Southeast Michigan apple maturity report – October 9, 2013

Apple harvest is well over half-way toward completion in southeast Michigan.

General apple harvest comments

Apple harvest is all over the board this week, with some growers moving onto other varieties that are maturing in a different order this season. Most growers have nearly finished harvest of Jonagold and Golden Delicious, about half-way complete with Empire, and are starting on Northern Spy and a few strains of Red Delicious, and in the last day or so, early strains and sites of Fuji. Red Delicious and Ida Reds are slow to mature this season.

With the exception of Sunday, Oct. 6, 2013, the weather has been favorable for harvest. Harvest labor shortages continue for most fruit farms, however on our best managed farms with good housing, labor supplies have been fine and some farms gave harvest crews the weekend off to allow fruit to ripen a bit before continuing harvest operations. As I shared last week, growers need to consider leaving some varieties to hang for a bit longer and move on to other varieties that are at their peak of maturity and are more valuable being harvested in prime condition. Growers can then go back to these partially harvested varieties later on that are intended for processing or juice.

Apple maturity in southeast Michigan for apples harvested on Oct. 7, 2013


% Fruits with Ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix (%)

Red Delicious

85 (80-90)

99 (97-100)

14.8 (14.5-15.1)

3.0 (2.7-3.3)


Ida Red

90 (80-100)

90 (85-95)

14.9 (14.0-15.8)

2.0 (1.4-2.6)


Northern Spy

100 (100-100)

70 (65-75)

18.4 (18.1-18.6)

4.1 (3.1-5.0)



 70 (50-90)

80 (79-81)

16.4 (16.3-16.4)

4.4 (4.0-4.7)




23 (10-35)

14.9 (12.0-17.5)

2.4 (1.0-3.0)


Individual variety results

Red Delicious was sampled for the third week of the season, Redchief was the strain tested. Red Delicious is maturing slowly; their maturity is quite a ways behind Goldens this season. Growers have picked or are just beginning to harvest early maturing strains of Red Delicious. Some of the early maturing strains have a significant amount of water core in them. They are also picking easy this week.

Red Delicious are showing much higher levels of fruits with internal ethylene greater than 0.2 parts per million (ppm), up from 15 percent last week to 85 percent this week. Color is excellent and unchanged at 99 percent; pressure has dropped over 2 pounds from 17.1 pounds last week to 14.8 pounds this week –  it is unusual to see this much drop in one week. The starch is unchanged at 3.0 and brix rising sharply from 9.4 percent last week to 11.1 percent this week. Some strains are over-mature for long-term and CA storage while others are just coming into the mature window. The sharp drop in pressure concerns me. For fresh or immediate sales, most Red Delicious strains are still eating just a touch on the green side. The predicted harvest date for Red Delicious was Oct. 4 for Deerfield, Mich., and Oct. 8 for Romeo, Mich. I feel that they are maturing later than these dates this season.

Ida Red was sampled for the third week of the season and in maturity terms are testing about the same as Red Delicious this season. There is not the spread of maturity in Ida Red as there is in Red Delicious this season. They are showing that 90 percent of tested fruit are above the 0.2 ppm level of internal ethylene, up from 60 percent last week. Color is improving from 79 percent last week to 90 percent this week; pressure has not dropped as much as Red Delicious in the last week, but has dropped from 16.7 pounds last week to 14.9 pounds this week. The starch is about the same as last week at 2.0 and brix is up a full percentage point to 12.6 percent this week. Ida Red are still eating green at this time.

Northern Spy was sampled for the third week of the season and maturity has jumped ahead of Red Delicious and Ida Red this week. They are ready to harvest for long-term and CA storage and can be spot-picked for fresh immediate sales. They are testing at 100 percent of fruit to be above the 0.2 ppm level of internal ethylene, which is typical for Northern Spy. Color has improved to 70 percent, pressure remains firm at 18.4 pounds, starch removal index is up from 3.0 last week to 4.1 this week, and brix is unchanged at 12 percent.

Fuji was sampled for the second week of the season. The results of maturity testing indicate that they have quickly moved to a point where they are now ready for long-term and CA storage harvest and some early maturing strains and sites are ready to harvest for fresh market sales. The internal ethylene levels of fruit greater than 0.2 ppm tested at 70 percent with color at 80 percent, background color at 2.2, pressure dropped almost three pounds from 19.3 pounds last week to 16.4 pounds. this week, starch has jumped from 2.6 last week to 4.4 this week and brix rose to 13.6 percent.

Candycrisp is a new variety for growers and was sampled for the first time this season. This variety normally matures four to five days behind Red Delicious, so it is close to being mature. The internal ethylene levels of fruit greater than 0.2 ppm with color or blush at 23 percent, background color at 2.9, pressure testing at 14.9 pounds, starch was a surprising 2.4 and brix also surprisingly at 13.8 percent. Let’s see what next week’s test results on Candycrisp reveal in terms of maturity.

Predicted harvest dates for southeast Michigan

Full bloom date

 Predicted harvest dates






















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.

The East Michigan Apple Harvest Report is produced by Bob Tritten, District Fruit Educator, Flint, MI, email, Office phone 810-244-8555, cell 810-516-3800 and fax 810-341-1729.

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