Southwest Michigan apple maturity report – Sept. 19, 2018

Area growers are working their way through Honeycrisp and Jonagold apple harvest in southwest Michigan.

September 19, 2018 - Author:

apple bitter rot
A diagnostic feature of apple bitter rot on fruit is their wedge-like appearance when viewed in cross-section. Photo by Melaine Ivey, Ohio State University.

General apple harvest comments

Apple varieties are ripening quickly this year with the warm weather. Apples grown on sandy sites are showing greater fruit drop tendencies this year. Using stop drop sprays (NAA, Retain and Harvista) are warranted on drop prone varieties. The recent dry weather has generally cooperated with harvesting activity.

Please be aware that samples we collect for this report are from the central Berrien County region, targeting more mature fruit on the outside of the tree canopy. Fruit in the interior of the tree will be less advanced than shown here. Sites with heavier soils and greater crop loads will generally be less mature.

Brown marmorated stink bug is damaging fruit in some area orchards, especially orchard sides close to woods, soybean fields, ravines and where natural hosts such as buckthorn, tree of heaven and mulberry have served as food sources. Some gathering of stink bugs on sunny sides of buildings has begun, maybe triggered by cooler nights and harvesting of infested soybean fields.

Oriental fruit moth, codling moth, obliquebanded leafroller, apple maggot and San Jose scale are additional pests of concern at this time of year. San Jose scale trap catches at Trevor Nichols Center in Fennville, Michigan, are up sharply for the start of the third generation flight. A new generation of crawlers are expected approximately 375 degree days base 51 degrees Fahrenheit after this Sept. 17 biofix, estimated to start crawling shortly before the end of September. This generation is difficult to manage in apple orchards this time of year because of the pre-harvest interval restrictions for insecticides.

Sooty blotch and flyspeck diseases are favored by the warm, wet conditions. Apples infected with bitter rot, especially light colored varieties, are showing up in bins. Symptoms of bitter rot are circular, dark fruit spots with salmon-orange, slimy spores most visible under rainy conditions. Fruit cut in cross section show a wedge-like dark area, tapering toward the core.

Apple maturity in southwest Michigan for apples harvested Sept. 17

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Gala

18.4 (18.0-19.0)

6.8 (6.4-7.0)

14.8

Honeycrisp

15.6 (14.0-17.0)

6.2 (5.0-7.0)

12.0

Jonagold

18.4 (17.0-20.0)

4.8 (3.4-6.0)

12.1

Empire

18.7 (18.0-21.0)

2.8 (2.0-3.2)

11.9

Golden

18.5 (17.0-19.4)

3.1 (2.2-5.0)

12.0

Red Delicious

18.0 (17.0-20.0)

2.9 (2.4-3.6)

10.1

IdaRed

19.5 (19.0-20.0)

1.5 (1.0-2.0)

11.1

Individual variety results

Gala was sampled for the fourth week and this will be the final week for this variety. Most Galas have been picked in the area. This variety tests mature at all locations. Starch readings moved from 5.4 last week to 6.8 this week. Predicted peak harvest date for central Berrien County is Sept. 10.

Gala maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Aug. 28

25.4 ( 22.0-28.0)

1.5 (1.4-1.6)

11.8

Sept. 4

23.0 (21.3-25.0)

3.3 (1.8-4.6)

11.8

Sept. 11

20.0 (22.0-17.0)

5.4 (4.4-7.0)

12.6

Sept. 17

18.4 (18.0-19.0)

6.8 (6.4-7.0)

14.8

Honeycrisp was sampled for the fourth week and continues to show rapid maturation. Starch conversion moved from an average of 5.3 last week to 6.2 for this week, all sites testing above the target mature starch index of 3.5 for this variety. The predicted peak harvest date is Sept. 18 for central Berrien County, so this variety matured ahead of the predicted date. This variety has shown considerable pre-harvest fruit drop this year especially on sandy sites.

Fruit firmness is averaging 15.6 pounds this week, about the same as last week, with the general recommendation for a minimum 17 pounds firmness for best long-term and minimum of 16 pounds for mid-term (duration) controlled atmosphere storage.

Honeycrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Aug. 28

20.0 (17.0-23.1)

1.8 (1.6-1.8)

12.0

Sept. 4

17.7 (16.2-19.0)

2.9 (1.6-4.8)

11.6

Sept. 11

15.9 (15.0-17.0)

5.3 (4.2-7.0)

12.3

Sept. 17

15.6 (14.0-17.0)

6.2 (5.0-7.0)

12.0

Jonagold was sampled this week for the second time this season. Starch conversion is averaging 4.8, a jump from 2.3 last week, with 3.5 as the target for mature for this variety. The predicted peak harvest date is Sept. 24 for central Berrien County, which seems to indicate this variety is maturing slightly ahead of prediction. Brix for this week is 12.1.

Fruit firmness averaged 18.4 pounds this week, with the general guideline of a minimum of 17 pounds firmness for best long-term CA storage. The starch test indicates fruit tested were mature, with newer red strains having sufficient color for fresh market.

Jonagold maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 11

19.5 (18.0-21.0)

2.3 (1.2-3.6)

11.4

Sept. 17

18.4 (17.0-20.0)

4.8 (3.4-6.0)

12.1

Empire was sampled for the second week. Starch conversion is averaging 2.8 this week, with 3.5 as the target for mature for this variety. The predicted peak harvest date is Sept. 23 for central Berrien County. Brix for this week is 11.9.

Fruit firmness averaged 18.7 pounds this week, about the same as last week with the general guideline of a minimum of 16 pounds firmness for best long-term CA storage. Based on these tests, harvest for fresh market can be delayed to wait for better size and quality.

Empire maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 11

18.5 (18-20)

2.1 (1.8-2.6)

11.2

Sept. 17

18.7 (18.0-21.0)

2.8 (2.0-3.2)

11.9

Golden Delicious was sampled for the second week. Starch conversion jumped this week, reading 3.1 compared to an average of 1.5 for last week, with 3 as the target for mature for this variety. The predicted peak harvest date is Sept. 27 for central Berrien County.

Brix for this week is 12.0. Fruit firmness averaged 18.5 pounds this week, about the same as last week with the general guideline of a minimum of 17 pounds for best long-term CA storage. As seems to be the case this year, this variety should be watched carefully as apples seem to be ripening before the predicted harvest date.

Golden Delicious maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Sept. 11

18.2 (16-20)

1.5 (1.0-2.4)

11.1

Sept. 17

18.5 (17.0-19.4)

3.1 (2.2-5.0)

12.0

Red Delicious was tested for the first time this week. Starch conversion is averaging 2.9 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 10.1. Fruit firmness averaged 18 pounds this week, with the general guideline of 18 pounds for best long-term CA storage. Red skin color has improved greatly over the past week. Based on these tests some spot picking of more advanced maturity orchards could begin.

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

IdaRed were tested for a few area orchards this week. Starch conversion is averaging 1.5 this week, with 3.5 as the minimum for mature for this variety. The predicted peak harvest date is Oct. 8 for central Berrien County.

Brix for this week is 11.1. Fruit firmness averaged 19.5 pounds this week, with the general guideline of a minimum of 16 pounds for best long-term CA storage. This variety has a ways to go before it is ready for picking.

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

For additional comments from Randy Beaudry, MSU Department of Horticulture, read his general observations from MSU Apple Maturity Lab for 2018.

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

Fuji

16

17

18

3

7

Rome

15

16

18

3

5.5

*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.

Tags: apple harvest 2018, apple maturity reports, msu extension, southwest apple maturity report


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