West central Michigan apple maturity report – October 14, 2015

Amy Irish-Brown<irisha@msu.edu>, and Phil Schwallier, Michigan State University Extension - October 15, 2015

Apple harvest in west central Michigan is nearing an end.

General comments

The weather continues to be wonderful for color and sugar development in apples and for getting them harvested. There is some very cold weather in the forecast for the coming weekend. Lows right around freezing probably won’t cause any damage to fruit, but it will loosen up apples. Reminder: hanging fruit do freeze, do not handle them until they have thawed completely. You could see an increase in bruising if picking wet fruit after colder overnight temperatures.

Late last week I had the first ever brown marmorated stink bug identified on the Ridge proper. We have been catching them in traps and on houses in the Grand Rapids, Michigan, area, but not yet in an orchard near Sparta, Michigan. The numbers across the southern areas of Michigan are up this year and while this is no reason to panic, it does remind us that we need to be on the lookout for them or their feeding damage. With bitter pit being so much higher this year, it might be easy to confuse brown marmorated stink bug damage and bitter pit. Contact me at irisha@msu.edu if you find suspicious stink bugs or their injury and we can identify them.

For the Hart/Shelby, Michigan, area, growers can expect harvest dates for that area to be behind the Grand Rapids area using this guide: along the lakeshore approximately six days behind Grand Rapids; areas inland about four days behind.

Normal and 2015 peak harvest dates for varieties for the Grand Rapids area
Variety	Normal date	2015 predicted date
Red Delicious	10/5/15	10/5/15
Idared	10/10/15	10/10/15
Rome	10/15/15	10/15/15
Fuji	10/25/15	10/25/15
Braeburn	10/25/15	10/25/15
Goldrush	11/1/15	11/1/15

Individual variety results

Red Delicious were sampled for the fourth week. All maturity tests continue to indicate a very slow movement forward for Reds. They are still in the window for mid- to long-term CA storage, but that could change quickly with the increase in internal ethylene and the cooler weather that is predicted.

Red Delicious 2015 maturity sampling records
Date of sample	Avg. ethylene (ppm)	% Fruits with ethylene over 0.2 ppm	Red color % (range)	Background color (range) 1=yellow 5=green	Firmness lbs. pressure (range)	Starch (range)	Brix (range)
Sept. 22	0.368	20	68 (45-95)	2.8 (2-3)	18.4 (15-20.5)	1.5 (1-4)	10.3(10-11)
Sept. 29	4.291	45	91.9 (75-100)	1.6 (1-3)	18.1 (15.5-21.5)	2.9 (1-7)	11.2 (10-15)
Oct. 6	1.508	10	78 (50-100)	2 (1-4)	17.6 (14.8-20.5)	2.7 (2-4)	10.3 (10-11)
Oct. 13	11.8	90%	80 (65-90)	1.5 (1-2)	17.1 (14.5-18)	2.8 (2-6)	11.4 (10.5-13)

Ida Red predicted harvest date was Oct. 10 and many have been harvested in the last week. This variety moved quickly from conditions for long-term CA storage to only short-term storage if they are still hanging. Don’t wait on Ida Red if you still have them on the tree.

Ida Red 2015 maturity sampling records
Date of sample	Avg. ethylene (ppm)	% Fruits with ethylene over 0.2 ppm	Red color % (range)	Background color (range) 1=yellow 5=green	Firmness lbs. pressure (range)	Starch (range)	Brix (range)
Sept. 22	0.432	80	75 (50-95)	3.2 (2-5)	20.9 (18-23.5)	1.8 (1-2)	10.9(10-12)
Sept. 29	0.7727	70	81 (65-90)	2.3 (2-3)	15.5 (14-20)	3.8 (3-4)	11.6 (11-12)
Oct. 6	1.337	100	89 (75-100)	1.7 (1-3)	15 (13-16.5)	2.6 (1-4)	11.2 (10-12.5)
Oct. 13	14.227	100	71 (60-80)	3.1 (2-4)	14.5 (11.5-16.5)	3.7 (2-6)	11.3 (10.5-13)

Fuji predicted harvest date is Oct. 25. This date appears to be five to seven days late. In the last day or two, I see growers on the Ridge have started harvesting Fuji. Starch staining for Fuji can be deceptive. Fuji tends to stain gray and not black like other varieties. We have noticed an increase in watercore from week to week and it will most likely get more pronounced over the next 10 days. Fuji are now approaching harvest maturity for long-term CA.

Fuji 2015 maturity sampling records
Date of sample	Avg. ethylene (ppm)	% Fruits with ethylene over 0.2 ppm	Red color % (range)	Background color (range) 1=yellow 5=green	Firmness lbs. pressure (range)	Starch (range)	Brix (range)
Sept. 29	0.444	90	52 (40-80)	2.2 (1-3)	19.6 (16.5-23)	4	13.2 (13 -14)
Oct. 6	0.269	30	82 (70-95)	1.8 (1-2)	19 (16-25)	2.2 (1-4)	12.8 (12.5-13)
Oct. 13	2.3078	100	70.5 (50-85)	2.8 (2-4)	18.3 (16-21.5)	4.6 (4-6)	13.4 (13-15)

Granny Smith was tested for the second week. All measurements indicate immaturity. The usual harvest date for Granny Smith in west Michigan is around Halloween, Oct. 31.

Granny Smith 2015 maturity sampling records

Date of sample

Avg. ethylene (ppm)

% Fruits with ethylene over 0.2 ppm

Red color % (range)

Background color (range)

1=yellow

5=green

Firmness lbs. pressure (range)

Starch (range)

Brix (range)

Oct. 6

0.0299

5 (0-15)

21.2 (19-25.5)

3.3 (3-4)

11.6 (11-12)

Oct. 13

0.1186

7.5 (5-15)

20.5 (17-25)

3.8 (3-4)

11.7 (11-12)

Braeburn was tested for the second week. Fruit measurements made movement forward in maturity, but overall Braeburn is still immature. Another week of testing will really show us if our Oct. 25 predicted harvest date for long-term CA storage is accurate.

Braeburn 2015 maturity sampling records

Date of sample

Avg. ethylene (ppm)

% Fruits with ethylene over 0.2 ppm

Red color % (range)

Background color (range)

1=yellow

5=green

Firmness lbs. pressure (range)

Starch (range)

Brix (range)

Oct. 6

0.0966

33 (20-55)

3.6 (3-4)

20.6 (18.5-22)

2 (1-3)

9.2 (9-9.5)

Oct. 13

0.2965

59 (45-70)

22.6 (20-24.5)

1.8 (1-2)

10.1 (9.5-11)

Cameo was tested for the first week. I am still not sure where to put Cameo on the harvest schedule – I hear many different dates from different growers. There are not many Cameo planted in Michigan and growers tell me they target harvest for about a week after Rome or maybe in the Fuji window or a little later, but they hang and stay hard for a long time so you can get to them when time permits. At this time, our tests indicate immature fruits for Cameo for this first week of sampling, but we probably should have tested them a week ago.

Cameo 2015 maturity sampling records

Date of sample

Avg. ethylene (ppm)

% Fruits with ethylene over 0.2 ppm

Red color % (range)

Background color (range)

1=yellow

5=green

Firmness lbs. pressure (range)

Starch (range)

Brix (range)

Oct. 13

0.2542

25%

55 (15-80)

2.7 (1-4)

19.2 (15-24)

3 (2-5)

12.6 (11.5-13.5)

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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