West central Michigan apple maturity report – Sept. 6, 2017

Historically, we assumed harvest in the west central region lags behind the Ridge, however this does not seem to be the case this season in many areas.

General harvest comments

Harvest of early Gala blocks is getting underway in the region. McIntosh is generally lagging just behind Gala this season, but will probably be the next cultivar to come out of most orchards. Growers are starting to eye early picks in some Honeycrisp blocks., but the start of harvest is still at least a week away at most sites. Deciding to pick based on appearance of fruit is tricky this year because color is so good. Many blocks are full of bright red fruit that still has at least a week to go before full maturity. Rainy conditions near harvest mean that some growers will be opting for a pre-harvest spray to protect fruit quality in post-harvest storage conditions. Michigan State University Extension reports Pristine is typically the product of choice in this situation.

Counts of brown marmorated stink bugs (BMSB) are still very low in the area, though they have been detected in small numbers elsewhere in the state. Our BMSB traps in west central did not catch any adults or nymphs in the past seven days. Apple maggot catches continue, but are low. Second generation of codling moth is over, and trap counts have dropped down to zeros in most blocks. While certain hot spots may still see some adults, numbers are down and damage is generally very low this season. We are not expecting a third generation. We are at peak egg hatch for the last generation of oriental fruit moth for the season. If you trap 50 or more oriental fruit moths in an apple block in a week, a cover spray is warranted to protect fruit from damage.

The normal and estimated 2017 peak harvest dates for apple varieties in Grand Rapids, Michigan is included at the end of this report. While we have historically assumed that we lag behind the Ridge in the west central region, this does not seem to be the case this season in many areas. Gala and McIntosh are either right with or only just behind Ridge harvest maturity measurements. Generally, growers in the Elbridge, Hart and Shelby areas are tracking consistently with Ridge harvest predictions, while growers near the lake in the Clay Banks and Ludington area are generally about 3 to 5 days behind.

Data in the following tables are based on samples collected from commercial orchards in Oceana and Mason counties. Firmness and starch ranges are the observed low and high mean values.

Apple maturity for west central Michigan apples harvested Sept. 4

Variety

Firmness lbs. (range)

Starch index (range)

Brix % (range)

Honeycrisp

16.15 (11.5-19.5)

2.71 (1-6)

11.7 (10-15)

McIntosh

14.9 (12.5-18.5)

3.7 (1-5)

12.55 (11.5-14.5)

Gala

19.612 (16-24.5)

2.49 (1-6)

11.74 (10-13.5)

Individual variety results

Early Fuji was tested for the second time this week. The long-term storage starch index recommendation for this cultivars is 3 and fruits this week tested just over that mark. Harvest of this cultivar will start this week. Color and size are generally good.

Early Fuji maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch index (range)

Brix %

Aug. 25

18.12 (15.5-25)

2.2 (1-4)

12 (10.5-14.5)

Sept. 4

15.25 (11-18.5)

3.2 (1-6)

12.25 (11-14)

Honeycrisp was sampled for the third time this week. Target starch index for this variety is 3.5, and the predicted harvest for the Grand Rapids area is Sept. 15. Starch index averages for the west central region are still well under the 3.5 mark, indicating that harvest at most sites is still at least a week away. However, some early sites had a few fruit with indices as high as 6, so some growers will pick a few early Honeycrisp this week. The Sept. 15 harvest date prediction for Grand Rapids is proving to be a little bit later than what we are actually seeing in the field this season both here and on the Ridge.

Honeycrisp maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch index (range)

Brix % (range)

Aug. 25

18.86 (14-22)

1.33 (1-3)

11 (19.5 - 13.5)

Sept. 4

16.15 (11.5-19.5)

2.71 (1-6)

11.7 (10-15)

Gala was sampled for the third time this week. Most sites are still a little bit behind the target of a 3.0 starch index rating for long-term CA storage, but some earlier blocks with good size and color tested above that mark and will be harvested this week. Color on Gala is excellent this year, but size is variable. Growers are keeping an eye on stem end cracking with the rains coming close to harvest. This cultivar is often prone to this problem when heavy rain falls near harvest.

Gala maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch index (range)

Brix % (range)

Aug. 25

22.14 (18-24)

1.3 (1-4)

11.5 (10.5-14.5)

Sept. 4

19.612 (16-24.5)

2.49 (1-6)

11.74 (10-13.5)

McIntosh was also sampled for the third time late this week. Like Gala, the predicted harvest date for McIntosh in Grand Rapids is Sept. 5. McIntosh is generally lagging a little bit behind Gala this year, most sites still have a few days to go before they hit the starch index target of 5 for long-term CA storage.

McIntosh maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch index (range)

Brix % (range)

Sept. 4

14.9 (12.5-18.5)

3.7 (1-5)

12.55 (11.5-14.5)

Jonagold was sampled for the first time this week. The target starch index rating for long-term CA storage is 3.5, so most sites have at least a couple more weeks to go. Color on Jonagold is outstanding this year, but excessive size is an issue in some blocks that are bearing a light crop due to loss from the spring frosts.

Jonagold maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch index (range)

Brix % (range)

Sept. 4

18.51 (16.5-20)

2.83 (1-4)

11.81 (9.5-14)

Jonathan was also tested for the first time this week. The starch index target for long-term CA storage is 3.5, and fruit this week all tested at a 3.0. While the starch conversion still has a way to go, color on Jonathan is excellent, and fruit size is also good.

Jonathan maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch index (range)

Brix % (range)

Sept. 4

17.55 (15.5-20)

3 (3)

11.34 (10.5-12.5)

Empire was sampled for the first time this week. Size and color are generally poor on this cultivar. Fruit still have at least a couple of weeks to go before they will get to the target starch index rating of 3.5.

Empire maturity sampling for the harvest season

Sample date

Firmness lbs. (range)

Starch index (range)

Brix % (range)

Sept. 4

18.25

2.2

10.39

 

Predicted harvest dates for Grand Rapids, MI

Variety

Normal date

2017 Predicted Date

Paulared

Aug. 24

Aug. 19

Gingergold

Aug. 26

Aug. 21

Gala

Sept. 10

Sept. 5

McIntosh

Sept. 15

Sept. 5

Honeycrisp

Sept. 18

Sept. 15

Empire

Sept. 26

Sept. 25

Jonathan

Sept. 28

Sept. 27

Jonagold

Sept. 28

Sept. 27

Golden Delicious

Oct. 2

Oct. 1

Red Delicious

Oct. 5

Oct. 4

Idared

Oct. 10

Oct. 9

Rome

Oct. 15

Oct. 14

Fuji

Oct. 25

Oct. 24

Braeburn

Oct. 25

Oct. 24

Goldrush

Nov. 1

Oct. 31

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