Northwest Michigan apple maturity report – Oct. 10, 2018

Wet conditions have slowed harvest and many of the blocks we select for maturity have been harvested.

General apple harvest comments

This is the seventh 2018 apple maturity report from northwest Michigan, and apples are harder to find to sample this week. Although we have had more difficulty finding fruit to sample, many growers are still picking Honeycrisp. Most growers are on their second or third pick of this variety, but we spoke to a grower today that was still on the first picking. There are some growers that are short on labor and the shortage of pickers has slowed harvest.

Honeycrisp fruit is still looking good overall, but bitter pit has been a challenge in some blocks that have yet to finish harvest. We have also observed more bitter pit showing up in stored fruit that we harvested at the Northwest Michigan Horticulture Research Center in the last three weeks. Gala harvest is underway and many McIntosh blocks have been picked for the processing market. McIntosh are eating better this week and color on older strains has improved. Growers are picking all varieties that are close to mature based on requests from processors. Fruit quality is still holding and color continues to improve the longer the fruit hangs on the tree. 

The wet weather continues to pose harvest challenges. In fact, the Northwest Michigan Horticulture Research Center Enviroweather station has recorded rain every day since last Monday, Oct. 1. The following rainfall events were recorded for Oct. 1-8: 0.82 inch, 0.12 inch, 0.63 inch, 0.41 inch, 0.03 inch, 0.04 inch, 0.1 inch and 0.7 inch. No rain was recorded yesterday, Oct. 9, but rain is in the forecast again today.

We have had over 3 inches of rain in the month of October thus far. We had some warm weather last Wednesday and Thursday, Oct. 3 and 4, with daytime temperatures in the high 70s to low 80s. Conditions were cool over the weekend and daytime temperatures were back up in the mid- to high 70s on Monday and Tuesday. Conditions are expected to cool for the weekend.

Apple maturity in northwest Michigan for apple collected on Oct. 9

Variety

Firmness lbs. (range)

Starch (range)

Brix

Color %

Ida Red

16.95 (16.7-17.2)

3.3 (2.5-4.0)

12.8

97

JonaPrince

19.8

5.9

14.8

100

Empire

17.8

4.3

12.7

86

Individual apple variety results

This is our first week of sampling Ida Red and the two blocks we sampled showed some variability in maturity, particularly in starch levels. Overall, these apples are firm with good color. Some blocks that will go into storage are almost ready for harvest and other blocks with lower starch levels are ready to be eaten fresh.

Ida Red maturing sampling for the harvest season

Variety

Firmness lbs. (range)

Starch (range)

Brix

Color %

Ida Red

16.95 (16.7-17.2)

3.3 (2.5-4.0)

12.8

97

We tested one sample of JonaPrince Jonagold and these apples are firm with increasing brix and excellent color. Starch levels indicate these apples are ready for fresh eating.

JonaPrince maturity sampling for the harvest season

Date

Firmness lbs. (range)

Starch (range)

Brix

Color %

Oct. 2

19.4

3.1

14.1

100

Oct. 9

19.8

5.9

14.8

100

We tested one sample of Empire this week and maturity results indicated this block is ready for harvest. Like the other varieties we tested, these apples are also firm. Color is also decent, but color has been a challenge this season.

Empire maturity sampling for the harvest season

Date

Firmness lbs. (range)

Starch (range)

Brix

Color %

Oct. 9

17.8

4.3

12.7

86

 

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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