MSU Extension

General apple harvest comments

With good weather over the last two weeks, most growers report they are at the midpoint of apple harvest. Growers have finished up Jonathan and Cortland harvest and have moved on to Jonagold, Empire and early maturing Golden Delicious blocks. Northern Spy and some early maturing Red Delicious blocks are mature at some farms as well.

This week, 10 apple varieties were sampled and tested for maturity. Fuji, CandyCrisp, Cameo and Crispen were added to the sampling this week to get an early read on their maturity. I did not sample Cortland or Jonathan this week as both are mature. Harvest dates for most varieties are running a few days ahead of the predicted harvest dates.

Fruit firmness or pressure has maintained about the same over the past week, and brix has improved in most varieties. Fruit size remains good this season, with the possible exception of some Red Delicious blocks that were not thinned well. Bitter pit is a problem in many Jonagold blocks and blister spot is being found in many Crispen blocks. Woolly apple aphid populations are very high in many apple blocks.  

I continue to get reports about how easily fruit is bruising this season. It is mostly showing up a few days after harvest when fruit has been in storage. This bruising is most likely the result of the abundant rains that most growers have had over the past few months.

The revised normal and 2015 peak harvest dates for apple varieties in east Michigan table continues to be included at the end of this report.

Individual variety results

Empire was sampled for the fourth week of the season and based on the data from this week, most blocks are now finally ready to begin harvest. Empire was unusually slow to mature this season. Fruit firmness has remained firm at 18.7 pounds and the starch is averaging 4.0, with brix rising over 1 percent. Fruit color has greatly improved this past week, averaging 80 percent red. They are eating much better this week. The predicted harvest date for Empire was Sept. 16, but this is one variety that matured well after this date.

Jonagold was sampled for the third week of the season. While most blocks were ready to harvest last week, all are now ready and some are over mature.  The predicted harvest date for Jonagold was Sept. 25, they matured earlier than this date.

Golden Delicious was sampled for the third time of the season and most blocks matured quickly in the past week, with the starch moving from 2.6 last week to 4.3 this week. Goldens are maturing a few days ahead of the Oct. 2 predicted date for east Michigan.

Red Delicious was heavily sampled this week; this is the second week of sampling Red Delicious this season. Some early maturing strains and sites are ready to harvest. The color and brix have improved this week and the starch index has jumped from an average of 2.1 last week to 4.1. I sampled three stains, Redchief, Miller Spur and Ace. While Ace tested to be a day ahead Redchief, and Redchief a day or two ahead of Miller Spur, all strains of Red Delicious mature within a few days of each other. Site and crop load are generally bigger factors in maturity than the strain. Growers need to keep a close eye on Red Delicious maturity this week. The predicted harvest date for east Michigan for this variety is Oct. 3, which will be very close.

Idared was sampled for the second time of the season and based on these results are still immature. Some blocks are less than a week from being mature. The predicted harvest date for Idared is Oct. 8 for east Michigan, but most Idared blocks will be mature before this date.

Northern Spy was sampled for the second time of the season and based on these results, some blocks are ready to begin harvest and others are still immature. The starch has jumped from an average of 1.6 last week to an average of 4.0 this week. The predicted harvest date for Northern Spy is Oct. 10 for east Michigan.

Fuji was sampled for the first time of the season to get an early indication of its maturity, and based on these results are still immature. They eat very green yet. I need to qualify that the starch index averaging 5.2 may not have been read correctly by the Post-Harvest Lab at MSU, as they clear their starch much differently than any other variety. So, I need to look at another week of data next week to get a more accurate read on its maturity. The predicted harvest date for Fuji is Oct. 23 for east Michigan.

CandyCrisp was sampled for the first time of the season to get an early indication of its maturity, and based on these results are still immature. I believe that it will be mature in five to seven days, in the Red Delicious maturity window.

Cameo was sampled for the first time of the season to get an early indication of its maturity, and based on these results are still immature. The predicted harvest date for Cameo is Oct. 14 for east Michigan.

Crispen (Mutsu) was sampled for the first time of the season to get an early indication of its maturity, and based on these results are still immature. The predicted harvest date for Crispen is Oct. 18 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 the last five 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.