MSU Extension

General apple harvest comments

Growers are harvesting Gala and Honeycrisp and finishing up on McIntosh. Based on testing of apples that were harvested Monday, Sept. 11, and analyzed yesterday, Sept. 12, Jonagold are also mature.

This is the third Michigan State University Extension apple harvest report for the season. I have collected and analyzed apples for the last four weeks. This week, eight apple varieties were sampled and tested for maturity with Jonathan, Jonagold, Cortland and Golden Delicious being added to the list this week.

Remember that our bloom period this spring was early and extended for three to four weeks, meaning apple maturity is ahead of most growing seasons and the fruit pollinated over the almost four weeks will be maturing over the same length of time. This means multiple pickings on most varieties.

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. The predicted harvest dates are listed at the end of this article.

Fruit color has been generally better than average this fall for most varieties. Many green skinned apple varieties, like Golden Delicious and Crispin, have a nice blush on them this season. Fruit pressure was higher than last week on all varieties tested over the last few weeks. This is mainly due to sampling different or less mature blocks, as more mature fruit is harvested and cooler temperatures over the last few weeks. The brix levels have risen a full percentage point over the last week.

The crop is generally picking out shorter than most growers predicted. Many farms have added more harvest labor over the last few weeks, combined with the short apple crop, and most farms now have enough harvest labor.

In the last few days, I have seen a spike in brown marmorated stink bug adults and nymphs in traps. This may be due to soybean fields and other host plants beginning to dry down, thus these plants are less attractive to brown marmorated stink bug feeding. I continue to see limited amounts of fruit damage at many apple farms I have visited over the last month. Be on the lookout for the brown marmorated stink bug 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 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 forth week of the season, and finally over the last week maturity has moved quickly to a point where Gala are ready to harvest. A few of the fruit I tested this week had that waxy or overripe feel to them. The predicted harvest date for Gala was Sept. 3, but based on data over the last four weeks, it has become clear that due to our cool season, they have been very slow to mature this season. Gala maturity was well behind McIntosh this season.

Fruit color and size have been very good this year, except where soils were dry fruit size is reduced. Fruit are still very firm at 22.9 pounds and the starch index has moved from 2.3 last week to 4.9 this week.

McIntosh was sampled for the fourth week of the season and their maturity has moved steadily along. The predicted harvest date for McIntosh was Sept. 4, but it matured earlier than this date. Most blocks have been harvested, so it was harder to find blocks this week to sample and test. Growers have been picking Macs for the last two weeks and have been holding off on some of the remaining unharvested blocks waiting for better color—most are on older trees.

The starch index rose from 4.3 last week to 5.6 this week. There has been more fruit drop in McIntosh over the last week, but most of the fruit has been pushed off the limb from growth rather than dropping on its own accord.

Honeycrisp was sampled for the fourth week of the season. Most blocks have been picked two or three times in the last week, so the data in the table below for this week is skewed to the fruit that remains on the interior of the tree. Growers have been waiting for this more interior fruit to color and size before picking. Once Honeycrisp reach a certain stage of maturity, they tend to hold well on the tree. I think we at this point for Honeycrisp. However, watch for off flavors to develop.

The predicted harvest date for Honeycrisp was Sept. 12, but based on last week's data it was ready several days ahead of this date. Honeycrisp destined for longer-term storage needs to be preconditioned between 50 and 68 degrees Fahrenheit for five to seven days before refrigeration to help avoid storage disorders.

Empire was sampled for the second week of the season and is not ready for harvest. The average starch index moved from 2.2 last week to 3.0 this week. Color has improved this week to 57 percent. The predicted harvest date for Empire is Sept. 17 for east Michigan, but I think they will be ready to harvest a few days ahead this date.

Jonathan was sampled for the first week of the season to get an early read on its maturity. Based on these one-week results, they are not ready to begin harvest. The average starch index is 1.7. The predicted harvest date for Jonathan is Sept. 18 for east Michigan, which is five days from today. I think it may take a few days longer than this for Jonathan to mature. They are still eating green.

Jonagold was sampled for the first week of the season to get an early read on its maturity. Based on these first week results, it is surprisingly ready to harvest now. The average starch index is 5.9. The predicted harvest date for Jonagold is Sept. 18 for east Michigan, which is five days from today. Sample Jonagold blocks today to check maturity.

Cortland 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. The average starch index is 2.3. The predicted harvest date for Cortland is Sept. 20 for east Michigan, which is seven days from today. I think this date will be close.

Golden Delicious was sampled for the first week of the season to get an early read on its maturity. Based on these first week results, it is not ready to begin harvest. The average starch index is only 1.3. The predicted harvest date for Golden Delicious is Sept. 25 for east Michigan, which is 12 days from today. Let’s see what next week’s data looks like to dial in this harvest date.

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” was 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.