Southwest Michigan apple maturity report – September 20, 2023
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EmailSouthwest Michigan apple harvest will be moving soon to harvesting Fuji, Jonagold and Yellow Delicious apples.
This is our weekly southwest region apple maturity report. Reports are sent out following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning. View Michigan State University Extension’s Apple Maturity page for regional reports throughout the state and additional resources.
Report overview
Honeycrisp is nearly all harvested in central Berrien County. Maturity of Jonagold, Golden Delicious and Fuji has progressed rapidly.
Empire
The current average firmness reading of 15.4 pounds is close to the long-term controlled atmosphere (CA) storage target value of 16 pounds. Overall, the current average starch reading of 4.1 has passed the 3.5 mark considered mature, although some sites are averaging below 3.0. The predicted peak harvest date for Central Berrien County is Sept. 14. Over 50% of the area Empire crop has been harvested for processing.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 5 |
65 (30-98) |
16.3 (15.4-17.1) |
N/A |
10.1 (9.4-11.6) |
|
Sep. 12 |
78 (40-99) |
17 (16.1-17.6) |
2.9 (2.8-3) |
10.8 (10-11.9) |
|
Sep. 19 |
88 (60-99) |
15.4 (15-15.7) |
4.1 (2.8-4.8) |
11.4 (10.8-12.4) |
*Starch values according to the 1-8 scale developed by Cornell University.
Jonagold
This variety is averaging 6.5 for the starch test, well over the starch threshold of 3.5, considered mature. The current average firmness reading of 15.7 pounds is close to the mid-term CA storage target value of 16 pounds. Background color is still noticeably green. This variety is maturing ahead of the predicted peak harvest date of Sept. 19 for central Berrien County. Most Jonagolds remain to be harvested in the central Berrien County area.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 12 |
77.2 (50-100) |
16.8 (15.9-18) |
5.1 (2.6-7) |
11.8 (10-12.9) |
|
Sep. 19 |
73.2 (40-100) |
15.7 (15.2-16.1) |
6.5 (5.8-7) |
11.4 (10.6-11.9) |
*Starch values according to the 1-8 scale developed by Cornell University.
Fuji
Main season Fuji varieties are averaging 3.3 for the starch test, slightly above the starch threshold of 3, considered mature. The current area average firmness reading is 17.4 pounds, compared to the long-term CA target value of 18 pounds. This variety appears to be maturing close but slightly ahead of the predicted peak harvest date of Sept. 23 for Central Berrien County. Main season Fujis are generally still on the tree waiting to be picked.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 12 |
65.8 (40-98) |
19.2 (17.9-20) |
2.5 (2-3) |
10.8 (10.1-12) |
|
Sep. 19 |
63.1 (30-90) |
17.4 (15-18) |
3.3 (2.6-4.6) |
10.7 (9.9-11.1) |
*Starch values according to the 1-8 scale developed by Cornell University.
Golden Delicious
This variety is averaging 3.7 for the starch test, somewhat above the starch threshold of 3 consider mature. The current average firmness reading of 16.5 pounds is close to the long-term CA target value of 17 pounds. The predicted peak harvest date for Central Berrien County is Sept. 24. Background color is noticeably green. Goldens generally have not been harvested in the southwest region.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 12 |
16.6 (8-40) |
16.9 (16-17.3) |
2.3 (1-3.6) |
11.2 (9.9-11.9) |
|
Sep. 19 |
14.8 (0-45) |
16.5 (15.4-17.8) |
3.7 (2-6) |
11.8 (10.7-13.3) |
*Starch values according to the 1-8 scale developed by Cornell University.
Red Delicious
This variety is averaging 3 for the starch test, the mature starch threshold is 2.5. The current average firmness reading is 17 pounds compared to the long-term CA target value of 18 pounds. This variety is maturing ahead of the predicted peak harvest date for Central Berrien County of Sept. 27. This variety has not been harvested yet in the central Berrien County area.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 19 |
97.2 (85-99) |
17 (15.9-17.5) |
3 (2.4-3.6) |
10.4 (9.6-11.6) |
*Starch values according to the 1-8 scale developed by Cornell University.
IdaRed
This variety is averaging 2.5 for the starch test, the mature starch threshold is 3.5. The current average firmness reading is 16.5 pounds, compared to the long-term CA target value of 16 pounds. The predicted peak harvest date for Central Berrien County is Oct. 4.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 19 |
74.6 (50-98) |
16.5 (16-17) |
2.5 (2-3) |
11 (10.4-11.5) |
*Starch values according to the 1-8 scale developed by Cornell University.
Rome
This variety is averaging 3.2 for the starch test, the mature starch threshold is 3. The current average firmness reading of 21.8 pounds is very firm—the long-term CA storage target value for this variety is 18 pounds. The predicted peak harvest date for Central Berrien County is Oct 4.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 19 |
84.2 (60-100) |
21.8 (20.1-25) |
3.2 (2.4-3.8) |
10.4 (9.9-10.7) |
*Starch values according to the 1-8 scale developed by Cornell University.
Apple maturity sampling parameters
- Color % = the visual percentage of red color (blush) from 0 to 100; range is of all fruits tested.
- Firmness in pounds pressure = measured with a FT Penetrometer; 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.
- Starch for Honeycrisp: a separate starch chart for Honeycrisp apples developed by Washington State University (scale 1-6).
- Brix = % sugar measured with Atago PAL-1 Pocket Refractometer
Looking for more? View Michigan State University Extension’s Apple Maturity page for regional reports throughout the state and additional resources.
|
Suggested firmness and starch index levels for long-term and shorter-term controlled atmosphere (CA) storage by variety. |
|||||
|
Variety |
Firmness (pounds)* |
Starch Index* |
|||
|
Short CA |
Mid-CA |
Long CA |
Mature |
Over mature |
|
|
McIntosh |
14 |
15 |
16 |
5 |
7 |
|
Gala |
16 |
17 |
18 |
3 |
6 |
|
Honeycrisp |
15 |
16 |
17 |
3.5 |
7 |
|
Empire |
14 |
15 |
16 |
3.5 |
6 |
|
Early Fuji |
16 |
17 |
18 |
3 |
7 |
|
Jonagold |
15 |
16 |
17 |
3.5 |
5.5 |
|
Jonathan |
14 |
15 |
16 |
3.5 |
5.5 |
|
Golden Delicious |
15 |
16 |
17 |
3 |
6.5 |
|
Red Delicious |
16 |
17 |
18 |
2.5 |
6 |
|
Idared |
14 |
15 |
16 |
3.5 |
6 |
|
Fuji |
16 |
17 |
18 |
3 |
7 |
|
Rome |
15 |
16 |
18 |
3 |
5.5 |
See the following helpful resources for more information:
- Predicted apple harvest dates for 2023 from MSU Extension.
- More information on harvest management tools and timings from MSU Extension.
- Post harvest treatments to extend apple life.
- Guidelines from MSU Extension to check for apple maturity in your own orchard, including specific pressure and starch recommendations by variety.
- Predicting apple maturity and starch chart from Cornell University.
- Starch chart for Honeycrisp apples developed by Washington State University.
