Southwest Michigan apple maturity report – October 9, 2013

Golden and Red Delicious harvest is proceeding rapidly. Growers are holding back from main season Fuji and Braeburn harvest to wait for better skin color. Other fresh market apples being picked are last of Jonagold, Northern Spy, Rome and Cameo.

General comments

Recent rains have favored sooty blotch and flyspeck infections. The growth of these fungi is favored by temperatures between 65 and 80 degrees Fahrenheit and wet, humid conditions. It usually takes 20 to 25 days for colonies of sooty blotch to appear on fruit after infection occurs and three to six weeks for flyspeck. Lots of stink bugs in orchards with broadleaf weeds, but all the ones we have examined have been the native species and not the marmorated stink bug. Next week will be the last apple maturity report for southwest Michigan for the season.

Summary of Berrien County apple maturity samples taken Oct. 7, 2013

Variety

Firmness lb. pressure (range)

Starch conversion (range)

Brix (range)

Red Delicious

16.7 (17.1 - 16.1)

3.8 (3.2 - 4.4)

12.3 (11.1 - 13.1)

Fuji

18.0 (19.1 - 17.4)

4.6 (3.4 - 6.0)

14.2 (13.4 - 14.9)

Ida Red

15.5 (15.5 - 15.4)

2.8 (2.6 - 3.0)

12.8 (12.4 - 13.1)

Braeburn

21.0 (20.0 - 13.9)

3.2 (2.0 - 6.4)

12.6 (11.4 - 14.4)

Red Delicious (six sites sampled Oct. 7)

This week’s tests show firmness of 16.7 (range 17.1 to 16.1) with 17.2 pounds for last week, starch conversion 3.8 (range 3.2 to 4.4) with 2.9 last week, and brix 12.3 (range 11.1 to 13.1) with 11.6 for last week. Predicted harvest date for central Berrien County was Oct. 3, 2013. For this variety, the target fruit conditions for long-term CA is fruit firmness of 18 pounds or greater and minimum of 2.5 for the starch conversion index. Six of six sites tested had the more advanced fruit in the orchards testing starch conversion in the mature category with firmness adequate for short to mid-range duration CA storage.

Fuji (five sites sampled Oct. 7)

This week’s tests show firmness of 18.0 (range 19.1 to 17.4) compared to 18.6 pounds for last week, starch conversion 4.6 (range 3.4 to 6.0) compared to 3.8 last week, and brix 14.2 compared to 13.3 last week. For this variety, the target fruit conditions for long-term CA is fruit firmness of 17 pounds or greater and minimum of 3.0 for the starch conversion index. Predicted harvest date for central Berrien County is Oct. 20, 2013. Fruit quality is improving. 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 harvest. Background skin color of Fuji apples is generally green.

Ida Red (two sites sampled Oct. 7)

This week’s tests show firmness of 15.5 (range 15.5 to 15.4) compared to 16.5 last week, starch conversion 2.8 (range 2.6 to 3.0) compared to 2.6 last week, and brix 12.8 compared to 12.5 last week. Predicted harvest date for central Berrien County was Oct. 5, 2013. For this variety, the target fruit conditions for long-term CA is fruit firmness of 15 pounds or greater and minimum of 3.5 for the starch conversion index. Harvest of orchards similar to these samples can be delayed somewhat to wait for better size and greater starch conversion, although firmness of 15.5 pounds is close to the target of 15 pounds.

Braeburn (five sites sampled Oct. 7)

This week’s tests show firmness of 21 (range 22 to 20), starch conversion 3.2 (range 2.0 to 6.4), and brix 12.6 (range 11.4 to 14.4). Predicted harvest date for central Berrien County is Oct. 20, 2013. For this variety, the target fruit conditions for long-term CA is 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 (man 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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