West central Michigan apple maturity report – October 2, 2024
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EmailIdared and Ambrosia are being harvested in the west central region this week. With cooler temperatures, it is finally beginning to feel like fall.
In the west central region, Golden Delicious, Red Delicious, Ambrosia, Mutsu and Idared have been harvested at some locations. Some growers will be harvesting Mutsu and Northern Spy this week. Aztec Fuji, EverCrisp and Pink Lady will be ready for harvest over the next one to two weeks (Figure 1).
Weather over the past week has been warmer than normal with a drop in temperature on Oct. 1, which is normal for this time of year. Fall weather is setting in. High temperatures will remain in the 60s and 70s over the next week with lows in the 40s and 50s which is good coloring weather. Chances of rain are low over then next week, and soil conditions continue to be dry.
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 a
re 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 reorts have been untreated with ReTain or Harvista, unless otherwise noted. Samples were collected from two to five locations across Oceana County (Figures 2-3). 
For more information about apple maturity testing, review these resources compiled by the Michigan State University Extension tree fruit team.
- Predicted apple harvest dates for 2024 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.
- New starch charts for evaluating apple maturity in Michigan from Michigan State University
- 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
Mutsu/Crispin
Fruit were sampled at one location in Oceana County this week. Fruit are mature, and there is some blush. Background color is light green, and firmness decreased to 16.9 lbs pressure. Starch is 3.3. Some watercore was observed this week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|
|
Sept 9 |
301 (343-259) |
25 (45-2) |
4.8 (5-4) |
18.6 (21.5-16.1) |
1.9 (3-1) |
11.3 (11.5-11.1) |
|
Sept 16 |
328 (346-311) |
31 (50-0) |
4.7 (5-4) |
18.8 (21.1-17.0) |
2.2 (7-1) |
12.3 (12.9-11.7) |
|
Sept 23 |
368 (373-364) |
30 (50-0) |
4.2 (5-3) |
19.4 (23.3-16.1) |
2.0 (3-1) |
13.2 (13.8-12.6) |
|
Sept 30 |
391.5 |
14 (35-0) |
3.3 (4-3) |
16.9 (18.4-14.9) |
3.3 (5-2) |
12.4 |
Idared
Fruit were sampled at four locations in Oceana County this week, and some blocks have been harvested already. Fruit are mature, and red color development is similar to last week. Background color is yellow green, and firmness decreased to 15.1 lbs pressure. Pressure recommended for long-term storage is 16 lbs, and fruit are considered mature with a starch rating of 3.5. Starch is rated at 4.4. Sugars are similar to last week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|
|
Sept 16 |
197 (260-167) |
75 (99-50) |
3.7 (4-3) |
18.4 (21.6-14.3) |
1.9 (3-1) |
11.4 (12.4-10.6) |
|
Sept 23 |
191 (240-162) |
86 (99-50) |
3.5 (4-1) |
17.4 (20.6-13.2) |
2.6 (4-1) |
12.6 (13.7-11.8) |
|
Sept 30 |
211 (318-158) |
80 (95-60) |
2.5 (4-1) |
15.1 (19.2-12.1) |
4.4 (7-2) |
12.6 (12.9-12.3) |
Aztec Fuji
Fruit were sampled at three locations in Oceana County this week. Fruit are mature and can be harvested for long- or mid-term storage. Red color development is similar to last week, and background color is light green. Firmness is 16.5 lbs pressure, and 17 lbs of pressure is the target pressure for mid-term storage. Starch is 3.7, and sugar is excellent at 13.0 Brix.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|
|
Sept 23 |
205 (231-188) |
83 (99-60) |
4.1 (5-3) |
17.5 (19.3-16.1) |
2.5 (4-2) |
13.1 (14.0-12.6) |
|
Sept 30 |
210 (243-177) |
76.2 (95-55) |
2.9 (4-2) |
16.5 (20.2-12.5) |
3.7 (5-2) |
13.0 (13.8-12.1) |
EverCrisp
Fruit were sampled at five locations in Oceana County this week. Fruit immature, but they are more mature than expected and ahead of normal this year. Fruit may be mature and ready for harvest next week for long- or mid-term storage. Red color development is 58%, and background color is green. Fruit are very firm, and firmness is 21.4 lbs pressure. Starch is 2.9, and sugar is excellent at 15.1 Brix.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|
|
Sept 30 |
237 (264-213) |
58 (85-40) |
3.16 (4-2) |
21.4 (27.4-17.3) |
2.9 (7-1) |
15.1 (17.4-13.3) |
Pink Lady
Fruit were sampled at two locations in Oceana County this week. Fruit are immature. A pink blush is developing on the fruit and was observed at 43%. Background color is green. Fruit are very firm, and firmness is 20.6 lbs pressure. Starch is 1.9, and sugar is excellent at 13.0 Brix.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|---|---|---|---|---|---|---|
|
Sept 30 |
191 (195-186) |
43 (55-35) |
3.1 (4-3) |
20.6 (25.1-17.3) |
1.9 (4-1) |
13 (13.7-12.3) |
Apple maturity sampling parameters
- 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 for Honeycrisp: will typically be rated using the standard Michigan State University starch 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 |