Southeast Michigan apple maturity report – October 16, 2013

With the good run of weather, apple growers have made great progress on harvest operations and are now seeing that the finish line is near.

General apple harvest comments

Apple harvest is quickly moving to completion toward the end of this week to early next week for many growers, especially where harvest labor has been adequate. Growers are harvesting many varieties at this time, including finishing Golden Delicious, Northern Spy and Cameo, and are continuing to work away at the later strains of Red Delicious and starting on Fuji. Some growers are just starting Ida Reds. Growers are waiting for Braeburn and Rome to mature a bit more before harvesting them. Most apple growers report they are harvesting a nice crop this season; however, most have gone on to say they have not had a record apple crop as other parts of the state are experiencing. I feel this is mainly due to the Mother’s Day (May 12, 2013) frost event across most of the region.

Remember that varieties are maturing in a different order this season. As I shared last week, growers need to consider leaving some varieties to hang for a bit longer and move onto 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. Harvest labor shortages continue for most fruit farms; however, on our best managed farms with good housing, labor supplies have been fine.

This is the final Southeast Michigan Apple Harvest Report for the 2013 growing season. Michigan State University Extension staff involved in the apple maturity project will be emailing a short survey to growers in a few weeks to gain insights on the effectiveness of this work and suggestions on improvements for the future. The survey will also be available through the MSU Extension Fruit & Nuts page.

Apple maturity in southeast Michigan for apples harvested on Oct. 14, 2013


% Fruits with Ethylene
over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix (%)

Red Delicious

75 (50-100)

98 (96-100)

15.1 (14.7-15.5)

3.3 (3.0-3.6)


Ida Red

95 (90-100)

88 (85-91)

13.8 (13.7-13.8)

3.3 (2.2-4.3)


Northern Spy

100 (100-100)

75 (57-92)

17.5 (16.6-18.3)

6.3 (5.5-7.1)



100 (100-100)

85 (81-88)

17.2 (16.8-17.6)

5.2 (4.5-5.8)




40 (30-50)

15.4 (13.0-17.6)

3.6 (2.0-5.0)


Individual variety results

Red Delicious was sampled for the fourth week of the season, Redchief and Ace were the strains tested this week and this was the first time to sample Ace. So, the data in the table above are the results of both strains. All Red Delicious strains have been slow to mature this season. Most strains have been harvested. Redchief have been harvested or are now ready for harvest and Ace are getting close to being ready. All Red Delicious picked very easy this week, so be sure to watch for them to loosen to the point of fruit drop. Some of the early maturing strains had a significant amount of water core in them.

Lastly, of all the many times I have tasted Red Delicious this season, I have yet to sample one that eats well. They continue to test with much higher levels of internal ethylene greater than 0.2 parts per million (ppm), at 75 percent this week. Color is excellent and unchanged at 98 percent; pressure is about the same as last week at 15.1 pounds. The starch has moved in this blended sample to 3.3 this week and brix tested at 10.2 percent this week. Again, some strains are over-mature for long-term and CA storage; others are just coming into the mature window.

Ida Red was sampled for the fourth week of the season and, as I shared last week, are testing about the same as Red Delicious this season. They are showing that 95 percent of tested fruit are above the 0.2 ppm level of internal ethylene, up from 90 percent last week. Color is good and unchanged at 88 percent this week; pressure has dropped to 13.8 pounds, down from 14.9 pounds last week. The starch has moved from 2.0 last week to 3.3 this week and brix is down a full percentage point to 11.7 percent this week. Ida Red are now ready for both long-term and CA storage harvest and nearly ready for fresh and immediate sales.

Northern Spy was sampled for the fourth week of the season and maturity has jumped well ahead of Red Delicious and Ida Red. Most have been harvested. They are past their prime for harvest for long-term and CA storage and some even 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 75 percent, pressure has dropped from18.4 pounds last week to 17.5 pounds this week, the starch removal index is up from 4.1 last week to 6.3 this week, and brix is up to 12.5 percent.

Fuji was sampled for the third week of the season. The results of maturity testing indicate they have quickly moved from being ready for harvest last week for long-term and CA storage to being ready for immediate fresh market sales this week. The internal ethylene levels of fruit greater than 0.2 ppm tested at 100 percent, with color up to 85 percent, pressure remains firm at 17.2 pounds this week, the starch has moved from 4.4 last week to 5.2 this week and brix rose one percentage point to 14.6 percent this week.

Candycrisp was sampled for the second week of the season. This variety normally matures four to five days behind Red Delicious, is mature for long-term and CA storage harvest and about four to five days from being ready for fresh and immediate sales. The internal ethylene levels of fruit greater than 0.2 ppm is 70 percent with color or blush at 40 percent, pressure testing at 15.4 pounds, the starch index moved from 2.4 last week to 3.6 this week and brix at 13.2 percent.

Predicted harvest dates for East 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 .(JavaScript must be enabled to view this email address), Office phone 810-244-8555, cell 810-516-3800 and fax 810-341-1729.

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