MSU Extension

General apple harvest comments

A week of hot weather has quickly accelerated apple ripening, especially in Gala, Honeycrisp and early Fuji. McIntosh is mature at some farms and close to being mature at others. Growers have been harvesting Gala and a few McIntosh, but the pace of Gala harvest needs to be quickened and Honeycrisp needs a good light first picking at most farms. Early Fuji strains are mature in all blocks tested. Harvest dates are running a few days ahead of the predicted harvest dates.

Size is generally very good this season; fruit color has faded in the last week due to the hot day and night temperatures. Oddly, fruit firmness has increased an average of 1.5 pounds for the three varieties sampled over the last two weeks. Bitter pit has developed in the last 10 days in many Honeycrisp blocks, particularly on the largest fruit growing on the bottom tier of scaffold branches.

Lastly, growers are finding apples are bruising easily during harvest operations this season for these first of the long list of fall apples. It is mainly showing up a day or two after harvest when fruit has set in storage for a day. This bruising is most likely the result of the abundant rains that most growers have had over the past few months.

I have revised the normal and 2015 peak harvest dates for apple varieties in east Michigan (last table in this report) to include many varieties.

Individual variety results

Gala were sampled for the second week of the fall harvest season and have quickly matured in the last week due to the hot weather. Gala is a variety that responds well and matures quickly in hot weather. In the last week, the starch index has leaped an average from 1.6 to 4.1. However, there is a spread in maturity from site to site, with a few farms still being immature and others being over-mature. So, check your site closely. The target index is 3.0 for long-term storage and most likely 4.0 for shorter-term storage and immediate sales. Firmness has increased from 18.1 pounds last week to 19.6 pounds this week and brix has improved to 12.9 percent.

McIntosh were sampled for the second week of the season. They’ve have matured at their normal pace over the last week and are still a bit on the immature side in most blocks. They are still eating on the green side. Some internal ethylene is starting to develop. The predicted harvest date is Sept. 10 for the region, but it may be a few days behind that date. Galas are ahead of McIntosh this season. The color has faded and is generally poor in McIntosh at this time, averaging 40 percent, and firmness has risen from an average of 15 pounds last week to 17.1 pounds this week. The starch removal is fine at 3.8; recall that McIntosh need to be closer to 5 to be considered mature, higher than any other variety. McIntosh need a few more days to mature.

Honeycrisp were sampled for the second week of the season and is the second variety this week to very quickly move from being immature one week to now being ready to begin its first light harvest. This variety is well known for always having a wide range of fruit maturity between individual fruit, and this season it is typical, with well exposed fruit on the outside to the tree coloring well and to eat better than fruit on the inside of the tree, which is green as grass. The starch removal index averaged only 1.5 last week and now averages 5.2 with a brix of 13.5 percent. Ethylene levels in fruit have jumped to 100 percent of the fruit having internal ethylene levels greater than 0.2 parts per million (ppm). The color of the more mature fruit sampled from the outside of the tree is 46 percent and fruit firmness averages 16.2 pounds, up a pound in the last week.

Early Fuji was sampled for the first time of the season, and based on their maturity, should have been sampled last week as they are ripe to over-ripe. The starch index is averaging 6.5 and pressure is averaging 16.6 pounds. There is a good amount of internal ethylene, with 60 percent of fruit having internal ethylene levels greater than 0.2 ppm. They are eating well and need to be harvested soon.

Empire was sampled for the first time of the season to get an early indication of their maturity, and based on these results are still immature. The predicted harvest date is Sept. 16.

Redcort was sampled for the first time of the season to get an early indication of their maturity, and based on these results are still immature. The predicted harvest date is Sept. 23.

Predicted apple harvest dates

Each year we publish predicted harvest dates for three varieties for many locations across the state. This year’s dates were published July 15 on the Michigan State University Extension website, “Predicted 2015 apple harvest dates.” The table below has been expanded this week to include more apple varieties and it lists only one date for the entire region, which is hard to do. The information in “Predicted 2015 apple harvest dates” lists the bloom and harvest dates for Deerfield and Romeo, Michigan. You can adjust your predicted harvest dates based on your bloom dates or make adjusts to this expanded list based on the typical harvest dates at your farm. 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 based on the data I generated from the first few weeks’ samples, I believe your actual harvest dates may be a few days ahead of these predicted harvest dates for most varieties. Time will tell more of this story over the next few weeks, so keep a close eye on the weekly apple harvest updates for possible revisions of these dates.

Looking for more? View Michigan State University Extension’s Apple Maturity 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 tritten@msu.edu, office phone 810-244-8555, cell 810-516-3800 and fax 810-341-1729. Special thanks to four orchards that allow me to harvest fruit for analysis from their farm every Monday during the apple harvest season, these farms include: Spicer Orchards in Hartland, Erwin Orchards in South Lyon, Westview Orchards in Romeo and Hy’s Cider Mill in Romeo. Thanks to so many other orchardists that I collect fruit samples from their farms to include their varieties on more of a random basis. Lastly, thanks to the Post-Harvest Lab in the Department of Horticulture at Michigan State University that provides the quick and very accurate analysis of so many apple samples in the fall. Dr. Randy Beaudry and his students do a fantastic job and are a valuable part of our Apple Maturity Team.