West central Michigan apple maturity report – October 26, 2022
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EmailAfter a warmup over the weekend, rain set in across the region. For many growers, harvest is wrapping up this week.
Apple maturity testing is wrapping up this week. In the west central region, some growers have finished harvesting fruit for the season. Other growers are working to finish harvesting later varieties such as EverCrisp and Pink lady. Color development and sugar levels have continued to be excellent. This is a short report this week as only EverCrisp were tested for maturity.
Weather over the past week has been warmer than normal and wet. Heavy rainfall occurred across the region, and some areas, and temperatures are slowly decreasing. This weekend, highs will be in the upper 50s Fahrenheit with lows in the 30s F and 40s F. As of Oct. 25, the Enviroweather station for Hart has reported an accumulation of degree days since last week with 3875 DD42 and 2496 DD50.
As fruit harvest continues, growers should consider applying preharvest fungicides to minimize storage rots. As a reminder, with regular rain events, growers should maintain fungicide coverage to minimize late season rots, particularly for fruit that will be in long-term storage. Rainfall over two inches can wash off fungicide residues on fruit. Excessive rain may also have an impact on fruit by temporarily diluting flavor and brix (sugars).
How to read maturity tables
Each week, an apple maturity report will be provided and will include average values for several apple samples for varieties nearing maturity. Maximum and minimum values are included in tables below for the highest and lowest individual fruits evaluated for each, to give a full spectrum of maturity. All samples included in the reports have been untreated with ReTain or Harvista, unless otherwise noted. Samples were collected from two to three locations across Oceana County.
For more information about apple maturity testing, review these resources compiled by Anna Wallis and Amy Irish Brown, MSU Extension.
- 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.
Maturity information for the west central region
Evercrisp
Fruit were sampled from three locations on Oct. 24 in Oceana County. Red color has been consistent over the past few weeks, and background color is turning light yellow. Fruit are generally very firm with an average of 19.9. Starch clearing has advanced to an average rating of 5.6 this week. Penn State University recommends using a starch index of 4-6 for long-term storage and 6-7 for direct sales markets. Sugar levels are excellent for this variety. Similar to its Fuji parentage, watercore was present at all locations samples.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Oct 10 |
261 (269-255) |
68.8 (95-50) |
3. 7 (5-2) |
21.5 (27.4-16.6) |
3.1 (6-2) |
15.8 (18.3-14.4) |
|
Oct 17 |
277.8 (289-263) |
65 (90-45) |
3.5 (5-2) |
20.4 (24.5-15.9) |
4.2 (7-2) |
16.1 (17.9-14.1) |
|
Oct 24 |
279 (318-234) |
70 (90-45) |
2.3 (4-1) |
19.9 (21.9-16.5) |
5.6 (8-4) |
15.6 (16.1-15.1) |
Apple maturity sampling parameters
- Ethylene (% fruits with internal ethylene over 0.2 ppm) = indicates when ethylene begins to influence fruit ripening and it cannot be held back easily after this is reached.
- Color % = the visual percentage of red color from 0 to 100; range is of all fruits tested. Indicates surface area covered in red and intensity of red color.
- Background color: 5 = Green, 1 = Yellow; range is of all fruits tested.
- Firmness in pounds pressure = measured with a Güss Fruit Texture Analyzer; 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: will typically be rated using the standard Cornell SPI scale (1-8). However, a separate starch chart for Honeycrisp Apples developed by Washington State University (scale 1-6) also exists.
- 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 |
|
Brix Guide |
Low |
Fair |
Good |
Excellent |
|
All varieties |
Less than 11 |
11 |
12 |
13 |
|
Honeycrisp |
Less than 12 |
12 |
12 |
Greater than 14 |
|
Brix Guide |
Low |
Fair |
Good |
Excellent |
|
All varieties |
Less than 11 |
11 |
12 |
13 |
|
Honeycrisp |
Less than 12 |
12 |
12 |
Greater than 14 |