Grand Rapids area apple maturity report – September 11, 2024
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EmailFourth apple maturity report for the Grand Rapids region.
Apple harvest is moving right along. Galas and Honeycrisp are wrapping up this week. Empires and Jonathans are currently mature. Fujis, Ambrosia, Golden Delicious and Red Delicious are on deck. Contact me brow1111@msu.edu if you would like me to test other varieties or sample your fruit.
Sunburn and bitter pit
Bitter pit is very common across the state 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. Sunburn symptoms look like a reddened, sunken area on the apple that has a thin, pithy layer underneath the skin.
I am sampling internal ethylene this year. 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.
Stop-drop materials can be very useful to manage harvest windows during this early season, especially if color is a concern. 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. 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 overmature and have largely been harvested in the area.
|
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) |
|
9/9/2024 |
201 (143-277) |
75.6 (68.9-86.5) |
70.5 (40-90) |
1.1 (1-2) |
100% |
15.15 (13.78-17.93) |
6.8 (6-8) |
13.7 (12.8-15) |
Fuji
This variety was sampled at three locations in Kent County this week. The later season Fujis are now about a week away from maturity. While the sugars and firmness remain steady from last week, the starch clearing and the internal ethylene are progressing. Their color is developing well.
|
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) |
|
9/9/2024 |
168.8 (117-246) |
71.3 (63.1-80) |
66.5 (30-85) |
2.3 (2-3) |
37% |
20.7 (17.76-25.67) |
2.3 (1-4) |
10.77 (10-12) |
Gala
This variety was sampled across three locations in Kent County this week. Gala harvest is wrapping up in the area this week. While the sugars are not ideal for harvest, 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) |
|
9/9/2024 |
153.6 (110-203) |
68.3 (60.8-76.2) |
85.8 (65-95) |
1 (1-1) |
96% |
18.05 (14.72-25.05) |
5.2 (2-8) |
10.82 (10-12.2) |
Honeycrisp
This variety was sampled across four locations in Kent County this week. Honeycrisp harvest is wrapping up in the area this week. Note that the average firmness is below controlled atmosphere (CA) storage recommendations and the starch clearing is now overmature. The internal ethylene indicates that this variety should be harvested very soon. These apples taste excellent, and the sugars are well developed.
|
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) |
|
9/9/2024 |
282.8 (181-424) |
86.86 (73.8-101.2) |
71.8 (40-90) |
1.5 (1-3) |
100% |
14.64 (10.5-18.7) |
7.0 7 (6-8) |
13.9 (11-16) |
McIntosh
This variety was sampled at two locations in Kent County. McIntosh varieties are now overmature, based on firmness, starch clearing and internal ethylene.
|
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) |
|
9/9/2024 |
114.7 (79-177) |
65.84 (56.4-73.3) |
94 (90-95) |
2.2 (2-3) |
100% |
14.45 (11.82-16.91) |
7 (6-8) |
10.5 (10-11.2) |
For more information about regional reports, please visit the Michigan State University Extension website.
