Southwest Michigan apple maturity report – October 16, 2013

Harvest of Golden Delicious and Red Delicious is winding down. Ida Reds have reached sufficient maturity for good quality, long-term storage. Growers are still holding back from Fuji and Braeburn harvest to wait for better skin color.

General comments

This is the last week for the apple maturity report for the southwest region for the season, although other regions may continue with reports for the next week or two.

Summary of Berrien County apple maturity samples taken Oct. 14, 2013

Variety

Firmness lbs. pressure (range)

Starch conversion (range)

Brix (range)

Fuji

17.0 (18.2 – 16.1)

5.7 (4.8 - 7.0)

14.8 (14.2 - 15.0)

Ida Red

15.5 (15.7 - 15.0)

3.7 (3.4 - 3.8)

13.3 (12.8 - 14.1)

Braeburn

20.7 (21.2 - 20.3)

3.9 (2.6 - 6.0)

12.7 (11.7 - 14.0)

Fuji (five sites sampled Oct. 14)

This week’s tests show average firmness of 17 pounds (range 16.1-18.2) compared to 18.0 pounds for last week. Starch conversion this week is up considerably to 5.7 (range 4.8-7.0) compared to 4.6 for last week, and average brix of 14.8 compared to 12.6 for last week. Fuji has reached the fruit conditions for long-term CA, which is fruit firmness of 17 pounds or greater and minimum of 3.0 for the starch conversion index. Slight amounts of watercore are showing up in the flesh.

Predicted harvest date for central Berrien County is Oct. 20. Background skin color is still noticeably green. The continued excellent firmness will allow delay of harvest until skin color, size and brix improves, although starch conversion is sufficient in some sites for successful long-term CA storage.

Ida Red (four sites sampled Oct. 14)

This week’s tests show firmness of 15.5 pounds (range 15.0-15.7), about the same as last week. Starch conversion is 3.7 (3.4-3.8) compared to last week’s 2.8, and brix is 13.3 compared to 12.8 for last week. Predicted harvest date for central Berrien County was Oct. 5. This variety has reached the target for long-term CA of fruit firmness of 15 pounds or greater and minimum of 3.5 for the starch conversion index. Harvest of orchards for shorter-term CA or more immediate processing can be delayed somewhat to wait for better size and greater starch conversion.

Braeburn (five sites sampled Oct. 14)

This week’s tests show firmness of 20.7 pounds (20.3-21.2) compared to 21 pounds for last week. Starch conversion is 3.9 (2.6-6.0) compared to 3.2 pounds for last week, and brix is 12.7 (11.7-14.0), about the same as last week. Predicted harvest date for central Berrien County is Oct. 20. For this variety, the targeted fruit conditions for long-term CA are fruit firmness of 18 pounds or greater and minimum of 3 for the starch conversion index. Background color is generally green. Harvest of orchards similar to these samples can be delayed to wait for better skin color, size and greater starch conversion.

Pressure and starch conversion target indices for apple maturity for selected varieties

Variety

Firmness

Starch

Short CA*

Mid-CA

Long CA

Mature

Over mature

Red Delicious

16

17

18

2.5

5.0

Fuji (main season)

15

16

17

3.0

7.0

Ida Red

14

15

16

3.5

6

Braeburn

16

17

18

3.0

7.0

*CA = controlled atmosphere storage

Looking for more? View Michigan State University Extension’s Apple Maturity Program and Reports resource page for regional reports throughout the state and additional resources.

The Southwest Michigan Apple Maturity Report is produced by: Bill Shane, MSU district Extension educator for fruit and marketing, Benton Harbor, 269-944-1477 ext. 205, fax 269-944-310; Diane Brown, Berrien County Extension educator, Benton Harbor, 269-944-4126; and Mark Longstroth, district Extension educator for fruit and marketing, Paw Paw.

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