West central Michigan apple maturity report – August 21, 2024
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EmailEarly apple varieties are being harvested this week in the West Central region and cooler nighttime temperatures will enhance red color development.
This is the first apple maturity report for 2024. Regional reports throughout the state and additional resources can be found at the Michigan State University Extension’s Apple Maturity page.
Apple maturity testing will occur weekly for the West Central region beginning now through the end of harvest. Reports will be sent out every week, following the MSU Fruit Team apple maturity calls on Wednesday mornings.
In the West Central region, early apple varieties of Zestar, Wildfire Gala and Premier Honeycrisp are being harvested this week. First pick Minneiska could be harvested later this week and early next week. September Wonder Fuji, Honeycrisp and Brookfield and Pacific strains of Gala are still immature.
Weather
Weather over the past few days has been cooler than normal with low temperatures dipping down into the 40s across the region. Day and nighttime temperatures will gradually increase through the week and into the weekend with highs in the low to mid 80s and low temperatures in the 60s. Conditions are expected to be dry with slight chances of rain early next week.
Expect moderate conditions going into next week with highs in the 70s and lows in the mid to low 50s. Cool nighttime temperatures will enhance red color development, which is needed, especially for early apple varieties.
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 2-4 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 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
Premier Honeycrisp
Fruit were sampled from three locations on Aug 19 in Oceana County. Individual samples represent fruit closest to maturity or ‘first pick’ fruit in each block. Red color development increased from last week to 76%. Background color is yellow green to yellow. Starch rating is 4.6. For Honeycrisp, the starch rating to indicate maturity is 3.5. Pressure decreased from last week with an average of 13.7 lbs., so fruit are softening. Brix increased slightly from last week.
A note about Premier Honeycrisp: Wait for acceptable varietal flavor and color to develop before picking. Picking fruit and getting it into the market early seems like an edge but will hurt repeat sales of this strain and standard Honeycrisp.
Bitter pit development on fruit has been observed in some locations. Fruit that are high risk or are more susceptible to bitter pit development may be in blocks with younger trees, high-risk rootstocks, high-vigor trees, or low crop loads. Large fruit are also more susceptible to bitter pit development than small fruit. High bitter pit-risk fruit should be cooled quickly to the recommended 38 degrees Fahrenheit storage temperature, as conditioning will exacerbate bitter pit. High risk fruit should be marketed as soon as possible. Fruit intended for longer storage should be pre-conditioned, with recommended conditions of 50 F (room temperature) for 5-7 days.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 12-15 |
214 (240-191) |
67 (99-30) |
4 (5-2) |
15.2 (17.1-11.6) |
3 (8-1) |
11 (12-10.5) |
|
Aug 19 |
221 (243-185) |
76 (99-30) |
3.1 (5-2) |
13.7 (15.5-11.1) |
4.6 (8-1) |
11.7 (12.3-11) |
Ruby Mac
Fruit were harvested from two locations in Oceana County. Ruby Mac is a red coloring strain of McIntosh and is at a similar stage of maturity to standard strains of McIntosh in the area. Fruit are dark red. Background color and red color are similar to last week. Average firmness is lightly lower than last week at 17.5 lbs. Recommended pressure for long-term CA is 16 lbs. Fruit is still immature at starch rating of 2.3. McIntosh are mature at a starch test of 5. Sugar levels are fair at this stage with °Brix is 11.2, similar to last week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 12-14 |
145 (166-128) |
89 (100-45) |
4.9 (5-4) |
17.5 (20.1-15.4) |
2.1 (3-1) |
11.3 (12.0-10.3) |
|
Aug 19 |
152 (168-139) |
92 (99-60) |
4.7 (5-3) |
15.9 (18.8-14.1) |
2.3 (4-1) |
11.2 (11.5-10.6) |
Gala
Gala were sampled from six locations in Oceana County this week. Samples in the table below are for Brookfield and Pacific Gala. Red color improved from last week, and background color is dark yellow. Fruit firmness decreased from last week to an average of 17.3 lbs. of pressure. Starch is similar to last week and beginning to clear. Sugars are an average of 9.8 °Brix.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 12 |
132 (142-123) |
81 (99-30) |
3.3 (5-2) |
22.4 (25.6-17.3) |
1.1 (2-1) |
9.3 (9.8-9.0) |
|
Aug 19 |
150 (175-133) |
92 (100-50) |
2.8 (5-1) |
17.3 (23.6-17.8) |
1.2 (2-1) |
9.8 (10.5-9.2) |
September Wonder Fuji
Fruit were sampled at four locations in Oceana County this week. Fruit are still immature. Red color development is improving at 60% compared to last week. Background color is green. Starch is starting to clear with a rating of 2.3, and sugars are low at this time at 10.1 °Brix.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 12-15 |
141 (154-129) |
52 (70-40) |
4.6 (5-3) |
18.3 (21-15.8) |
1.6 (3-1) |
9.9 (10.5-8.7) |
|
Aug 19 |
144 (160-133) |
60.2 (98-40) |
4.5 (5-3) |
17.2 (21-15.3) |
2.3 (8-1) |
10.1 (11.8-9.1) |
Minneiska
Minneiska fruit were sampled at three locations on Aug 19 and 20 in Oceana County. Red color development improved by 20% from last week. Background color is light yellow. Starch is clearing into the cortex, and sugar levels are at 12.1 °Brix. Some growers will be harvesting this variety later this week.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 12-15 |
178 (192-156) |
64 (90-45) |
2.9 (4-2) |
16.2 (18.9-13.4) |
2.7 (5-1) |
11.8 (12.9-11.4) |
|
Aug 19 |
181 (185-178) |
85 (99-45) |
1.5 (3-1) |
16.3 (19-13.5) |
3.4 (6-2) |
12.1 (13.1-11.5) |
Honeycrisp
Fruit were sampled from three locations on Aug 19 in Oceana County. Red color is 76%. Red color and size will continue to improve over the next few days following cooler daytime temperatures and cool nights in the 40s. Background color is green and fruit are still immature. Pressure is 19.5 lbs., and starch rating averaged at 1.4. Sugars are 11 °Brix.
|
Collection Date |
Fruit Weight (g) |
Red Color (%) |
Background color (5-1) |
Firmness (lbs) |
Starch (1-8) |
Soluble Solids (°Brix) |
|
Aug 19 |
181 (192-175) |
76 (98-55) |
3.6 (5-2) |
19.5 (22.4-17) |
1.4 (4-1) |
11 (11.6-10.1) |
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 |