MSU Extension

General apple harvest comments

Apple growers have been moving quickly through harvest of many varieties this past week. Most growers report they are about three-quarters complete with harvest, and in a week or so they may be wrapping things up for harvest. Harvest dates for most varieties are running a few days ahead of the predicted harvest dates.

Fuji has matured very fast over the last week and has jumped ahead of several other varieties in terms of their maturity. Growers need to check them soon if they have not done so in the last few days.

Growers have been picking Red Delicious and Northern Spy, spot-picking Ida Red and now Fuji and Law Rome’s are ready. Crispen and Braeburn are moving toward maturity, and Winesap seems to be lagging behind this season.

This week, 10 apple varieties were sampled and tested for maturity in east Michigan, with Braeburn being added to the mix this week to get an early read on its maturity. I did sample one block of Gibson Golden Delicious this week – note that it is not included in the following table. This strain seems very slow to mature this season. Most Golden blocks have been harvested in the last week.

Fruit size remains good this season, but the bins don’t seem to be filling as much as most growers anticipated. Fruit firmness or pressure has remained firm and brix has improved over the last week.

Blister spot is being found in many Crispen blocks. Black rot on fruit remains a problem at several farms. Woolly apple aphid populations are very high in many apple blocks. Sheet scab is starting to show up in many apple blocks.

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

Red Delicious was sampled for the fourth week of the season. Many Red Delicious blocks have been harvested, so the sample size for this week’s data was therefore reduced. Maturity has moved along well in the last week. Reds have sized very well the past three weeks and are eating much better. The percentage of fruit with internal ethylene levels greater than 0.2 parts per million (ppm) has moved from 72 percent last week to 100 percent this week. Fruit have remained fairly firm at 16.1 pounds; fruit color has improved to 89 percent. The starch index has moved from an average of 3.6 last week to 5.0 this week. Many blocks are over-mature if they are intended for long-term or CA storage.

I sampled three stains again this week, Redchief, Miller Spur and Ace. This week, Redchief remains ahead of the other two in terms of overall maturity with Miller Spur being more mature than Ace. Site and crop load are generally greater factors in maturity than the strain. The predicted harvest date for east Michigan for this variety was Oct. 3, which was very close.

Ida Red was sampled for the fourth time of the season and based on this week’s data, the harvest window is now opening for Ida Red. The percentage of fruit with internal ethylene levels greater than 0.2 ppm has jumped from 65 percent last week to 93 percent this week. The predicted harvest date for Idared was Oct. 8 for east Michigan, so it is maturing much later than predicted this season.

Northern Spy was sampled for the fourth week of the season. Many blocks have been picked in the last week, so my sampling was shifted to different blocks this week. Most blocks are mature. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is now at 100 percent. The predicted harvest date for Northern Spy was Oct. 10 for east Michigan, so they were generally ahead of this date.

Fuji was sampled for the third week of the season and based on this week’s data, fruit have matured quickly over the past week as all blocks are ready to harvest. The data from this week is very similar for all Fuji blocks tested. I need to clarify that the starch index average of 5.2 for the Sept. 28 sample date may not have been read correctly by the Post-Harvest Lab at MSU, as Fuji’s clear their starch much differently than any other variety. The percentage of fruit with internal ethylene levels greater than 0.2 ppm has moved from 70 percent last week to 85 percent this week. The starch index has leapt from an average of 3.6 last week to 6.5 this week. The predicted harvest date for Fuji is Oct. 23 for east Michigan; most blocks are ready 10 days ahead of this date.

Cameo was sampled for the third time of the season and appears to be maturing very slowly this year; based on this week’s data they are still immature. We don’t have as much experience with this newer variety to get a good read on its maturity patterns. The predicted harvest date for Cameo was Oct. 14 for east Michigan.

Crispen (Mutsu) was sampled for the third week of the season, and based on this week’s data are still immature. The predicted harvest date for Crispen is Oct. 18 for east Michigan. It appears they will be ready to harvest after that predicted harvest date.

Law Rome was sampled for the second week of the season and based on this week’s data, most blocks are ready to begin harvest. I have not found any internal red staining. The predicted harvest date for Law Rome was Oct. 13 for east Michigan, so we were close to that date.

Winesap was sampled for the second week of the season, and based on this week’s data are still immature. The predicted harvest date for Winesap is Oct. 19 for east Michigan; I don’t think they will be ready by then however.

Braeburn was sampled for the first week of the season to get an early indication of its maturity, and based on this week’s data are still immature. The predicted harvest date for Braeburn is Oct. 24 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 seven 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.