Northwest Michigan apple maturity report – Aug. 31, 2017

Early apple varieties are being harvested. Apple quality is looking pretty good.

General apple harvest comments

Growers of early apple varieties have started harvest in the northwest Michigan region. Overall, apple quality is looking pretty good. This season’s rainfall has helped fruit size, although some blocks with heavier fruit set have smaller fruit. Recent temperatures have been cool in the evenings, which has been promising for nice coloring on apples this season. Some isolated areas have visible frost scars, and scarring from leafroller feeding and plum curculio oviposition that occurred earlier in the season.

During the first week of August, orchards in the East Leland area received hail and hail damaged fruit are noticeable. Apple maggot activity was alarmingly high during the first two weeks of their emergence, but recent apple maggot activity has winded down dramatically and growers are putting on their last sprays for this pest.

We have not detected brown marmorated stink bug in our northwest Michigan trapline and we have not received reports of this pest in the region yet this season. Growers have been extra cautious about San Jose scale management this season, as we observed scale damaged fruit last season; crawler activity is likely ongoing at this time.

Predicted harvest dates are a few days ahead of normal for this season and we will continue to monitor apple maturity to assist growers with harvest decisions in the coming weeks. This is the first 2018 apple maturity report for northwest Michigan and these data show that most apple varieties are not quite ready for picking. We will have more rigorous apple maturity testing in the coming weeks.

Apple maturity in southwest Michigan for apples harvested Aug. 29

Variety

Firmness lbs. (range)

Starch (range)

Brix %

Gingergold

19.7

1

11.8

Redfree

22.9

1

10.7

McIntosh

18.6 (18.5-18.6)

1.1 (1.0-1.2)

9.7

Gala

21.2

1

8.8

Honeycrisp

19.5 (18.9-20.1)

1.3 (1.0-1.6)

10.7

Individual variety results

Gingergold harvest is underway and these fruit were sampled from one site in Leelanau County. Apple maturity test results indicated these fruit are firm with low starch levels and 11.8 percent brix. The cool weather has resulted in nice pink cheeks on these fruit.

Gingergold maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Aug. 30

19.7

1

11.8

Redfree is a minor variety grown in this region and some growers of this variety have already started harvesting Redfree. One block in Leelanau County was sampled this week and results indicated these apples are very firm with a low starch index and 10.7 percent brix.

Redfree maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Aug. 30

22.9

1

10.7

McIntosh apples are coloring up nicely throughout the region. However, there is still some time before these apples will be ready for harvest.

McIntosh maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Aug. 30

18.6 (18.5-18.6)

1.1 (1.0-1.2)

9.7

Gala apples are also showing nice color. Several blocks have a lot of fruit and size is a concern. Apple maturity tests indicated these apples need more time to ripen with low starch levels and brix percentages.

Gala maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Aug. 30

21.2

1

8.8

Honeycrisp apples have very nice size and color this season. Some trees are dropping fruit due to bitter pit, particularly in blocks with light crops. These fruit still have some time before they are ready to be harvested, and growers are hoping for increased brix percentages in the coming weeks.

Honeycrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch (range)

Brix %

Aug. 30

19.5 (18.9-20.1)

1.3 (1.0-1.6)

10.7

 

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.

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