Southwest Michigan apple maturity report – October 10, 2023
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EmailSouthwest Michigan apple harvest focuses on Fuji, Rome and IdaRed 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
Fuji, Rome and IdaRed are the focus of harvesting in the southwest Michigan area, with a few Goldens and Red Delicious finishing up. Apples in southwest Michigan have been relatively free of bitter pit and diseases problems so far.
Fuji
Main season Fuji varieties are averaging 5.6 for the starch test, significantly above the starch threshold of 3, considered mature. The current area average firmness reading is 15.9 pounds, compared to the long term controlled atmosphere (CA) target value of 18 pounds, a drop of 1.5 pounds. Brix has improved significantly since last week. About half of the main season Fujis in the area have been harvested. Delayed harvest of Fuji past prime maturity increases the chances for watercore, although this disorder is less common in the southwest region this year. Other apple production areas in Michigan with more challenging weather conditions have experienced some watercore issues in Fuji this year.
|
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) |
|
Sep. 25 |
67 (30-90) |
17.4 (16.9-18.2) |
4.2 (3.6-5.2) |
11.7 (11-12.2) |
|
Oct. 2 |
67.9 (60-75) |
17.4 (16.9-17.9) |
4.5 (3.8-6) |
12.1 (11.8-12.8) |
|
Oct. 9 |
81.0 (50-98) |
15.9 (15.1-16.6) |
5.6 (4.2-7) |
13.5 (11.7-15) |
*Starch values according to the 1-8 scale developed by Cornell University.
IdaRed
This variety is averaging 4.4 for the starch test, the mature starch threshold is 3.5. The current average firmness reading is 14.9 pounds, compared to the long term CA target value of 16 pounds. The predicted peak harvest date for central Berrien County is Oct. 4, and appears to be generally correct. Most of the IdaRed orchards are being picked now or have already been picked.
|
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) |
|
Sep. 25 |
82.6 (50-98) |
16.9 (15.6-17.8) |
3.2 (3-3.8) |
11.4 (10.6-11.8) |
|
Oct. 2 |
84.9 (60-100) |
15.6 (15.4-16.2) |
3.7 (3.2-4.2) |
11.5 (10-12.1) |
|
Oct. 9 |
84.0 (60-100) |
14.9 (14.4-15.6) |
4.4 (3.6-5) |
11.9 (11.1-12.6) |
*Starch values according to the 1-8 scale developed by Cornell University.
Rome
This variety is averaging 4.6 for the starch test, the mature starch threshold is 3. The current average firmness reading of 19.3 pounds is still 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. A few Romes are being harvested in the area.
|
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) |
|
Sep. 25 |
82.5 (50-98) |
22.5 (19.9-24.6) |
3.6 (3-4.4) |
10.7 (10-11.4) |
|
Oct. 2 |
88.1 (70-100) |
19.9 (19-22) |
4 (3.4-4.6) |
10.9 (10.4-11.5) |
|
Oct. 9 |
89.0 (70-100) |
19.3 (18.6-20.2) |
4.6 (4-5.2) |
11.8 (10.9-12.3) |
*Starch values according to the 1-8 scale developed by Cornell University.
Evercrisp
This variety is averaging 2.9 for the starch test, the mature starch threshold is 3. The current average firmness reading of 19.8 pounds is still very firm—the long term CA storage target value for this variety is 18 pounds. We currently do not have a predicted harvest date for this variety, but based on the firmness and starch tests, harvesting of more mature sites with better blush development would be appropriate. Brix has reached an average of 13.8, with one site at 14.6. Like Fuji, this variety is prone to watercore in some years if harvested overmature. No watercore was detected this week in the three orchards sampled in southwest Michigan
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Sep. 25 |
67.5 (50-90) |
23.4 (22.7-25.4) |
1.7 (1-3) |
12.6 (10.9-13.3) |
|
Oct. 2 |
70 (50-90) |
21.2 (19.6-22.4) |
3.3 (2.4-3.6) |
13 (12.3-14.4) |
|
Oct. 9 |
71 (50-95) |
19.8 (17.7-21.6) |
2.9 (2.4-3.8) |
13.8 (12.4-14.6) |
*Starch values according to the 1-8 scale developed by Cornell University.
Braeburn
This variety is averaging 3.7 for the starch test, the same as last week--the mature starch threshold is 2.5. The current average firmness reading of 19.4 pounds is very firm—the long term CA storage target value for this variety is 18 pounds. Brix is inching up, but still relatively low. We are seeing a wide range of starch readings from 2 to 5.8, so checking individual blocks for maturity would be a good idea.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Oct. 2 |
68.5 (50-98) |
20.3 (18.7-22.2) |
3.7 (2.6-4.6) |
10.9 (9.7-11.4) |
|
Oct. 9 |
76.0 (40-95) |
19.4 (18.4-20.4) |
3.7 (2-5.8) |
11.6 (10.1-13.1) |
*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.
