MSU Extension

General apple harvest comments

With the heat of this summer, we are finding that apples in this early harvest window (Gala, McIntosh, Honeycrisp and Early Fuji) are maturing a few days ahead of the predicted harvest dates that were published earlier this summer on the Michigan State University Extension website. These predicted harvest dates are listed at the end of this report. I encourage apple growers to spend some time in the orchard as soon as possible evaluating the maturity of your apple crop to make sure you are on top of apple harvest.

Based on data from a complete set of apples that were collected on Monday, Sept. 5, and analyzed yesterday, Sept. 6, early maturing strains and sites of Gala, McIntosh and Honeycrisp are ready to be spot-picked. The Honeycrisp data is very surprising to me. More details on each of these varieties and others follow in the individual variety results section.

Apple bloom was very long this spring, meaning apples were not pollinated over a typical short time period of a few days. Thus, we have individual apples on the tree that vary greatly in their maturity. This spread in maturity will be hard to work around this fall. So, growers will find that some apples in the bin will be over-mature and others will be green.

Additionally, most growers have had a long extended period of drought this spring and summer, with plenty of moisture since mid-August. Overall fruit size is down a bit, but not nearly as bad as I had expected if the drought had continued much longer. As mentioned earlier, this has been a very hot season as well. Most of our MSU Enviro-weather stations are recording degree-day totals that are more than 14 or more days ahead of normal. With the drought and heat of this season, it has pushed apple harvest ahead by five days or so, at least for these early harvest window varieties.

Fruit color is generally better than average thus far this fall, but with hot temperatures returning the last few days, color may bleach out a bit. Harvest labor is short at most farms as we begin to ramp up apple harvest.

While this is the first apple harvest report for the season, I have collected and analyzed apples for the last two weeks. This week, five apple varieties were sampled and tested for maturity, with Early Fuji and Empire added to the mix.

Black rot on fruit remains a problem at several farms, much worse in many blocks than the last few seasons. Bitter pit is being seen in many Honeycrisp blocks. While water core was a serious problem in Paula Reds, it appears we are not finding it in other varieties.

The revised normal and 2016 peak harvest dates for apple varieties in east Michigan table continues to be included at the end of this report.

Individual variety results

Gala was sampled for the second week of the season, with several strains tested each week. The predicted harvest date for Gala was Sept. 5, but based on last week’s data I could see it was maturing earlier than this date. This week's data shows early maturing strains and sites are testing that it is mature, and a few sites tested to be over-mature. Gala likes a hot August, and in these conditions tends to mature early. One block that I sampled had a few fruit that had a “greasy” feel, indicating over-mature as well.

Internal ethylene at levels greater than 0.2 parts per million (ppm) rose from 28 percent last week to 100 percent this week. Fruit are still firm at 22.2 pounds and the starch index has jumped from 2.4 last week to 4.4 this week. Growers will need to do a block-by-block sampling to determine which are mature, and in most cases do a spot picking to get the earliest maturing fruit off the tree.

McIntosh was sampled for the second week of the season. The predicted harvest date for McIntosh is Sept. 7, but based on last week’s data I could see it was maturing earlier than this date. As in the case of Gala, early maturing strains and sites are testing that it is mature. Growers will need to do a block-by-block sampling to determine which are mature, and in most cases do a spot-picking to get the earliest maturing fruit off the tree. There is some fruit drop in McIntosh, but most of the fruit has been pushed off the limb from growth rather than dropped on its own accord.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm has rose from 8 percent last week to 33 percent this week. Fruit color remained about the same at 48 percent and the starch index has risen from 3.1 last week to 4.2 this week. The brix is still low at 10.9 percent. Some McIntosh blocks still eat green, but many have fruit that is ready for harvest.

Honeycrisp was heavily sampled this week; this is the second week of sampling Honeycrisp. Recall that when we take a sample of any variety, we take the most mature fruit. So in the case of Honeycrisp, this is the few fruit per tree that have a bright red color (what I call “stop light” color) with the background color changing to yellow. The predicted harvest date for Honeycrisp is Sept. 11, but based on this week's data it has moved very quickly in the past week. It was amazing to see how quickly Honeycrisp have moved in just one week. As in the case of Gala and McIntosh, early maturing strains and sites are testing that it is mature. Growers will need to do a block-by-block sampling to determine which are mature, and do a light spot picking to get the earliest maturing 5 to 20 percent of the stop light colored fruit off the tree. Honeycrisp always require three to four pickings. The fruit that is ready is eating well.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm has jumped from 5 percent last week to 85 percent this week. Fruit have remained firm at 18.6 pounds; color remains fair at 46 percent. The starch index jumped from 2.0 last week to 5.3 this week, with a few blocks testing over-mature. Fruit that is intended for long-term and controlled atmosphere storage needs to be harvested now.

Early Fuji was sampled for the first week of the season and based on these one-week results, a few blocks are ready to be picked, but most still need a bit more time to mature. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 50 percent, with an average starch index of 3.8. The predicted harvest date for Early Fuji is Sept. 10 for east Michigan, so the date appears to be a few days earlier, but very close.

Empire was sampled for the first week of the season, mainly to get an early read on its maturity. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 7 percent, with fruit color at 53 percent. The pressure is firm at 21.0 pounds and starch index at 1.8. They are eating green, but better than I thought they would for this time of fall. Maybe Empire is maturing at its normal pace this season; time and a few weeks of data will tell more of the story.

Predicted apple harvest dates

Each year we publish predicted harvest dates for three varieties for many locations across the state. This year's “Predicted 2016 apple harvest dates” were published July 11. 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 2016 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. I believe our actual harvest dates may be a few days ahead of these predicted harvest dates for most varieties. 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 in Flint, Michigan. Email: tritten@msu.edu; Office phone: 810-244-8555; Cell: 810-516-3800; and Fax: 810-341- 1729. Special thanks to the four orchards that allow me to harvest fruit for analysis every Monday during the apple harvest season: 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 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. Randy Beaudry and his students do a fantastic job and are a valuable part of our Apple Maturity Team.