Grand Rapids area apple maturity report – September 4, 2024
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EmailThird apple maturity report for the Grand Rapids region.
Apple harvest is well underway! Early Fujis, Honeycrisps and Galas are being harvested across the area now.
Bitter pit is very common across Michigan this year in Honeycrisp blocks. The excessive heat earlier in the season was associated with higher rates of transpiration, which pulls calcium into the leaves and away from the fruit. The high temperatures this season has also shown up in sunburn around the state.
I started sampling internal ethylene this week, with the help of Randy Beaudry. When reading those values, keep in mind that the percentage refers to the percent of sampled apples that exceeded 0.2 parts per million (ppm) internal ethylene. If over 50% of samples have this value, then they are ripening on their own and cannot be held back with stop-drop materials easily. Higher internal ethylene can have reduced long term storage capacity. In practical terms, they should be prioritized for harvest.
Please keep in mind that stop-drop materials can be very useful to manage harvest windows during this early season, especially if color is a concern, but the window to effectively use them may be sooner rather than later.
This is a difficult harvest season to balance between harvest metrics like starch testing and internal ethylene and fruit quality like sugars and reddening. Stop-drop materials, reflective ground covers, and summer pruning are being used effectively throughout the region to encourage color. Please keep in mind that waiting to harvest can impact the long-term storage and quality of the crop. Maintaining fruit quality and long-term integrity is crucial this year.
Some of these varieties coming into maturity are even exceeding the early predicted harvest dates by Michigan State University (MSU) this year. Frequent proactive sampling will be needed to stay on top of harvest. Please let me know if there are other varieties you would like me to sample.
Auvil Early Fuji
This variety was sampled at one location in Kent County this week. Early Fujis are currently mature according to the firmness, sugars and ethylene. The starches indicate that they are moving towards over maturity. These apples taste excellent.
|
Collection Date |
Weight |
Diameter (mm) |
Red Color (%) |
Background Color |
Ethylene (%) |
Firmness (lbs) |
Starch |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|---|---|
|
8/20/2024 |
|
71 (83.7 - 57.5) |
48.5 (30 - 80) |
2.3 (1 - 3) |
|
22.2 (15.4 - 18.8) |
4.5 (4-5) |
11.7 (10.8 - 14) |
|
9/3/2024 |
229.2 (150 - 285) |
78.7 (67.5-87.5) |
58 (30-80) |
1.6 (1-2) |
80% |
15.6 (13.5-22.9) |
5.8 (4-8) |
12.9 (10.8-14.2) |
Fuji
This variety was sampled at three locations in Kent County this week. The later season Fujis are still a few weeks away from maturity. They continue to gain color and sugars.
|
Collection Date |
Weight (g) |
Diameter (mm) |
Red Color (%) |
Background Color |
Ethylene (%) |
Firmness (lbs) |
Starch |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|---|---|
|
8/20/2024 |
|
68.2 (59.4 - 74.5) |
43 (20 - 70) |
2.5 (2-3) |
|
22.4 (19.7 - 29.4) |
1.8 (1 - 2) |
9.1 (9 - 9.3) |
|
8/28/2024 |
147.2 (86-220) |
68.1 (60-79)
|
55.3 (30-90) |
2.3 (1-3) |
|
23.3 (20.4-27.7) |
2.1 (1-3) |
10 (9.4-11) |
|
9/3/2024 |
157 (122-201) |
70.2 (64.6-78.1) |
62.8 (35-85) |
2.3 (1-3) |
13% |
20.9 (18.7-25.6) |
1.9 (1-3) |
10.6 (10-13) |
Gala
This variety was sampled across three locations in Kent County this week. Galas are currently being harvested. Galas are a bit small this year. While the sugars and firmness are not ideal for harvest currently, the starch clearing is progressing towards over maturity and the internal ethylene was high across the samples. Balancing fruit quality and storability is key for this variety this year.
|
Collection Date |
Weight (g) |
Diameter (mm) |
Red Color (%) |
Background Color |
Ethylene |
Firmness (lbs) |
Starch |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|---|---|
|
8/20/2024 |
|
68.9 (57.6 - 82) |
76.8 (15 - 95) |
1.6 (1-3) |
|
21.3 (16.4 - 27.6) |
2.4 (1 - 4) |
10.2 (9 - 13.8) |
|
8/28/2024 |
155 (109-222) |
68.8 (33-72) |
82.5 (30-95) |
1 (1-1) |
|
20.3 (16.7-27.8) |
3.2 (1-5) |
10.3 (8.8-12) |
|
9/3/2024 |
151.7 (116-260) |
68 (62.3-83.2) |
85.3 (65-95) |
1.0 (1-2) |
87% |
19 |
4.5 (2-8) |
11.0 (9-13) |
Honeycrisp
This variety was sampled across four locations in Kent County this week. Honeycrisp is quickly coming off the trees across the area. Note that the average firmness is dropping below controlled atmosphere (CA) storage recommendations and the starch clearing is becoming overmature. The internal ethylene indicates that this variety should be harvested very soon. These apples taste excellent, and the sugars are good. The reddening was further along this week.
|
Collection Date |
Weight (g) |
Diameter (mm) |
Red Color (%) |
Background Color |
Ethylene |
Firmness (lbs) |
Starch |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|---|---|
|
8/20/2024 |
|
80.1 (68.1 - 101.9) |
58.9 (20 - 95) |
2 (1 - 3) |
|
16.3 (11.5 - 21.7) |
3.5 (1 - 7) |
12.1 (10.2 - 14) |
|
8/28/2024 |
222.9 (131-222) |
79.2 (65-94) |
64.3 (20-95) |
2.1 (1-3) |
|
16.4 (14.1-27.8) |
5.03 (3-5) |
12.2 (10.5-12.2) |
|
9/3/2024 |
259.9 (151-363) |
84.5 (70.4-98.4) |
78.8 (35-296) |
1.4 (1-2) |
85% |
14.9 (10.43-18.2) |
6.8 (5-8) |
13.4 (11.1-15) |
McIntosh
This variety was sampled at two locations in Kent County. Keep an eye on RubyMacs and LindaMacs this upcoming week when making harvest decisions. Sugar levels are fair and firmness and starch are in line with maturity metrics. Color is good on McIntosh sports in the area this week. The internal ethylene is still low on this variety.
|
Collection Date |
Weight (g) |
Diameter (mm) |
Red Color (%) |
Background Color |
Ethylene |
Firmness (lbs) |
Starch |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|---|---|
|
8/28/2024 |
140.7 (82-227) |
71.0 (60.6-85.3) |
75.7 (40-95) |
2.4 (1-4) |
|
16.6 (12.4-19.4) |
5.0 (4-6) |
10.7 (10-12.8) |
|
9/3/2024 |
138 (76-227) |
70.8 (59-86.7) |
78.8 (35-100) |
2.1 (1-3) |
10% |
15.8 (14.5-18.0) |
5.8 (4-7) |
11.4 (10-12.8) |
For more information about regional reports, please visit the Michigan State University Extension website.
