Southeast Michigan apple maturity report – September 11, 2013

Apple harvest is in full swing this week with Gala being harvested and Honeycrisp and McIntosh being spot-picked.

General apple harvest comments

Apple growers are harvesting most Gala strains and are spot-picking Honeycrisp and McIntosh. Fruit from these varieties have taken on a nice swell in the last week; size has improved dramatically in areas that have received adequate rainfall over the last month or so. In areas where rainfall has been short over this same time, Gala size has continued to be a challenge. Gala have been slower to mature in the last week when compared to Honeycrisp and McIntosh. This is reflective of our experiences over the years that Gala prefers a hot and high degree day growing season compared to one like this season that has been cooler.

The starch level in Honeycrisp blocks tested this week has jumped three full numbers in the past week, from 2.0 last week to 5.0 this week. In some Honeycrisp blocks with good fruit size, I am finding between 10-20 percent of the largest fruit affected with bitter pit. McIntosh color is a challenge for most growers and with the warm temperatures of the last few days will continue to retard red blush development in many varieties. Early Fiji and Empire were also tested this week and both need more time to mature. The overall average brix levels have increased a full percentage point in the last week. Some blocks have some sun scald issues from the heat of the last month. Many apples I harvested for my samples this week picked easy, however with very little fruit drop. Harvest labor is running short for most apple growers as we have ramped up harvest operations in the last week.    

Apple maturity in southeast Michigan for apples harvested on Sept. 9, 2013.


% Fruits with ethylene over 0.2 ppm (range)

Color % (range)

Firmness lbs. (range)

Starch (range)

Brix %



90% (88-91%)

19.6 lbs. (16.8-22.4)

3.8 (2.0-5.5)



30% (20-40%)

61% (35-87%)

15.1 lbs. (14.7-15.4)

3.7 (3.6-3.8)




80% (78-82%)

14.8 lbs. (14.1-15.5)

5.0 (4.0-5.9)


Early Fuji


66% (50-90%)

17.1 lbs. (14.6-20.2)

2.4 (1.0-3.0)




48% (46-51%)

18.0 lbs. (17.8-18.1)

2.1 (2.1-2.1)


Individual variety results

Gala were sampled for the second week of the fall harvest season. Growers are harvesting early and mid-season Gala strains. Fruit took on a nice swell in the last week where growers have received adequate rainfall in the last month. Fruit size continues to be a problem where soils have been dry. All of the fruit sampled this week are showing internal ethylene levels greater than 0.2 parts per million (ppm). The fruit pressure has dropped 2 pounds in the last week, now averaging 19.6 pounds. The starch index has jumped from 2.2 last week to 3.8 this week with a brix of 12.2 percent.

McIntosh was sampled for the second week of the season and are eating much better than last week. Most apple growers are spot-picking McIntosh for color and size for immediate sales this week and weekend and will move into heavier harvest early next week. Growers are waiting for better color and size before they get too heavily into harvest. The color has improved in McIntosh from 51 percent last week to 61 percent this week, which is better but not what growers are hoping for. Fruit firmness remains good to excellent at 15.1 pounds with a 1.5-pound drop in the last week. The starch removal is fine at 3.7; recall that McIntosh need to be closer to 5 to be considered mature, higher than any other variety, in the range of 10 to 20 percent.

Honeycrisp were sampled for the second week of the season. As with all samples taken for the apple maturity program, I collect the most mature fruit from the outside of the tree. This is key to keep in perspective for my Honeycrisp data and comments that follow. Honeycrisp always have a wide range of fruit maturity and this season it is more pronounced than ever, with fruit on the outside of the tree now being mature and ready for harvest and fruit on the inside of the tree remaining green as grass. All fruit tested this week had internal ethylene levels greater than 0.2 ppm. The color of fruit sampled from the outside of the tree has jumped from 67 percent last week to 80 percent this week and fruit firmness has dropped over 0.5 pounds to 14.8 pounds this week. The starch removal has leapt from an average of 2.0 last week to an average of 5.0 this week. In all of my years of experience with Honeycrisp maturity, I have never seen this much of a jump in the starch level in one week. The brix level is 12.8 percent, up from 11.6 percent last week. There is more bitter pit showing up in Honeycrisp than any other variety so far this season.

Early Fuji were sampled for the second time of the season with 40 percent of the fruit showing internal ethylene levels greater than 0.2 ppm. The color remains fair at 60 percent and the fruit are firm at 17.1 pounds. Fruit starch removal index is 2.4, up from 2.0 last week. The brix is 11.4 percent. Early Fuji are not ready for harvest at this time; I think they will be ready for harvest in a week.

Empire were sampled for the first time this season. Internal ethylene levels remain low, color poor at 49 percent and fruit are firm at 18.0 pounds. I was surprised to see the starch at 2.1 and a brix of 10.9 percent. It is too early to begin Empire harvest; I will get a better read on its maturity in next week’s testing.

Predicted harvest dates for southeast Michigan.

Full bloom date

Predicted harvest dates






















The Southeast Michigan Apple Harvest Report is produced by Bob Tritten, district fruit educator, Flint, Mich. Email, office phone 810-244-8555, cell 810-516-3800 and fax 810-341-1729.

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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