Southwest Michigan apple maturity report – September 14, 2022
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EmailGala harvest is finishing up with Jonagold and Honeycrisp mature for many orchards in the southwest Michigan area. Brown marmorated stink bug trap catches have increased significantly over the past week.
This is our weekly southwest region apple maturity reports. Reports are sent out on Wednesdays, following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning.
- Predicted apple harvest dates for 2022 from MSU
- More information on harvest management tools and timings can be found in this article.
- Guidelines from MSU 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.
Additional notes:
The recent rains will be encouraging rot fungi development in stored fruit. Growers that have been on active summer disease programs should be in good shape. Pristine + Captan or Merivon + Captan would be the best preharvest materials to minimize storage rot problems.
MDARD has a NEW Pesticide Applicator Credit Report on MDARD’s website under recent additions section at https://www.michigan.gov/mdard/licensing/pesticide. Michigan pesticide applicators can look up the number of credits they have on their credential.
How to read the maturity tables
We test apple varieties that are nearing maturity in the southwest Michigan area, with focus on Berrien County. We are reporting average values for firmness, starch index and brix for several samples for each variety. Maximum and minimum values are included for the highest and lowest average for individual orchards.
Gala (main season types)
Gala internal maturity continues to improve with fruit pressure averaging 18.6 lb, and starch conversion averaging 5.4, with 3 considered mature. The predicted central Berrien County harvest date is Sept. 6.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-6) |
Soluble Solids (°Brix) |
|
Aug 22 |
60 (55-65) |
22.3 (21-24) |
1.1 (1-1.6) |
10.2 (9.4-11.3) |
|
Aug 29 |
82 (62-95) |
21.1 (20-23) |
2.8 (1.6-4.4) |
11.2 (10.2-12.4) |
|
Sept 6 |
83 (65-90) |
19.3 (17.2-21) |
3.7 (2-5.6) |
12.0 (11.3-13.1) |
|
Sept 12 |
94 (85-100) |
18.6 (17.3-20.4) |
5.4 (4.2-6) |
12.7 (11.3-14.1) |
Mac
No new samples this week, this variety is at full maturity in the central southwest Michigan region.
Jonagold
Internal starch conversion is averaging 3.7, considered mature, still with excellent firmness. Newer Jonagold varietal strains have good blush, but all strains have greenish backgrounds. The predicted harvest date for central Berrien County is Sept. 21.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-6) |
Soluble Solids (°Brix) |
|
Aug 29 |
N/A |
19.4 (18.2-21) |
2 (2-2) |
12 (11.7-12.2) |
|
Sept 6 |
73.4 (50-99) |
18.5 (17-21.3) |
2.3 (2-3.2) |
11.4 (10.8-12) |
|
Sept 12 |
69.8 (30-99) |
17.8 (16.2-20) |
3.7 (2-5.4) |
12.1 (11.5-13.6) |
Honeycrisp (main season)
Second week of sampling for this variety. Fruit background color is still green. Starch conversion is relatively advanced, averaging 6.7, with 3.5 considered mature. Fruit firmness is averaging 14.4 lbs, appropriate for short term-controlled atmosphere storage. Fruit size in some orchards with moderate to light crop is large (4” diameter). The predicted harvest date for central Berrien County is Sept. 11. MSU post-harvest research Randy Beaudry has summarized Honeycrisp harvest and storage recommendations, given here as a link.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-6) |
Soluble Solids (°Brix) |
|
Sept 6 |
60 (50-74) |
16.7 (16-18) |
4.4 (3.0-5.4) |
12.3 (11.9-12.7) |
|
Sept 12 |
60 (50-74) |
14.4 (14-15) |
6.7 (5.8-7) |
13.1 (12.6-14.2) |
Empire
Fruit starch conversion is still averaging in the immature range. The estimated harvest day for central Berrien County is Sept. 18.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-6) |
Soluble Solids (°Brix) |
|
Sept 6 |
59 (45-75) |
18.9 (18-19.4) |
2.4 (2-3) |
11.1 (10.4-11.9) |
|
Sept 12 |
64 (50-85) |
17.6 (17-18.1) |
2.7 (2-3.4) |
11.4 (10.9-12) |
Fuji (main season)
Second samples were taken this week. Fruit background color is still relatively green. Starch conversion is averaging 2.8, still immature but moving toward the mature range of 3.0. Firmness is still relatively high. The predicted harvest date for central Berrien County is Sept. 24.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-6) |
Soluble Solids (°Brix) |
|
Sept 6 |
55 (30-65) |
21 (19-24) |
2.4 (2-3) |
11.4 (10.4-12) |
|
Sept 12 |
48 (25-62) |
19.3 (18-20.4) |
2.8 (1.8-3) |
11.4 (10.6-12.1) |
Golden Delicious
First samples were taken this week. Fruit background color is still relatively green. Starch conversion is averaging 1.9, still immature, with 3.0 considered mature. Firmness is 17.1, close to the threshold of 17 for long-term controlled atmosphere storage. The predicted harvest date for central Berrien County is Sept. 24.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-6) |
Soluble Solids (°Brix) |
|
Sept 12 |
16.7 (12-30) |
17.1 (16.1-18) |
1.9 (1.2-2.4) |
11.4 (10.5-12.2) |
Red Delicious
First samples were taken this week. Fruit background color is still relatively green. Starch conversion is averaging 2.7, with 2.5 as the threshold for mature. Firmness at 17.4 is slightly below the threshold of 18 for long-term controlled atmosphere storage. Fruit maturity is moving ahead of the predicted harvest date for Red Delicious for central Berrien County of Sept. 29.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-6) |
Soluble Solids (°Brix) |
|
Sept 12 |
98 (98-99) |
7.4 (16.4-18) |
2.7 (2-3) |
9.9 (9.3-10.8) |
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 |
6 |
|
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 |
|
Normal and predicted 2022 peak harvest dates for apple varieties in central Berrien County in southwest Michigan based on weather data at the Southwest Michigan Research and Extension Center, Benton Harbor, MI. |
||
|
Variety |
Normal date |
2022 Predicted peak harvest date |
|
Zestar |
22-Aug |
20-Aug |
|
Paula Red |
22-Aug |
20-Aug |
|
Gingergold |
20-Aug |
18-Aug |
|
Gala |
8-Sep |
6-Sep |
|
McIntosh |
10-Sep |
8-Sep |
|
Early Fuji |
3-Sep |
1-Sep |
|
Honeycrisp |
13-Sep |
11-Sep |
|
Empire |
19-Sep |
18-Sep |
|
Jonathan |
22-Sep |
21-Sep |
|
Jonagold |
22-Sep |
21-Sep |
|
Fuji |
25-Sep |
24-Sep |
|
Golden Delicious |
25-Sep |
24-Sep |
|
Red Delicious |
28-Sep |
29-Sep |
|
Ida Red |
5-Oct |
6-Oct |
|
Rome |
5-Oct |
6-Oct |
|
Braeburn |
20-Oct |
21-Oct |
|
Goldrush |
26-Oct |
27-Oct |
Predictions are for the first significant harvest date rather than peak harvest. Also note that the normal harvest date for Fuji is approximately three weeks ahead of the normal date given in previous years reports. Newer strains of Fuji have much earlier and more extensive red blush development than older strains. In the past harvest of Fuji was delayed past optimum internal maturity to wait for better blush development. This delay has resulted in increased storage problems, including watercore and internal browning.
