MSU Extension

General apple harvest comments

McIntosh harvest is wrapping up at most farms this week and growers are continuing to harvest Honeycrisp, some for the final time. Jonagold maturity is well ahead of Jonathan this season, with many Jonagold blocks being harvested. A few Jonathan blocks are being harvested as they are eating much better this week. A few early maturing blocks of Golden Delicious are being harvested that are going into long-term and CA storage. Empire and Cortland are slowly moving toward maturity, but are not ready yet. Red Delicious, Idared and Northern Spy were added to the sampling this week to get an early read on their maturity, all are still very green.

This week, eight apple varieties were sampled and tested for maturity. I no longer sampled Gala, McIntosh or Honeycrisp as all three are mature. Harvest dates for most varieties are running a few days ahead of the predicted harvest dates.

Fruit firmness or pressure has dropped by several pounds in many varieties in the last week. Fruit size remains good this season. I am surprised that even with cooler nighttime temperatures, fruit color has not improved in the last week. In fact, color has gotten poorer week. Generally, the brix or sugar levels have slightly improved in the last week. Bitter pit remains a problem in many Honeycrisp blocks and I am starting to see it in Jonagold.

As I reported two weeks ago, this season growers are finding apples are bruising easily during harvest operations. It is mostly showing up a day or two after harvest when fruit has been 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

Empire was sampled for the third week of the season and based on the data from this week, a few blocks are very close to being mature and harvest can start later in the week. However, most blocks need more time to mature. While the predicted harvest date for Empire was Sept. 16, they are very slow to mature this season. As you can see from the following table, fruit firmness has dropped over 3 pounds in just one week, but this is still above the 16-pound minimum firmness needed for long-term and CA storage.

Redcort or Cortland was sampled for the third time this season and based on this week’s data, most blocks are still immature. The predicted harvest date is today, Sept. 23. Based on this week’s data, Redcort is very slow to mature this season. Fruit firmness dropped over 2 pounds for this variety in the last week.

Jonathan was sampled for the second time of the season. Some blocks are being harvested where the starch index is 4.6; however, most blocks are still green with a starch index of 2.0. The predicted harvest date is Sept. 25. Growers need to keep a close eye on Jonathan maturity as the fruit firmness dropped just over 3 pounds in the last week.

Jonagold was sampled for the second week of the season and are well ahead of Jonathan at almost all farms. While the predicted harvest date for Jonagold is Sept. 25, they are maturing earlier than this date. All blocks tested are mature with a starch index of 4.7 and a few are over mature with a starch index of 7.1. Growers need to keep a close eye on Jonagold maturity this season.

Golden Delicious was sampled for the second time of the season and while most blocks tested to be immature, a few are nearing being ready to harvest for long-term and CA storage. Most blocks need a few more days to mature. Golden Delicious may be mature before Empire and Redcort this season. It appears that Golden Delicious are running ahead of the predicted harvest date of Oct. 2 for east Michigan for long-term and CA storage.

Red Delicious 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 for this variety is Oct. 3 for east Michigan. I will need another week’s data to see how close we are to this date.

Idared 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 for Idared is Oct. 8 for east Michigan.

Northern Spy 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 for Northern Spy is Oct. 10 for east Michigan.

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 to include more apple varieties and it lists only one date for the entire region, which is hard to do. The information in the “Predicted 2015 apple harvest dates” article 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 adjustments to this expanded list based on the typical harvest dates at your farm. These predicted 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 four weeks’ of sampling, I believe our 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.