Northwest Michigan apple maturity report – Oct. 9, 2019

Growers took advantage of this week’s sunny and dry weather, which was ideal for picking crews.

General apple harvest comments

The weather has cooperated beautifully for apple harvest over this past week and as a result, growers are moving along with their 2019 harvest. Many of the orchards we sample in and around Suttons Bay, Michigan, are already harvested, so we found few of the more common varieties in this neck of the woods. Many growers are targeting Honeycrisp, and many of the orchards have already been harvested while some growers are still on their first picking.

There seems to be more variability in harvest timing this season. Some growers are waiting on color and some apples are still not a ripe as growers would like to be for harvest. Growers are trying to get as much harvested this week as the weather forecast is predicting rain/storms for the weekend followed by more rain into next week.

Apples are eating well this season and fruit is particularly juicy. Many growers commented on how nice the fruit looks; size is good across varieties and growers that had good pruning programs have great color. The recent cool, overnight temperatures will continue to improve color on fruit. Firmness also seems to be holding in all varieties. Overall, quality is excellent.

Bitter pit is somewhat variable across orchards. We have heard from growers that some people have used less calcium this season, mostly as a cost saving technique, but orchards that did not have as much calcium look pretty good with minimal bitter pit. We observed differences in bitter pit in our NC-140 rootstock trial where some rootstocks had significantly more bitter pit than others. We intend to report on these findings at the Northwest Orchard and Vineyard Show this coming January.

We still have not caught brown marmorated stink bugs in our traps, but we have observed some in more urban areas of the region. In particular, we have observed flushes of brown marmorated stink bug activity during the evening hours around 6 p.m. We have also found San Jose scale on some of our fruit that we harvested at the Northwest Michigan Horticulture Research Center this week.

Apple maturity in northwest Michigan for apples collected on Oct. 8, 2019

Variety

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Jonagold

69.5

18.6

6

14.3

Idared

78.5

18.9

2.6

13.1

Golden Delicious

13 (13.0 - 13.0)

17.7 (17.2-18.2)

6.0 (5.8 - 6.0)

12.1 (11.5 -12.7)

Individual variety results

Jonagold

This is the second week of testing Jonagold, and we sampled one block. Overall, apples have been firm this season including this week’s Jonagold sample. These apples continue to have high starch readings, but color improvements would be welcomed.

Jonagold maturity sampling for the harvest season

Sample date

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 1

74.8 (70 - 79.5)

18.4 (18.1 - 18.7)

4.4 (4.4)

14.7 (13.9 - 15.4)

Oct. 8

69.5

18.6

6

14.3

Idared

This is the second week of testing for Idared, and we sampled one block. Firmness is decreasing, color is continuing to improve as well as brix. Starch readings suggest these apples are still not quite ready for fresh eating.

Idared maturity sampling for the harvest season

Sample date

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 1

71

19.6

1.5

12.8

Oct. 8

78.5

18.9

2.6

13.1

Golden Delicious

This is the first week of testing for Golden Delicious and we tested two samples. Starch indices are testing higher than anticipated for this variety at this time of year and the apples are still eating green.

Golden Delicious maturity sampling for the harvest season

Sample date

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Oct. 8

13 (13.0 - 13.0)

17.7 (17.2-18.2)

6.0 (5.8 - 6.0)

12.1 (11.5 -12.7)

 

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.)

 

Did you find this article useful?


You Might Also Be Interested In