Southeast Michigan apple maturity report – September 24, 2014

The pace of apple harvest slows for many growers waiting for fruit to mature.

General apple harvest comments

Every apple harvest is different and unique, but harvest this year is more different than any I have experienced. The best way to describe harvest this week is that we are in between varieties. Some varieties like Gala, Honeycrisp and Cortland were very slow to mature this year, as evidenced by lower than normal internal ethylene levels, lower starch readings and much lower brix or sugar levels. Apple harvest continues, but in the past week most growers have found that they are caught up with harvest and are waiting for other varieties to ripen more so they can begin harvest. So, growers have slowed the pace of harvest, giving their harvest crews the weekend off and shortening their work day a bit. Currently, there seems to be a gap between Gala, McIntosh and Honeycrisp and the next set of varieties to mature, like Jonathan and Golden Delicious. Jonagold is the only exception to this, with details to follow.

This week I repeated apple maturity testing on the six varieties tested last week and added two new varieties that are approaching maturity. Growers are picking the latest to mature Gala strains and Retain-treated Gala and McIntosh. Honeycrisp are being harvested for the third or fourth, and final, picking. It appears that Jonagold are maturing quicker than other varieties this season, ahead of Empire and Jonathan.

With abundant soil moisture supplies this season at most fruit farms, fruit size is generally excellent. Cooler temperatures have caused fruit color to improve again in the last week. Internal ethylene levels are low in most varieties. I am noting that the brix or sugar levels have been lower this season compared to most seasons, but have taken a nice leap in the past week. These lower brix levels are most likely related to more water being in the fruit due to abundant soil moisture supplies at most fruit farms.   

Apple maturity in southeast Michigan for apples harvested Sept. 21, 2014

Variety

% fruits with ethylene
over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %

Empire

0 (0-0)

71 (55-79)

16.3  (15.9-17.0)

2.6 (2.1-3.4)

11.2

Cortland

0 (0-0)

74 (73-75)

15.6  (14.5-16.6)

1.6 (1.5-1.7)

11.6

Jonathan

40 (40-40)

92 (84-99)

16.8  (15.5-18.0)

2.7 (1.9-3.5)

12.8

Jonagold

0 (0-0)

62 (54-67)

16.0  (14.1-17.8)

3.9 (2.3-5.6)

12.2

Golden Delicious

0 (0-0)

13 (8-19)

17.0  (16.1-17.5)

1.8 (1.6-2.1)

12.9

Red Delicious

30 (0-60)

93 (90-97)

15.8  (15.1-16.6)

1.3 (1.0-2.3)

 9.5

Idared

0 (0-0)

65 (62-68)

16.7  (14.9-18.8)

1.4 (1.2-1.5)

10.7

Northern Spy

20 (20-20)

34 (29-38)

21.8  (20.7-22.8)

1.7 (1.4-2.0)

10.3

Individual variety results

Empire was sampled for the third week of the season and appears to be another week or so from being ready to begin harvest, even for controlled atmosphere (CA) and long-term storage. I discovered an error in the data that I used in last week’s reporting on Empire maturity. I have recalculated that data and am using the updated figures in make the following comments and observations. None of the blocks tested this week had internal ethylene levels greater than 0.2 parts per million (ppm). Fruit color is good, averaging 71 percent, about the same as last week. Pressure is averaging 16.3 pounds, dropping from 17.0 pounds last week. The starch removal averaged 2.6, up a half point from 2.0 last week. The brix is up from 10.5 percent last week to 11.2 percent this week. In summary, Empire is not ready for harvest at this time and is slow to mature this year.

Cortland was sampled for the third week of the season and is still a long way from being ready to begin harvest. None of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is good, averaging 74 percent, and pressure is averaging 15.6 pounds. The starch removal averaged only 1.6 this week, up from 1.0 last week. The brix is 11.6 percent this week, up from 10.5 percent last week. This variety is maturing very slowly this season as well.

Jonathan was sampled for the second week of the season and also appears to be a long way off at this time. There is a start to internal ethylene development in Jonathan this week, with 40 percent of blocks tested, producing internal ethylene levels greater than 0.2 ppm. Fruit color is excellent, averaging 92 percent, and pressure is excellent, averaging 16.8 pounds. The starch removal averaged 2.7 this week, up from 2.3 last week. The brix levels are up from 11.6 percent last week to 12.8 percent this week. Here again, Jonathan’s are not ready for harvest at this time and are slow to mature this year.

Jonagold was sampled for the second week of the season; I added more blocks to my sample this week. Some blocks or strains are ready to harvest now, while others need to have a few more days to mature. Jonagold is ahead of Empire, Cortland and Jonathan this season. While internal ethylene levels greater than 0.2 ppm remain low, fruit color is good (for Jonagold), averaging 62 percent and pressure is averaging 16.0 pounds. The starch removal averaged 3.9, with a brix of 12.2 percent.

Golden Delicious was sampled for the second week of the season and appears to be a long way off at this time. None of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is poor to fair, averaging 13 percent, and pressure is averaging 17.0 pounds. The starch removal averaged 1.8, up from 1.3 last week, with a brix at 12.9 percent.

Red Delicious (Redchief strain) was sampled for the first week of the season and is a very long way off at this time. Almost one-third, or 30 percent, of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is average at 93 percent and pressure is averaging at 15.8 pounds. The starch removal averaged 1.3, with a brix very low at 9.5 percent. Again, Red Delicious is a long way from being ready to begin harvest.

Ida Red was sampled for the first week of the season and appears to be a very long way off at this time. None of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is average at 65 percent and pressure is averaging 16.7 pounds. The starch removal averaged 1.4, with a brix very low at 10.7 percent.

Northern Spy was sampled for the second week of the season and appears to be a long way off at this time. Internal ethylene levels in fruit greater than 0.2 ppm rose to 20 percent this week. Fruit color is average at 34 percent and pressure is averaging 21.8 pounds. The starch removal averaged 1.7, with a brix low at 10.3 percent.

Predicted apple harvest dates

Each year we publish a predicted harvest date for three varieties for many locations across the state. This year’s dates can be seen at “Predicted 2014 apple harvest dates,” published July 17. The table below lists the bloom and harvest dates for the Michigan cities Deerfield and Romeo. You can adjust your predicted harvest dates based on your bloom dates. The harvest dates are based on a long established formula using the bloom date and temperatures for 30 days post-bloom. These dates are an estimate, and from the data I generated from this week’s samples, I believe that these harvest days are going to be fairly close to the actual dates for a variety nearing maturity.

Predicted harvest dates for southeast Michigan

Full bloom date

 Predicted harvest dates

Station

McIntosh

Jons

Reds

McIntosh

Jons

Reds

Deerfield

5/12

5/14

5/16

9/12

9/30

10/7

Romeo

5/15

5/17

5/17

9/14

10/1

10/7

Looking for more? View Michigan State University Extension’s Apple Maturity Program and Reports resource page for regional reports throughout the state and additional resources.

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