Southwest Michigan apple maturity report – September 21, 2022
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EmailA few Honeycrisp remain to be harvested in southwest Michigan. Growers are now switching to harvesting Jonagold, Golden Delicious and Red Delicious.
This is our weekly southwest region apple maturity report. 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:
Sooty blotch is fairly common on fruit of unprotected orchards. Orchards 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.
Distinguishing between stink bug and bitter pit damage on apples is not always easy. Articles from Cornell and MSU can help.
MDARD has a 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 accumulated.
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.
Jonagold
Internal starch conversion is averaging 5.7, well into mature zone, still with acceptable firmness for long storage. The predicted harvest date for central Berrien County is Sept. 21.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 29 |
N/A |
19.4 (18.2-21) |
2 (2-2) |
12 (11.7-12.2) |
|
Sep 6 |
73.4 (50-99) |
18.5 (17-21.3) |
2.3 (2-3.2) |
11.4 (10.8-12) |
|
Sep 12 |
69.8 (30-99) |
17.8 (16.2-20) |
3.7 (2-5.4) |
12.1 (11.5-13.6) |
|
Sep 19 |
74.8 (40-99) |
17.0 (15.5-19) |
5.7 (3.4-7.4) |
12.4 (10.5-14.2) |
Honeycrisp (Main season)
No new samples this week. Crop reached full maturity last week. 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.
Empire
Fruit starch conversion has now reached the mature range (3.5 and above). This is in line with the predicted harvest date for central Berrien County of Sept. 18.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Sep 6 |
59 (45-75) |
18.9 (18-19.4) |
2.4 (2-3) |
11.1 (10.4-11.9) |
|
Sep 12 |
64 (50-85) |
18.6 (17-18.9) |
2.7 (2-3.4) |
11.4 (10.9-12) |
|
Sep 19 |
77 (50-99) |
18 (17.1-18.5) |
3.8 (3.6-5.2) |
11.7 (11-12.9) |
Fuji (Main season)
Fruit background color is still relatively green. Starch conversion is averaging 3.0, borderline mature. Fruit firmness is still relatively high, allowing older Fuji varieties with less color more time. Fuji is highly susceptible to watercore, which becomes more of a problem on fruit harvested past optimum maturity. The predicted harvest date for central Berrien County is Sept. 24.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Sep 6 |
55 (30-65) |
21 (19-24) |
2.4 (2-3) |
11.4 (10.4-12) |
|
Sep 12 |
48 (25-62) |
19.3 (18-20.4) |
2.8 (1.8-3) |
11.4 (10.6-12.1) |
|
Sep 19 |
67 (55-82) |
19 (18-19.8) |
3.0 (2.6-3.8) |
12.1 (11.3-12.8) |
Golden Delicious
Second samples were taken this week. Fruit background color is still relatively green. Starch conversion has moved from an average of 1.9, to 3.1 this week, 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. Storage of this variety is best at 32 – 33 F in air or CA storage. Golden Delicious can lose water relatively rapidly in storage if humidity is low.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Sep 12 |
16.7 (12-30) |
17.1 (16.1-18) |
1.9 (1.2-2.4) |
11.4 (10.5-12.2) |
|
Sep 19 |
14.4 (0-37) |
17.3 (16-18.1) |
3.1 (1.6-5.2) |
12.4 (11.5-13.8) |
Red Delicious
Second samples were taken this week. Starch conversion is averaging 2.4, about the same as last week, with 2.5 as the threshold for mature. Firmness at 18 is about the same as last week, with the threshold of 18 for long-term controlled atmosphere storage. Fruit maturity is somewhat ahead of the predicted harvest date for Red Delicious for central Berrien County of Sept. 29.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Sep 12 |
98 (98-99) |
17.4 (16.4-18) |
2.7 (2-3) |
9.9 (9.3-10.8) |
|
Sep 19 |
94 (80-99) |
18 (16.7-20.4) |
2.4 (2-4) |
9.7 (9-10.7) |
IdaRed
First samples were taken this week. Fruit background color is still relatively green. Starch conversion is averaging 1.8, immature. Firmness is good at an average 18.4. The predicted harvest date for IdaRed for central Berrien County is Oct. 6.
|
Collection Date |
Red Color (%) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Sep 19 |
70.3 (67-72) |
18.4 (17.6-18.8) |
1.8 (1.4-2.0) |
10.8 (10.2-11.7) |
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 based on averages for orchards tested.
- Starch: 1 = all starch, 8 = all starch converted; range is based on averages for orchards tested using Cornell Starch Iodine Index Chart.
- 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 |
|
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.