MSU Extension

General apple harvest comments

McIntosh harvest is nearly complete at most farms; the cooler weather has helped color to return more toward normal. Gala have been mostly harvested, with some of the unharvested blocks being over mature and starting to feel waxy. Honeycrisp are mature and have been spot-picked for the first time and growers are going back for the second picking. Early Fuji was harvested late last week. Some early maturing Jonagold and Jonathan sites are ready for long-term storage and controlled atmosphere (CA) storage harvest, but need more time for fresh and immediate fall sales. Empire, Cortland and Golden Delicious were sampled this week as well and are slowly moving toward maturity.

This week, seven apple varieties were sampled and tested for maturity. Harvest dates for most varieties are running a few days ahead of the predicted harvest dates.

Fruit size is generally very good this season, with the exception of some poorly thinned Jonathan blocks. With cooler nighttime temperatures, fruit color has greatly improved in all varieties in the last week. Interestingly, fruit firmness has remained very good this season for all varieties. The brix or sugar levels have improved almost a full percentage point in the last week. Bitter pit is a problem in many Honeycrisp blocks.

As I reported last week, this season growers are finding apples are bruising easily during harvest operations. 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 third week of the fall harvest season and are now testing to be over-mature, with some waxy feel to the fruit starting to be found. Gala is a variety that responds well and matures quickly in hot weather. In the last week, the starch index has moved an average from 4.1 to 5.9. The target index is 3.0 for long-term storage and most likely 4.0 for shorter-term storage and immediate sales. Fruit firmness has dropped just a bit from 19.6 pounds last week to 19.3 pounds this week and brix has improved almost 1 percent to 13.8 percent.

McIntosh were sampled for the third week of the season, most blocks were color picked early to mid-last week and are now in their final picking. They have matured at their normal pace over the last week and are eating much better. More internal ethylene is developing, now with 20 percent of fruit being over 0.2 parts per million (ppm). The predicted harvest date was Sept. 10 for the region. Fruit color has improved from 40 percent last week to 68 percent this week. Fruit firmness has dropped from an average of 17.1 pounds last week to 16.4 pounds this week. The starch removal is up from 3.8 last week to 5.2 this week; recall that McIntosh need to be closer to 5 to be considered mature, higher than any other variety. The brix is now at 13.2 percent.

Honeycrisp were sampled for the third week of the season and has been spot-picked at least once and on many farms is being spot-picked now for the second time. Bitter pit is a problem in many Honeycrisp blocks; several growers have pushed harvest ahead to reduce the problem. I generally recommend three to four pickings of Honeycrisp to obtain maximum fruit quality. So, the fruit I sampled in previous weeks was already harvested when I collected this week’s samples. I always look to pick the most mature fruit from the outside of the tree for my Apple Maturity Project samples. So it is hard some weeks to use this data as I am sampling the next picking of Honeycrisp. 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 eating better than fruit on the inside of the tree, which is still green.

The starch removal index averaged 5.3 last week and is now 6.1 this week. The brix is 13.6 percent. Ethylene levels in fruit have remained high with 93 percent of the fruit having internal ethylene levels greater than 0.2 ppm. The color of the more mature fruit sampled from the outside of the tree is 47 percent and fruit firmness averages 16.9 pounds.

Early Fuji was sampled for the second time of the season, and based on their maturity this week, are now over-mature. The starch index is averaging 6.6 and pressure is averaging a firm 18.4 pounds. There is a good amount of internal ethylene, with 70 percent of fruit having internal ethylene levels greater than 0.2 ppm. Brix has improved almost a full percent to 13.5 percent. They are eating a bit on the over-mature side and need to be harvested soon.

Empire was sampled for the second week of the season and based on the data from this week, they are still immature. While the predicted harvest date is Sept. 16, this is one variety that is bucking the trend of varieties being mature a few days ahead of these predicted harvest dates. I think they need at least another week before they are mature, even for long-term and CA storage.

Redcort or Cortland was sampled for the second time and based on this week’s data are still immature. The predicted harvest date is Sept. 23. Based on this week’s data, Redcort may take longer to mature this season.

Jonathan was sampled for the first time of the season to get an early indication of their maturity, and based on these results I wished that I had started sampling Jonathan last week. Some blocks are still very green with a starch index of 1.6 and other locations are testing a starch index as high as 5.1, indicating they are ready for harvest. The predicted harvest date is Sept. 25. Growers need to keep a close eye on Jonathan maturity.

Jonagold was sampled for the first week of the season to get an early indication of their maturity, and like Jonathan, I should have sampled Jonagold last week as well. I took a good number of Jonagold samples from several orchards across the region. The predicted harvest date for Jonagold is Sept. 25. Some blocks are still green with a starch index of 2.2 and other locations are testing a starch index as high as 5.8, indicating they are ready even for short-term harvest. Growers need to keep a close eye on Jonagold maturity this season. Lastly on Jonagold, many blocks had severe winter injury from extreme cold in the winter of 2013-14 with resulting injury to main scaffold branches and trunks and lots of tree death. While some trees did survive this cold, trees were injured and thus may be maturing earlier than normal.

Golden 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.

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 three weeks’ of samples, 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.