MSU Extension Apples

In the west central Michigan region, harvest of Gala, Honeycrisp and September Wonder Fuji is underway. Jonagold and Empire were tested again for maturity this week. Jonagold is mature (Figure 1) and Empire is almost mature at the sites tested. In addition, Mutsu/Crispin, Golden Delicious and Red Delicious were tested this week.

Weather over the past few days has been mixed with cool temperatures over the weekend and excellent coloring conditions. Temperatures will warm up over the next few days. High temperatures will be in the upper 80s through the end of the week and will remain in the 80s through next week. There is little rain in the forecast so conditions will be hot and dry over the next week. This may impact maturity and enhance ripening more rapidly. Bearing trees may also become stressed and need irrigation over the next week to support the apple crop.

Apple harvest continues to move along rapidly and earlier than normal. As growers work through harvest of varieties such as Honeycrisp and Gala and the next varieties start to mature, application of harvest management products like ReTain or Harvista may be needed to help manage harvest timing. These tools may be critical this year as fruit are ripening sooner than normal and may ripen faster with warm weather over the coming week.

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 (Figure 2).

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

Jonagold

Fruit were harvested from three locations in Oceana County. Fruit have developed excellent red color with an average of 95% red color. Background color is yellow green, and fruit have an average pressure of 16.9 lbs. Pressure has held fairly well compared to last week. Recommended pressure for long-term controlled atmosphere (CA) storage is 17 lbs. Fruit is mature with a starch rating of 3.4. Sugar levels have improved with 12.3 Brix.

Empire

Fruit were sampled at two locations in Oceana County this week. Fruit are close maturity and will be harvested at some locations later this week. Red color development improved to 87%. Background color is yellow green, and firmness is 16.6 lbs pressure which is similar to last week. Pressure recommended for long-term storage is 16 lbs. Starch is 2.5 and sugars are 10.5 Brix.

Rome

Fruit were sampled at two locations in Oceana County this week. Fruit are immature but are starting to show early signs of maturation. Fruit are dark red with percent coverage at 96%. Fruit are very firm at 25.5 lbs pressure. Starch is 1.8 and sugars are 10.5 Brix.

Mutsu/Crispin

Fruit were sampled at two locations in Oceana County this week. Fruit are immature. There is some blush although fruit are still green. Background color is green, and firmness is 18.6 lbs pressure. Starch is 1.9, and sugars are 11.3 Brix.

Golden Delicious

Fruit were sampled at three locations in Oceana County this week. Fruit are immature, but early signs of maturity were observed this week. Fruit are still green, and some blush was observed this week. Firmness is 18 lbs pressure, and recommended pressure for long-term storage is 17. Starch is 1.7, and sugars are good at 12.5 Brix according to the table below.

Red Delicious

Fruit were sampled at three locations in Oceana County this week. Fruit are immature and seem to be smaller in size than previous years. Red color development is at 98%. Background color is green, and firmness is 18.2 lbs pressure. Pressure recommended for long-term storage is 18 lbs. Starch is 1.4, and sugars are 10 Brix.

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.