Southwest Michigan apple maturity report – Sept. 22, 2021
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EmailThis is the fourth weekly apple maturity report for the southwest Michigan region.
This apple maturity report for the southwest Michigan region is sent out every week (usually on Wednesdays) following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning.
Highlights for this week
Apple maturity is rapid for mid- to early late season varieties Empire, Golden Delicious, Red Delicious and Fuji with some orchards ripe enough for start of harvest. Current harvesting work in Berrien County has focused on Empire, Jonathan and Golden Delicious for processing.
Brown marmorated stink bug activity increased significantly over the past week as seen in trap catches and on sunny sides of buildings. Borders of apple orchards close to woods, buildings and soybean fields are usual places where damage starts.
Detailed information by variety
Mac, Gala and Honeycrisp
No more reports for these three varieties, now at full maturity.
Jonagold
Jonagold were sampled for the third week. Starch indices average 4.9, a significant jump over 3.2, with four of five sites tested averaging over 3.5, and considered mature. Fruit firmness has dropped approximately 2 pounds since last week and is averaging 17.6 pounds, slightly above the long-term controlled atmosphere (CA) storage threshold of 17 pounds.
This variety is maturing ahead of the predicted harvest date of Sept. 25 for central Berrien County. However, Jonagold skin red blush development has been slow this season, which is a problem for fruit to be sold for fresh consumption, but not for processing. Some area Jonagold have been harvested for processing.
Jonagold – Sampled Sept. 20, 2021
|
Site |
Firmness (lbs) |
Red color range (%) |
Starch
|
Soluble solids (°Brix) |
|
1 |
20.4 |
90-95 |
3.2 |
15.0 |
|
2 |
15.2 |
15-60 |
6.4 |
12.5 |
|
3 |
16.4 |
40-90 |
5.0 |
14.9 |
|
4 |
16.0 |
50-75 |
5.6 |
13.4 |
|
5 |
20.0 |
40-85 |
4.4 |
15.2 |
|
Average |
17.6 |
|
4.9 |
14.2 |
|
Max |
20.4 |
|
6.4 |
15.2 |
|
Min |
15.2 |
|
3.2 |
12.5 |
|
Recommended |
17-15 |
|
3.5 |
|
|
Jonagold maturity sampling for the harvest season |
|||
|
Sample date |
Firmness pounds (range) |
Starch (range) |
Brix % |
|
Sept. 7 |
20.7 (18.2-23.3) |
2.2 (1.2-3.0) |
12.6 |
|
Sept. 13 |
19.5 (16.2-23.0) |
3.2 (2.0-4.6) |
13.6 |
|
Sept. 20 |
17.6 (15.2-20.4) |
4.9 (3.2-6.4) |
14.2 |
Jonathan
This variety was sampled for the third week, with now the starch conversion testing at an average of 5.2 pounds—a sizable jump over last week. This week, three out of four sites tested starch conversion values above 3.5, indicating fruit are internally mature. Also, flesh firmness dropped 1 pound to 16.1, now at the level where fruit transition from long term CA quality to a level more suited for shorter term storage. Some Jonathan have been harvested for taffy apples.
Jonathan – Sampled Sept. 20, 2021
|
Site |
Firmness (lbs) |
Red color range (%) |
Starch |
Soluble solids (°Brix) |
|
1 |
18.1 |
60-85 |
3.0 |
13.8 |
|
2 |
15.0 |
40-85 |
3.8 |
13.6 |
|
3 |
15.3 |
60-98 |
6.4 |
13.7 |
|
4 |
16.0 |
40-95 |
7.4 |
12.6 |
|
Average |
16.1 |
|
5.2 |
13.4 |
|
Max |
18.1 |
|
7.4 |
13.8 |
|
Min |
15.0 |
|
3.0 |
12.6 |
|
Recommended |
16-14 |
|
3.5 |
|
|
Jonathan maturity sampling for the harvest season |
|||
|
Sample date |
Firmness pounds (range) |
Starch (range) |
Brix % |
|
Sept. 7 |
20.0 (19.0-21.0) |
3.3 (3.0-3.8) |
12.2 |
|
Sept. 13 |
17.9 (17.1-19.2) |
3.4 (3.0-4.0) |
12.6 |
|
Sept. 20 |
16.1 (15.0-18.1) |
5.2 (3.0-7.4) |
13.4 |
Empire
This variety was sampled for the third week. Firmness dropped about 1 pound since last week but is still very good, now at an average of 16.3 pounds for the four sites. Starch conversion has reached 3.8, above the 3.5 considered to be the threshold for internally mature. Brix is averaging about 1% higher than last week. Harvesting for fresh consumption can be delayed a short while to wait for better sugar development. The predicted harvest date for central Berrien County is Sept. 21, a reasonably accurate prediction. Some Empire have been harvested for taffy apples
Empire – Sampled Sept. 20, 2021
|
Site |
Firmness (lbs) |
Red color range (%) |
Starch |
Soluble solids (°Brix) |
|
1 |
17.0 |
70-98 |
4.0 |
12.8 |
|
2 |
16.0 |
50-85 |
2.6 |
12.1 |
|
3 |
16.3 |
98-100 |
3.4 |
12.6 |
|
4 |
16.0 |
30-70 |
5.2 |
11.7 |
|
5 |
|
|
|
|
|
Average |
16.3 |
|
3.8 |
12.3 |
|
Max |
17.0 |
|
5.2 |
12.8 |
|
Min |
16.0 |
|
3.4 |
10.0 |
|
Recommended |
16-14 |
|
3.5 |
|
|
Empire maturity sampling for the harvest season |
|||
|
Sample date |
Firmness pounds (range) |
Starch (range) |
Brix % |
|
Sept. 7 |
19.4 (17.4-22.1) |
2.9 (2.0-4.0) |
11.2 |
|
Sept. 13 |
17.5 (16.2-20.0) |
3.4 (3.0-4.2) |
11.2 |
|
Sept. 20 |
16.3 (16.0-17.0) |
3.8 (3.4-5.2) |
12.3 |
Golden Delicious
This variety was sampled for the second week. Firmness is testing an average of 17.4 pounds, about the same as last week. This is only slightly above 17, the lower range considered ideal for long term CA storage. Starch conversion average is 3.5, above the 3.0 considered to be point where fruit become internally mature. This variety appears to be slightly ahead of the predicted harvest date of Sept. 28 for central Berrien County.
Golden Delicious – Sampled Sept. 20, 2021
|
Site |
Firmness (lbs) |
Red color range (%) |
Starch |
Soluble solids (°Brix) |
|
1 |
16.0 |
0 |
2.6 |
12.5 |
|
2 |
17.0 |
10-15 |
3.0 |
13.4 |
|
3 |
19.0 |
20-30 |
3.8 |
13.8 |
|
4 |
17.0 |
0 |
2.8 |
12.5 |
|
5 |
16.2 |
5-10 |
4.8 |
12.4 |
|
6 |
19.1 |
15-30 |
3.8 |
14.1 |
|
Average |
17.4 |
|
3.5 |
13.1 |
|
Max |
19.1 |
|
4.8 |
14.1 |
|
Min |
16.0 |
|
2.6 |
12.4 |
|
Recommended |
17-15 |
|
3.0 |
|
|
Golden Delicious maturity sampling for the harvest season |
|||
|
Sample date |
Firmness pounds (range) |
Starch (range) |
Brix % |
|
Sept. 13 |
17.6 (16.0-20.0) |
2.9 (1.0-4.2) |
12.0 |
|
Sept. 20 |
17.4 (16.0-19.1) |
3.5 (2.6-4.8) |
13.1 |
Red Delicious
This variety was sampled for the second week. Firmness is testing an average of 18.4, close to 18, the range for long term CA storage. Starch conversion for the five sites tested an average of 3.8, already over 2.5, considered to be the threshold for internally mature. All six sites sampled are testing mature. This variety appears to be considerably ahead of the predicted harvest date, which is Oct. 3 for central Berrien County.
Red Delicious – Sampled Sept. 20, 2021
|
Site |
Firmness (lbs) |
Red color range (%) |
Starch |
Soluble solids (°Brix) |
|
1 |
17.0 |
70-100 |
3.4 |
11.5 |
|
2 |
17.4 |
40-100 |
4.0 |
9.4 |
|
3 |
17.0 |
70-95 |
6.0 |
11.9 |
|
4 |
18.0 |
80-95 |
4.0 |
11.5 |
|
5 |
16.2 |
85-98 |
2.6 |
11.1 |
|
6 |
19.0 |
100 |
3.0 |
12.8 |
|
Average |
17.4 |
|
3.8 |
11.4 |
|
Max |
19.0 |
|
6.0 |
12.8 |
|
Min |
16.2 |
|
2.6 |
9.4 |
|
Recommended |
18-16 |
|
2.5 |
|
|
Red Delicious maturity sampling for the harvest season |
|||
|
Sample date |
Firmness pounds (range) |
Starch (range) |
Brix % |
|
Sept. 13 |
18.4 (17.2-20.2) |
2.8 (2.0-4.0) |
10.2 |
|
Sept. 20 |
17.4 (16.2-19.0) |
3.8 (2.6-6.0) |
11.4 |
Fuji
This variety was sampled for the second time and flesh firmness is testing an average of 19.0 pounds, about 0.5 pounds lower this week, and still in the range recommended for fruit for long term CA storage. Starch conversion tested 3.0, right at the threshold for being considered internally mature. Red blush ranges from 10 to 85%. Fuji has a predicted harvest date of Sept. 28 for central Berrien County. This is a much earlier predicted date (about three weeks earlier) than in past years, due to a recalculation of the normal harvest date for this variety. The revised harvest date seems correct for central Berrien County.
Fuji (Main season) – Sampled Sept. 20, 2021
|
Site |
Firmness (lbs) |
Red color range (%) |
Starch |
Soluble solids (°Brix) |
|
1 |
19.0 |
40-80 |
3.0 |
13.5 |
|
2 |
16.1 |
45-85 |
4.0 |
11.8 |
|
3 |
19.0 |
15-20 |
3.0 |
11.9 |
|
4 |
21.0 |
60-80 |
2.0 |
13.4 |
|
5 |
20.0 |
10-25 |
3.0 |
12.2 |
|
Average |
19.0 |
|
3.0 |
12.6 |
|
Max |
21.0 |
|
4.0 |
13.8 |
|
Min |
16.1 |
|
2.0 |
11.8 |
|
Recommended |
18-16 |
|
3.0 |
|
|
Fuji maturity sampling for the harvest season |
|||
|
Sample date |
Firmness pounds (range) |
Starch (range) |
Brix % |
|
Sept. 13 |
17.5 (16.2-20.0) |
3.4 (3.0-4.2) |
11.2 |
|
Sept. 20 |
19.0 (16.1-21.0) |
3.0 (2.0-4.0) |
12.6 |
IdaRed
This variety was harvested for the first time this week and is predicted to be ready approximately Oct. 10 in central Berrien County. Fruit firmness is still excellent at an average of 18.1 pounds, with starch conversion testing an average of 2.0, well below the 3.5 considered internally mature. According to these tests, IdaRed harvest can be delayed. Some blocks have been harvested for processing.
IdaRed – Sampled Sept. 20, 2021
|
Site |
Firmness (lbs) |
Red color range (%) |
Starch |
Soluble solids (°Brix) |
|
1 |
18.3 |
60-90 |
2.0 |
13.3 |
|
2 |
20.0 |
70-98 |
1.0 |
13.6 |
|
3 |
16.1 |
30-60 |
2.0 |
11.0 |
|
4 |
17.3 |
50-95 |
2.8 |
12.0 |
|
5 |
19.0 |
60-98 |
2.0 |
13.2 |
|
Average |
18.1 |
|
2.0 |
12.6 |
|
Max |
20.0 |
|
2.8 |
13.6 |
|
Min |
16.1 |
|
1.0 |
11.0 |
|
Recommended |
16-14 |
|
3.5 |
|
Additional notes
The newly named Midwest Apple Association variety Ludacrisp is testing 20 pounds firmness, starch index 3.0, with brix of 14.8. This variety originated from seed of open pollenated Honeycrisp and has some of the flesh texture of that variety but has a much more complex flavor. Evercrisp, the first release from this program, is still very immature with firmness of 25 pounds, starch index of 1.0, and brix of 12.2.
How to read the maturity tables
For each variety evaluated, each row in the data table is a different orchard block. Maximum and minimum values are the highest and lowest individual fruits evaluated for each. Recommended values are included for each variety at the bottom of the table. These suggested values for firmness and starch index were also published in a standalone table format. Firmness ranges encompass long and short-term storage recommendations.
Firmness in pounds pressure = measured with a FT Penetrometer using a 7/16 inch (11 millimeters) diameter probe, peel removed; range is for the average at each site.
Starch: 1 = no starch conversion, 8 = No starch; range is for average of the sites. Using Cornell Starch Iodine Index Chart.
Brix = % sugar measured with Atago PAL-1 Pocket Refractometer
Additional apple maturity helps
- Considerations for the 2021 harvest season can be found in this article.
- 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.
- 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 |
|
Normal and predicted 2021 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 SW |
2020 Predicted 1st significant harvest date |
2021 Predicted 1st significant harvest date |
|
Paula Red |
22-Aug |
25-Aug |
13-Aug |
|
Zestar |
22-Aug |
25-Aug |
13-Aug |
|
Gingergold |
20-Aug |
23-Aug |
11-Aug |
|
Early Fuji |
3-Sep |
6-Sep |
25-Aug |
|
Gala |
8-Sep |
11-Sep |
31-Aug |
|
McIntosh |
10-Sep |
13-Sep |
1-Sep |
|
Honeycrisp |
13-Sep |
15-Sep |
4-Sep |
|
Empire |
18-Sep |
21-Sep |
21-Sep |
|
Jonathan |
22-Sep |
24-Sep |
25-Sep |
|
Jonagold |
22-Sep |
24-Sep |
25-Sep |
|
Fuji |
25-Sep |
28-Oct |
28-Sep |
|
Golden Delicious |
25-Sep |
27-Sep |
28-Sep |
|
Red Delicious |
28-Sep |
20-Sep |
3-Oct |
|
Ida Red |
5-Oct |
7-Oct |
10-Oct |
|
Rome |
5-Oct |
7-Oct |
10-Oct |
|
Braeburn |
20-Oct |
22-Oct |
25-Oct |
|
Goldrush |
26-Oct |
28-Oct |
27-Oct |
Please note that the 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.