West central Michigan apple maturity report – October 18, 2023
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EmailFall colors are vibrant and apple harvest continues. Growers are harvesting Idared, Mutsu, Fuji, and EverCrisp this week.
This will be the last west central apple maturity report for 2023. Regional reports throughout the state and additional resources can be found at the Michigan State University Extension’s Apple Maturity page.
In the west central region, growers are harvesting Idared, Mutsu, and Fuji. EverCrisp and Pink Lady are also mature and could be harvested for long-term storage. EverCrisp and Pink Lady are still very firm, and sugars are excellent. Some growers are applying ReTain or Harvista to manage harvest crews. Crop loads are high this season, and crews are working diligently to harvest.
Weather update
The weather over the past week has been cool and rainy. High temperatures have been in the 50s degrees Fahrenheit with lows in the 30s F and 40s F. In Hart, temperatures dipped down into the 30s F across the region on Oct. 16. Also, about 1.5 inches of rain fell over the past week. Sugar levels continue to be good or excellent across varieties. There is a high level of variability in fruit maturity within trees and across blocks this season. Testing fruit maturity for individual blocks is important this year to identify best harvest timing.
As of Oct. 17, the Enviroweather station for Hart has reported an accumulation of 3,883 growing degree days (GDD) base 42 and 2,512 GDD base 50. Temperatures will remain cool over the next few weeks with highs in the 50s F and lows in the 40s F or upper 30s F.
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 three to five locations across Oceana County.
For more information about apple maturity testing, review these resources compiled by the MSU Extension tree fruit team.
- Predicted apple harvest dates for 2023 from MSU Extension.
- More information on harvest management tools and timings can be found in this article.
- 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.
Maturity information for the west central region
EverCrisp
Fruit were sampled from four locations on Oct. 16 in Oceana County. Red color development is improving at 87%. Background color is much more yellow than last week. Fruit firmness is similar to last week at 21.5 pounds. Starch clearing is also similar to last week, and sugar levels decreased slightly. This may be due to recent rainfall. Watercore was observed at all locations sampled this week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Oct. 3 |
238 (273-193) |
65 (95-50) |
4.0 (5-3) |
21.4 (25.2-19.3) |
3.6 (6-1) |
15.7 (16.8-14.2) |
|
Oct. 9 |
267 (295-252) |
74 (90-50) |
3.6 (5-3) |
21.0 (24.0-18.3) |
3.2 (7-1) |
16.9 (17.6-16.0) |
|
Oct. 16 |
252 (286-210) |
87 (99-60) |
2.8 (4-1) |
21.5 (24.3-18.8) |
3.4 (7-2) |
15.9 (17.0-14.8) |
Pink Lady
Fruit were sampled from four locations on Oct. 16 in Oceana County. Pink color development has improved with an average of 82% on the fruit surface. Background color is yellow green, and fruit firmness is variable across locations with an average firmness of 18.4 pounds. Starch clearing is similar to last week, and the average rating is 3.7. Sugar levels are excellent according to the Brix table below.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (Brix) |
|
Oct. 9 |
200 (230-170) |
60 (85-40) |
3.0 (4-2) |
17.9 (22.3-14.9) |
3.7 (5-1) |
14.7 (15.0-14.4) |
|
Oct. 16 |
177 (226-138) |
82 (99-30) |
2.5 (4-1) |
18.4 (25.8-15.4) |
3.7 (7-1) |
15.0 (15.3-14.7) |
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 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 |