Grand Rapids area apple maturity report – Oct. 23, 2019

The 2019 apple harvest is winding down in the Grand Rapids area.

General comments

Apple harvest in the general Grand Rapids, Michigan, area is nearly complete. Some have already finished picking and some with significant acreage of late varieties tell us they will wrap by the end of this week or early next week. Most varieties in the Grand Rapids area continue to mature about four to five days or more ahead of our 2019 predicted apple harvest dates.

This will be the last apple maturity report for the 2019 growing season. If you have suggestions for us to consider, please let us know at irisha@msu.edu. Phil and I strive to make this report usable for producers.

Variety sampling results

Many of the blocks we were sampling from are now harvested with only five varieties sampled this week.

Apple maturity summary in Grand Rapids area for fruit harvested Oct. 21, 2019

Variety

Firmness lbs. (range)

Starch (range)

Brix% (range)

Evercrisp

19.7 (18-21.5)

4.4 (3-6)

15.2 (14-16.5)

Fuji

18.2 (15-21)

5.9 (5-7)

14.4 (13.8-15)

Granny Smith

19.2 (17-23.5)

3.6 (3-5)

13

Pink Lady

20.7 (15-23.5)

2.8 (1-6)

13.5 (12.5-14)

Braeburn

22.8 (21-25.3)

3.6 (2-6)

11.6 (10.3-12.8)

Individual variety results

Evercrisp

Evercrisp continues to move slowly in maturity parameters. Some have been harvested where red color is good, and the background color has changed from a dark green to a lighter green or somewhat yellow color. Red color is very much improved in this week’s sample, up to 81% from last week’s 63%. They are still very firm at almost 20 pounds of pressure. The starch index is improved from 3.8 last week to 4.4 this week. Brix are excellent at 15.3%.

Evercrisp 2019 maturity sampling records

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)

Oct. 8

0.4050

80

67.8 (40-90)

2.3 (1-3)

21.6 (19.5-24.2)

4.3 (2-7)

13.8 (12-16)

Oct. 15

0.4956

80

63 (30-100)

2

23.6 (20-26)

3.8 (2-8)

14.6 (14-16)

Oct. 22

0.7906

90

80.5 (50-100)

2.6 (1-3)

19.7 (18-21.5)

4.4 (3-6)

15.2 (14-16.5)

Fuji

Our predicted harvest date for late-season Fuji is Oct. 28, which will be much too late for long-term controlled atmosphere (CA) storage. This week will likely finish up Fuji harvest for the season. They are in the window for long-term CA storage right now with 18.2 pounds of pressure, starch clearing in the 5 to 7 range and excellent brix readings at 14.4. Very little water core is being reported in Fuji so far.

In years past when sugar levels are high as they seem to be this year, Fuji (and other varieties) can get callus tissue inside the core. This often is mistaken by buyers for moldy core. Buyers have tried to reject loads for this non-defect. Check out “Moldy Core of Apple” from Kari Peters at Penn State University for a good comparison of moldy core and callus tissue with pictures to help with identification.

Fuji 2019 maturity sampling records

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)

Oct. 1

0.6593

7

85 (50-100)

1.7 (1-2)

18.5 (15.3-25.5)

2.6 (1-6)

13.9 (12-16)

Oct. 8

1.1089

100

89 (80-100)

1.8 (1-2)

18 (15.5-20.5)

4.6 (3-7)

14.6 (14-16.5)

Oct. 15

0.3813

65

93 (60-100)

1.5 (1-2)

18.2 (14-23)

5.6 (3-8)

14.9 (14-16)

Oct. 22

0.4686

70

85 (60-95)

1.4 (1-2)

18.2 (15-21)

5.9 (5-7)

14.4 (13.8-15)

Granny Smith

Granny Smith has moved very slowly forward in maturity. Internal ethylene is very low with no fruits reading over the 0.2 ppm climacteric. The background color is still very green, but they are a green apple after all, so this isn’t as important as in other varieties.

Fruit firmness is excellent at 19.2 pounds. The starch clearing is improved to an average of 3.6 this week compared to 2.2 last week. Brix levels are really good (for Granny Smith) at 13%. They could stay on the tree for another week or more and still stay in condition, but growers will harvest Grannies when they want to get harvest completed.

Granny Smith 2019 maturity sampling records

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)

Oct. 8

0

0

3.9 (0-10)

4.3 (3-5)

18.7 (16.5-20.5)

2

11.3 (11-12)

Oct. 15

0.0476

0

1 (0-5)

3

21 (18-24.5)

2.2 (1-4)

12.3 (12-13)

Oct. 22

0.0590

0

1 (0-5)

3.3 (3-4)

19.2 (17-23.5)

3.6 (3-5)

13

Pink Lady

We added a Pink Lady sample this week. This is from a Maslin strain block where reversion is suspected and our data support this theory—the ranges in individual apple maturity are all over the board with some fruits nearing ideal maturity right now and others seeming like they need a week or more (as a regular Pink Lady would). Red color is improving nicely with Pink Lady and when you are satisfied with red color, it’s time to pick.

Fruit tested are very firm on average at 20.7 pounds, but there were some fruits with pressures in the 15- to 16-pound range. Starch clearing averaged 2.8, but the range across all fruits was from 1 to 6, so quite variable. Brix are good to very good at 13.5 and some improvement would help with eating quality in another week or so.

Pink Lady 2019 maturity sampling records

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)

Oct. 22

2.664

10

90.4 (70-100)

1.6 (1-2)

20.7 (15-23.5)

2.8 (1-6)

13.5 (12.5-14)

Braeburn

We added Braeburn to our sampling this week. The predicted harvest date for Braeburn in the Grand Rapids area is Oct. 28, which will likely be a good target date. However, they could be harvested slightly ahead of that date as growers want to wrap up harvest soon. Braeburn is very low in the area of internal ethylene with only 10% of fruits over the 0.2 ppm climacteric.

Red color is good at 54% and needs some improving for best marketability. They are extremely firm at 22.8 pounds on average with some fruits over 25 pounds. Starch clearing is averaging 3.6, which is in the range for long-term CA storage, but a bit on the low side yet. Brix are low at 11.6 on average. One more week will greatly improve the eating quality for Braeburn.

Braeburn 2019 maturity sampling records

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)

Oct. 22

0.1388

10

54 (40-70)

2.7 (2-3)

22.8 (21-25.3)

3.6 (2-6)

11.6 (10.3-12.8)

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.
 


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