Southwest Michigan apple maturity report – Oct. 10, 2018

Red Delicious and Golden Delicious harvest is still ongoing in southwest Michigan.

Nectria blight on apple limb
Apple limb affected by the fungal disease Nectria blight. Orange spore masses are a key diagnostic feature. Photo by Bill Shane, MSU Extension.

General apple harvest comments

Rains over the past two weeks have slowed harvesting somewhat in southwest Michigan, with more problems in orchards with heavier soils. Orchards in the northern part of the region have been wetter. Red Delicious and some Golden Delicious continue to be the focus for many growers this week. IdaRed harvest is nearly done. Growers will be turning their attention to Fuji and Braeburn.

Some Rome blocks are showing Nectria blight symptoms in which current seasons growth on ends of limbs wilt and turn brown, much like fire blight. Branches affected by this fungal disease may have clusters of pink to orange spores at the base of the wilted areas, and, unlike fire blight, generally do not ooze.

Sooty blotch and flyspeck symptoms on fruit are problems in some orchards, especially next to woods. Some growers report problems with fruit rots associated with insect punctures. Bitter pit is showing up on some Honeycrisp fruit coming out of storage.

Brown marmorated stink bug activity jumped up over the past week when temperatures reached into the 80s. Damage to apple fruit late in the season may be overlooked, but show up later in storage. Scouting for insect activity, especially on orchard borders, should be done during sunny, calm times when the pest tends to be most active. Other stink bug species and lady beetles are very active.

Apple maturity in southwest Michigan for apples harvested Oct. 8

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Red Delicious

16.4 (15.4-17.8)

4.6 (4.0-5.6)

11.5

IdaRed

16.5 (15.2-18.1)

3.5 (2.4-4.2)

11.4

Fuji

18.4 (17.4-20.3)

5.1 (4.2-7.0)

13.5

Rome

21.8 (21.4-22.3)

3.2 (3.0-3.6)

10.9

Braeburn

21.5 (20.0-23.0)

3.8 (2.8-4.6)

11.0

Evercrisp

23.4 (23.1-23.7)

4.1 (3.0-5.0)

15.8

Individual variety results

Red Delicious was tested for the fourth week. Starch conversion is averaging 4.6 this week with 2.5 as the minimum for considering to be mature for this variety. The predicted peak harvest date is Oct. 1 for central Berrien County.

Brix for this week is 11.5. Fruit firmness averaged 16.4 pounds this week, only slightly less than last week with the general guideline of 18 or more pounds firmness is best for long duration and 17 pounds for mid-duration controlled atmosphere (CA) storage. Skin color is generally excellent.

Red Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

18.0 (17.0-20.0)

2.9 (2.4-3.6)

10.1

Sept. 24

17.3 (16.0-18.3)

3.5 (3.0-4.0)

10.3

Oct. 1

16.6 (15.2-17.9)

4.0 (3.0-5.6)

10.8

Oct. 8

16.4 (15.4-17.8)

4.6 (4.0-5.6)

11.5

IdaRed were tested for the fourth week in southwest Michigan orchards. Starch conversion is averaging 3.5 compared to 2.7 for last week, with at least 3.5 considered mature for this variety. Brix for this week is 11.4, nearly the same as last week. Fruit firmness averaged 17.3 pounds, slightly less than last week. The general guideline is a minimum of 16 pounds firmness for best long-term CA storage. Most IdaRed orchards in the lower southwest region have been picked. Fruit maturation has been close to or slightly ahead of the predicted peak harvest date of Oct. 8 for central Berrien County.

IdaRed maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 17

19.5 (19.0-20.0)

1.5 (1.0-2.0)

11.1

Sept. 24

17.9 (17.0-19.8)

2.1 (1.8-2.6)

10.9

Oct. 1

17.3 (16.2-18.4)

2.7 (2.2-3.0)

11.4

Oct. 8

16.5 (15.2-18.1)

3.5 (2.4-4.2)

11.4

Fuji were tested for the third week. Starch conversion is averaging 5.1, which is a big jump from last week, with 3.0 given as the minimum for mature for this variety. Fruit firmness averaged 18.4 pounds this week, with the general guideline of a minimum of 18 pounds for best long-term CA storage. Background coloration is improving and internal maturity is relatively advanced, and appears to be ahead of the predicted peak harvest date of Oct. 22 for central Berrien County. Brix for this week is 13.5 percent.

Fuji maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 24

19.5 (17.5-20.4)

3.4 (2.8-3.8)

12.0

Oct. 1

19.0 (17.1-20.3)

3.6 (3.4-4.0)

12.5

Oct. 8

18.4 (17.4-20.3)

5.1 (4.2-7.0)

13.5

Rome were tested for the second time this season. Starch conversion is averaging 3.2 this week, with 3.0 as the minimum for mature for this variety. Brix for this week is 12.0. Fruit firmness averaged 21.8 compared to 23.7 pounds for last week, with the general guideline of a minimum of 18 pounds for best long-term CA storage. Background coloration is still relatively green. The predicted peak harvest date is Oct. 8 for central Berrien County.

Rome maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 1

23.7 (22.9-24.4)

3.0 (2.8-3.2)

10.7

Oct. 8

21.8 (21.4-22.3)

3.2 (3.0-3.6)

10.9

Braeburn were tested for the second week and this variety is showing a marked jump in ripening activity. Starch conversion is averaging 3.8 compared to 2.7 for last week, with 3.0 as the recommended minimum value to be considered mature for this variety. Brix for this week is 11.0, same as last week. Fruit firmness averaged 21.5 pounds this week, about the same as last week, with the general guideline of a minimum of 18 pounds for best long-term CA storage. Background coloration is still relatively green, with a predicted peak harvest date of Oct. 22 for central Berrien County.

Braeburn maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 1

22.1 (20.2-23.5)

2.7 (1.0-4.2)

11.0

Oct. 8

21.5 (20.0-23.0)

3.8 (2.8-4.6)

11.0

Evercrisp were tested for the first time this week. Starch conversion is averaging 4.1 this week, with 3.0 as the minimum for mature for this variety. Evercrisp is a Fuji X Honeycrisp cross and shows characteristics of both parents. Like Fuji, red skin blush is improved as trees mature, and is enhanced by proper fruit thinning, and pruning to promote light exposure.

Brix for this week is 15.8. Fruit firmness averaged 23.4 pounds this week, with the general guideline of a minimum of 18 pounds for best longterm CA storage.

Evercrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 8

23.4 (23.1-23.7)

4.1 (3.0-5.0)

15.8

 

Normal and predicted 2018 peak harvest dates for apple varieties in southwest Michigan based on weather data at the Southwest Michigan Research and Extension Center, Benton Harbor, MI.

Variety

Normal date

2018 Predicted peak harvest date

Paula Red

Aug. 22

 Aug. 20

Zestar

Aug. 22

 Aug. 20

Gingergold

Aug. 20

 Aug 18

McIntosh

Sept. 10

 Sept 8

Gala

Sept. 8

 Sept 6.

Early Fuji

Sept. 3

 Sept. 1

Honeycrisp

Sept. 13

 Sept. 13

Empire

Sept. 19

 Sept. 23

Jonathan

Sept. 22

 Sept. 24

Jonagold

Sept. 22

 Sept. 24

Golden Delicious

Sept. 25

 Sept. 27

Red Delicious

Sept. 28

 Oct. 1

Ida Red

Oct. 5

 Oct. 8

Rome

Oct. 5

 Oct. 8

Fuji

Oct. 20

 Oct. 22

Braeburn

Oct. 20

 Oct. 22

Goldrush

Oct. 26

 Oct. 28

 

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

7

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

Crispin / Mutsu

16

17

18

3

6

Fuji

16

17

18

3

7

Evercrisp

16

17

18

3

7

Rome

15

16

18

3

5.5

Braeburn

16

17

18

3

7

*Firmness is measured with a mechanical 11-millimeter wide probe inserted into the pared flesh of a fruit to a distance of 8 millimeters. Starch index is measured on equatorial cross section of an apple stained with iodine solution and rated using the Cornell University starch-iodine index chart for apples on a 1-8 scale (Predicting Harvest Date Window for Apples by Blanpied and Silsbey, Cornell Extension Bulletin 221.)

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


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