CANR RESPONSE TO NOVEL CORONAVIRUS

Southwest Michigan apple maturity report – Sept. 4, 2019

Current mild conditions are helpful for good apple quality and skin coloring.

General apple harvest comments

Cool conditions have delayed apple harvest this season relative to last year and normal. The recent dry weather has generally cooperated with harvesting activity. Area growers are busy picking Zestar, McIntosh, early Fuji and early season Honeycrisp (e.g., Premier). Some spot picking of Gala and Honeycrisp is underway on early ripening sites and sites with light crops.

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.

Oriental fruit moth, codling moth, obliquebanded leafroller, apple maggot and San Jose scale are additional pests of concern at this time of year. Sooty blotch and flyspeck diseases are favored by the warm, wet conditions we have had in recent days. A few apples, especially light colored varieties, are infected by the fungal disease bitter rot, which appears as circular, dark fruit spots with salmon-orange, slimy spores most visible under rainy conditions.

Apple maturity in southwest Michigan for apples harvested Sept. 3, 2019

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Mac

17.0 (17.0-17.0)

3.3 (3.0-3.6)

12.4

Honeycrisp

18.3 (17.0-20.0)

2.5 (1.8-3.8)

12.0

Early Fuji

19.2 (19.0-19.4)

2.5 (3.0-4.0)

12.9

Gala

21.1 (20.0-23.0)

2.7 (1.4-4.4)

10.8

Individual variety results

Note: Blocks with light crops and on sandy soils will generally harvest earlier.

McIntosh

The current starch test average of 3.3 is below the recommended target starch index of 5. A minimum firmness of 16 pounds recommended for long-term controlled atmosphere (CA) storage. Predicted peak harvest date for central Berrien County is Sept. 16. In cool seasons, like 2019, McIntosh tend to harvest earlier than Gala.

Gala

Target starch index for maturity for this variety is 3. The current average is 2.7, but the range is wide, with some blocks testing over the threshold. Relative firmness is averaging 21, with the minimum firmness of 18 pounds recommended for long-term controlled atmosphere (CA) storage. Predicted peak harvest date for central Berrien County is Sept. 14.

Honeycrisp

The current average of 2.5 is below the target mature starch index of 3.5 for this variety. The current average firmness of 18.3 is above the general guideline of 17 pounds for best long-term CA storage. The predicted peak harvest date is Sept. 20 for central Berrien County. Blocks with light crops, common in southwest Michigan this year, will generally harvest earlier than those with normal or heavier crops.

Early Fuji

A starch test of 3 is generally used as the target for mature for this variety, compared to the current average of 2.3. General guideline of 18 pounds for best long-term CA storage, although this variety is generally used for direct fresh sales rather than long term storage. The current average is 19.3 pounds. The predicted peak harvest date is Sept. 10 for central Berrien County.

Normal and predicted 2019 peak harvest dates for apple varieties in central Berrien County 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

2019 Predicted peak harvest date

Paula Red

Aug. 22

 Aug. 20

Aug. 28

Zestar

Aug. 22

 Aug. 20

Aug. 28

Gingergold

Aug. 20

 Aug 18

Aug. 26

McIntosh

Sept. 10

 Sept 8

Sept. 16

Gala

Sept. 8

 Sept 6.

Sept. 14

Early Fuji

Sept. 3

 Sept. 1

Sept. 10

Honeycrisp

Sept. 13

 Sept. 13

Sept. 20

Empire

Sept. 19

 Sept. 23

Sept. 26

Jonathan

Sept. 22

 Sept. 24

Sept. 30

Jonagold

Sept. 22

 Sept. 24

Sept. 30

Golden Delicious

Sept. 25

 Sept. 27

Oct. 1

Red Delicious

Sept. 28

 Oct. 1

Oct. 7

Ida Red

Oct. 5

 Oct. 8

Oct. 15

Rome

Oct. 5

 Oct. 8

Oct. 15

Fuji

Oct. 20

 Oct. 22

Oct. 28

Braeburn

Oct. 20

 Oct. 22

Oct. 28

Goldrush

Oct. 26

 Oct. 28

Nov. 3

 

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.)

 

Did you find this article useful?