increased with poor fungicide coverage and several wetting events. A good pre-harvest fungicide application can take care of a lot of future problems.

Variety sampling results

Strains are noted where applicable. We try our best to collect samples from blocks untreated with harvest management products. Samples collected for this report are from the general Grand Rapids area, targeting fruit that seems mature and on the outside of the tree and ready for the next picking.

Apple maturity summary in Grand Rapids area for fruit harvested Sept. 24, 2019

Variety

Firmness lbs (range)

Starch (range)

Brix% (range)

Gala

19.1 (14-24)

5.2 (1-8)

15.6 (13.5-17.5)

Honeycrisp

17.4 (14.5-21.5)

6.9 (4-8)

15.2 (13-17)

Empire

19.8 (18-22.5)

2.4 (2-3)

13.7 (13-14)

Jonagold

17.8 (15-22)

4.1 (2-7)

13.6 (13-14.5)

Golden Delicious

16.4 (14-22)

5.5 (4-7)

13.1 (12.5-14)

Red Delicious

18 (16-20.5)

2.2 (2-3)

12.2 (11.5-13)

Ida Red

24.6 (22.5-29.5)

2.7 (2-3)

13.3 (13-14.5)

Law Rome

20.5 (16.5-25.5)

1.5 (1-2)

12.2 (12-12.5)

Individual variety results

Gala

Quite a few Gala were harvested in the last week with many blocks being stripped in one picking. Fruit size is good to excellent. Internal ethylene is about the same as last week with 90% of fruits over the 0.2 ppm climacteric. Red color is excellent. Background color are all yellow. Fruit firmness is still excellent at 19.1 pounds. Starch clearing made a big jump forward in maturity from 2.8 last week to 5.2 this week. Brix are improved from 13 last week to 15.6 this week. Fruit sampled this week indicate Gala is moving quickly out of the long-term controlled atmosphere (CA) window into the mid-term CA condition where not treated with harvest management applications.

Traditional Gala (Gale, Buckeye) 2019 maturity sampling records, n=30

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch range)

Brix (range)

Aug. 21

NA

NA

49.3 (35-70)

4.8 (3-5)

23.7

1.8 (1-5)

10.8 (10-13.8)

Sept. 3

NA

NA

68.3 (45-90)

3.8 (3-5)

25.6

1.4 (1-3)

11.5 (10.4-12.8)

Sept. 10

0.8690

20

75.7 (50-90)

1

23.4 (21.5-26)

1.7 (1-7)

12 (11.5-12.5)

Sept. 17

1.0630

85

90.4 (40-100)

1

21.5 (14.6-24)

2.8 (1-7)

13 (11.8-14.5)

Sept. 24

1.8795

90

92 (30-100)

1

19.1 (14-24)

5.2 (1-8)

15.6 (13.5-17.5)

McIntosh

McIntosh harvest is going on right now. The block we collect fruit from has been harvested, so no additional data for this variety. Macs will move out of the long-term CA storage window by the end of this week. Hopefully the windy conditions for today won’t knock too many off.

September Wonder Fuji

The block we collect September Wonder Fuji in has been harvested, as have many early Fuji blocks. This variety is in its best form right now for direct fresh sales.

Honeycrisp

Honeycrisp harvest is well underway with excellent fruit color and quality being reported. Levels of bitter pit are lower than expected even in blocks with a light crop load. Some drop is occurring. Our predicted date for traditional Honeycrisp was Sept. 23 for peak harvest and it seemed to come in just a few days ahead of that date in the Grand Rapids area. Firmness is excellent at 17.4 pounds on average. The starch levels are the same as last week at 6.9 on average. Brix levels have really jumped from 14 last week to 15.2 this week.

Honeycrisp (Firestorm & original) 2019 maturity sampling records, n=60

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch (range)

Brix (range)

Aug. 28

NA

NA

26 (5-80)

4.7 (3-5)

18

1.7 (1-7)

12.8 (12.2-14.2)

Sept. 10

12.553

100

77 (50-90)

1.9 (1-3)

19.5 (16-28.5)

5 (1-8)

13.4 (12-14.3)

Sept. 17

16.639

95

68 (30-100)

1.7 (1-2)

15.7 (12.4-20.8)

6.9 (3-8)

13.98 (12-16)

Sept. 24

41.4024

97

87 (60-100)

1.3 (1-2)

17.4 (14.5-21.5)

6.9 (4-8)

15.2 (13-17)

Empire

Our predicted harvest date for Empire is Sept. 30, which seems to be a pretty good target—perhaps they will come in a bit ahead of that date for long-term CA or processor needs. Internal ethylene is just showing in a few apples this week, with no fruits over the 0.2 ppm climacteric. Fruit pressure is still excellent with similar averages and range of data points as last week.

Starch levels are holding in the 2 to 3 range, very similar to last week. Brix is very good at 13.7, up from 11.8 last week. The target starch test for mature Empire for fresh market sales or fresh slices is 3.5 with a minimum firmness of 18 for long-term CA storage. Empire will continue to improve over the next week, but you could start to think about harvest if color and market is right. I learned that the block we are sampling from has been treated with ReTain, which is so common in Empire.

Empire 2019 maturity sampling records, n=10

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch (range)

Brix (range)

Sept. 10

0

0

50 (25-60)

2.2 (2-3)

23.1 (21-25)

1.8 (1-2)

11.3 (10.8-11.8)

Sept. 17

0

0

48.5 (20-80)

2

19.5 (18-22.5)

2.5 (2-3)

11.8 (11-12.2)

Sept. 24

0.0300

0

72 (50-90)

2.4 (2-3)

19.8 (18-22.5)

2.4 (2-3)

13.7 (13-14)

Jonathan and Jonagold

The Jonathan block we were sampling from was harvested. We had one Jonagold sample and data indicate Jonagold are now entering the window for long-term CA storage where suggested parameters are 17 pounds pressure and 3.5 for starch clearing. The predicted harvest date for both Jonagold is Oct. 6, which seems to be about four to six days too late. Keep a close eye on your Jonagold blocks and harvest at the time that best fits your market for this variety. We think earlier will be better than later to get Jonagold in the bin. Perhaps the lighter crop load is at play.

Jonagold 2019 maturity sampling records, n=10

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch (range)

Brix (range)

Sept. 10

0.0181

0

32 (10-70)

3

22.1 (20-24)

1.7 (1-2)

12.6 (12-13)

Sept. 17

0.0320

0

22 (5-40)

2

18.7 (16.5-20.5)

2.8 (1-6)

12.8 (12-14)

Sept. 24

0.0240

0

37 (10-70)

2

17.8 (15-22)

4.1 (2-7)

13.6 (13-14.5)

Golden Delicious

The predicted harvest date for the Grand Rapids area for Golden Delicious is Oct. 8 and like Jonagold, this date might be five or more days too late for long-term CA storage. In general, Golden Delicious have a lighter than average crop load, which might be moving the maturity faster than predicted. This week’s Golden Delicious samples show 20% of fruits with internal ethylene now over the 0.2 ppm level.

Fruit firmness is a bit lower than we would really like to see at 16.4 pounds—very similar to last week. Starch clearing is up from 3.1 last week to 5.5 on average this week. Brix are improving. Keep a close eye on Golden Delicious, especially fruit pressure and starch levels. This variety is behaving strangely this season and could move through maturity quickly.

Golden Delicious 2019 maturity sampling records, n=10

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch (range)

Brix (range)

Sept. 10

0.0021

0

11.3 (5-15)

3

21.9 (19.5-24)

1

11.5 (11-12)

Sept. 17

0.0254

0

1.2 (0-5)

3

16.5 (14.6-18.6)

3.1 (1-5)

12.7 (12-13.8)

Sept. 24

0.0700

20

0

2.1 (2-3)

16.4 (14-22)

5.5 (4-7)

13.1 (12.5-14)

Red Delicious

This is our second week to look at Red Delicious. Fruits are still immature and have made slight improvements in maturity parameters. Our predicted harvest date is Oct. 11 and another week of sampling will tell us if that needs to be adjusted as we’ve had to do with other varieties. Internal ethylene numbers are still very low with no fruits over the 0.2 ppm climacteric. Red Delicious is a very low ethylene producing variety. Red color is improved from 61% color to 86% this week. Fruit firmness is still very good at 18 pounds on average. Starch clearing moved from 1.5 last week to 2.2 this week. Brix are improved from 11.2 last week to 12.2 this week.

Red Delicious 2019 maturity sampling records, n=10

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch (range)

Brix (range)

Sept. 17

0.0358

0

61.5 (30-85)

1.7 (1-2)

19.3 (16.4-21.8)

1.5 (1-2)

11.2 (11-12)

Sept. 24

0.0500

0

86.5 (70-95)

1.2 (1-2)

18 (16-20.5)

2.2 (2-3)

12.2 (11.5-13)

Ida Red

This is the first week for Ida Red samples. Our predicted harvest date is Oct. 15. These early results indicate immature fruits with numbers a bit higher in all parameters than expected. Next week will really tell us what’s going to happen with Ida Red and if they will be ahead of our precited harvest dates as well.

Ida Red 2019 maturity sampling records, n=10

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch (range)

Brix (range)

Sept. 24

0.0260

0

71 (60-90)

2

24.6 (22.5-29.5)

2.7 (2-3)

13.3 (13-14.5)

Rome

This was our first week to take a Rome sample. We are using Law Rome. Our predicted harvest date is Oct. 20. Like the Ida Red, this first sample is a bit farther ahead in maturity than expected and next week will be helpful to better understand.

Law Rome 2019 maturity sampling records, n=10

Date of sample

Avg. Ethylene (ppm)

% Fruits with Ethylene over 0.2 ppm

Red color % (range)

Background color (range)

Avg Firmness lbs pressure (range)

Starch (range)

Brix (range)

Sept. 24

0.0228

0

24.5 (10-60)

2.9 (2-3)

20.5 (16.5-25.5)

1.5 (1-2)

12.2 (12-12.5)

Apple maturity sampling parameters

  • % fruits with internal ethylene over 0.2 ppm = indicates when ethylene begins to influence fruit ripening and it cannot be held back easily after this is reached.
  • 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.
  • Starch: 1 = all starch, 8 = No starch; range is of all fruits tested. Using Cornell Starch Iodine Index Chart.

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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