MSU Extension

General apple harvest comments

The pace of apple harvest has picked up considerably in the last week. Growers are harvesting McIntosh, spot-picking a few early strains and sites of Gala and are just beginning to do a first light harvest of Honeycrisp. Based on testing of apples that were harvested on Monday, Sept. 4, and analyzed yesterday, Galas are maturing well behind McIntosh this season.

This is the second apple harvest report for the season; I have collected and analyzed apples for the last three weeks. This week, five apple varieties were sampled and tested for maturity, with Empire being added to the list this week.

As I shared last week, our bloom period this spring was both early and extended for three to four weeks; meaning apple maturity is ahead of most growing seasons and fruit was not pollinated over a typical short time of a few days. Further, our growing season has been running three to six days ahead of normal for most of the summer. Thus the predicted harvest dates reflect these factors. However, based on the maturity of McIntosh, Honeycrisp and Early Fuji, our harvest windows are tending to run a few days even earlier than the predicted harvest days for most varieties, with the exception of Gala. These predicted harvest dates are listed at the end of this article. I encourage apple growers to spend time in their orchards to evaluate the maturity of their own apple varieties.

Again, apple bloom was very long this spring. 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.

Fruit color has been generally better than average for most varieties for the last four weeks. Harvest labor is short at most farms as we begin to ramp up apple harvest.

Lastly, when I take a sample for testing of any variety, for example Honeycrisp, I always pick the fruit that is the ripest or most mature. So in the case of Honeycrisp, this is the fruit that has a bright red color (what I call “stop light” color) with the background color changing to yellow. By choosing the most mature fruit for testing, this hopefully will give you a heads up as to when fruit is approaching maturity.

I continue to see increased numbers of brown marmorated stink bug (BMSB) adults and nymphs in traps as well as limited amounts of fruit damage at many apple farms that I have visited over the last three weeks. Growers need to continue to be on the lookout for this stink bugs’ feeding in orchards, particularly on warm afternoons, and for damaged fruit as apples are being harvested and graded.

Black rot on fruit remains a problem at several farms and is much worse in many blocks than the last few seasons. Sooty blotch and flyspeck are showing up more and more on later maturing varieties.

The table with the normal and 2017 peak harvest dates for apple varieties in east Michigan is included at the end of this report.

Apple maturity at a glance

Individual variety results

Gala was sampled for the third week of the season, with several strains tested each week. The predicted harvest date for Gala was Sept. 3, but based on data over the last three weeks I think it will actually be a few days later. Gala maturity is well behind McIntosh this season. My experience with Gala is that it matures slowly in cooler seasons, like this one. Fruit are still firm at 20.6 pounds and the starch index has moved from 1.9 last week to 2.3 this week. Dry conditions in many areas have slowed fruit sizing, but color is generally very good. Where soil moisture has been adequate this season, fruit size is exceptional. Growers will need to do a block-by-block sampling to determine which stains and sites are mature, and in most cases will need to do a spot picking to get the earliest maturing fruit off the tree.

McIntosh was sampled for the third week of the season. The predicted harvest date for McIntosh was Sept. 4, but it matured earlier than this date. Growers have been picking Macs last week and this week. Some blocks have great color (for Macs); others may need a few cooler nights for better color. The starch index has risen from 1.6 two weeks ago, to 3.6 last week and this week to 4.3. Macs are eating very well this week. Here again, growers will need to do a block-by-block sampling to determine which are mature. There has been 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.

Honeycrisp was sampled for the third week of the season. The predicted harvest date for Honeycrisp is Sept. 12, but based on this week's data and sampling a lot of them, it has moved nicely in the past week. In the last few days many growers are just starting a light first picking of Honeycrisp. A light picking 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. Again, growers will need to do a block-by-block sampling to determine which strains and sites are mature, and do a very light first 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 color has greatly improved in the past week, and starch index has now moved nicely from 3.3 last week to 3.7 this week, in to the mature range. The fruit that is ready is eating well.

Early Fuji was sampled for the second week of the season and based on these results, are ready to be picked to being over mature. The average starch index has moved from 5.6 last week to 6.1 this week. The predicted harvest date for Early Fuji is Sept. 7 for east Michigan, so this variety matured ahead of this date.

Empire was sampled for the first week of the season to get an early read on its maturity. Based on these one-week results, it is not ready to begin harvest yet. The average starch index is 2.2. The predicted harvest date for Empire is Sept. 17 for east Michigan, which is 11 days from today.

Predicted peak fresh market apple harvest dates

Each year we publish predicted harvest dates for three varieties for many locations across the state. This year's “Predicted 2017 apple harvest dates” were published July 25. The table below has been expanded to include more apple varieties and it lists only one date for the entire east Michigan region, which is hard to do! The information in the “Predicted 2017 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 will be affected by the apple strain, rootstock, crop load, fertility, soil type, and other factors including current weather. 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 three 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 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.