MSU Extension

General apple harvest comments

Most growers report they are just beyond the midpoint of apple harvest. Growers have finished up Empire and have started Golden Delicious, Northern Spy and some early maturing Red Delicious sites. While Ida Red and Fuji are not mature yet, growers are keeping a close eye on their maturity.

This week, 11 apple varieties were sampled and tested for maturity, with Law Rome and Winesap being added to the mix to get an early read on their maturity. I did not sample Jonagold this week as it is over-mature. Harvest dates for most varieties are running a few days ahead of the predicted harvest dates.

Fruit size remains good this season with many Red Delicious blocks taking on a good swell in the past two weeks. The possible exception is some Red Delicious blocks that were not thinned well early this summer. Fruit firmness or pressure has remained firm and brix has stayed about the same in most varieties 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.

I continue to get reports about how easily fruit is bruising this season. However, this past week it seems to be less of an issue. 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 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 fifth week of the season with just a few blocks still unharvested. Empire was unusually slow to mature this season, but this last week it’s maturity moved along quickly, with fruit left to sample now being over-mature. Fruit firmness dropped 4.0 pounds to 14.7 pounds over the last week and the starch is averaging 7.3. The predicted harvest date for Empire was Sept. 16; it matured well after this date. This is one variety that bucked the trend of most varieties being mature before their predicted harvest date.

Golden Delicious was sampled for the fourth week of the season. Many of the blocks I have been sampling for the last three weeks have been harvested, so this week’s samples are either other strains of Goldens (I have been sampling Smoothee) or I sampled less mature fruit that was left on the tree longer to mature for a second picking. So, while the starch index appears to have gone down this week, moving from 4.3 last week to 3.3 this week, it actually is the case that I am sampling less mature fruit. The percentage of fruit with internal ethylene levels greater than 0.2 parts per million (ppm) has jumped from 5 percent last week to 40 percent this week. The Goldens that are left are still eating well and are very sweet. Goldens matured a few days ahead of the Oct. 2 predicted date for east Michigan.

Red Delicious was heavily sampled again this week. This is the third week of sampling Red Delicious for the season. Some early maturing strains and sites have been harvested this week. Reds have sized very well the past two weeks and are eating much better this week. The percentage of fruit with internal ethylene levels greater than 0.2 ppm has jumped from 33 percent last week to 72 percent this week. Fruit have remained firm at 17.7 pounds; color remains good at 79 percent. Fruit that is intended for long-term and CA storage needs to be harvested soon.

I sampled three stains again this week: Redchief, Miller Spur and Ace. This week, Redchief moved ahead of the other two in terms of overall maturity. Site and crop load are generally greater factors in maturity than the strain. Growers need to keep a close eye on Red Delicious maturity again this week. The predicted harvest date for east Michigan for this variety was Oct. 3, which was very close.

Ida Red was sampled for the third time of the season and based on these results are close to being ready to pick, but still need a bit more time to mature. Some blocks are close to being ready to harvest, possibly being ready later this week or over the weekend. The percentage of fruit with internal ethylene levels greater than 0.2 ppm has jumped from 33 percent last week to 65 percent this week. One oddity in this week’s data is that the starch index has gone backward from 3.0 last week to 2.5 this week. The predicted harvest date for Ida Red is Oct. 8 for east Michigan, so the date will be close.

Northern Spy was sampled for the third week of the season. Some blocks have been spot-picked in the last few days and a few others have been harvested. Some blocks are still immature. The percentage of fruit with internal ethylene levels greater than 0.2 ppm has moved from 63 percent last week to 93 percent this week. Fruit color has also improved. As with Ida Reds, the starch index has also moved back form 4.0 last week to 3.5 this week. However, some of the step back in starch index is the fact that some of the blocks tested last week have been harvested. The predicted harvest date for Northern Spy is Oct. 10 for east Michigan, so they are generally ahead of this date.

Fuji was sampled for the second week of the season and based on this week’s data most blocks are still immature. They eat better than last week, but are still on the green side. I need to clarify that the starch index averaged 5.2 last week, this week dropping back to 3.6. Last week’s starch index figures may not have been read correctly by the MSU Post-Harvest Lab, 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 jumped from 3 percent last week to 70 percent this week. Fruit color has also improved to 55 percent. The predicted harvest date for Fuji is Oct. 23 for east Michigan. I think most blocks need another seven to 10 days for them to mature.

CandyCrisp was sampled for the second time of the season, and based on this week’s data are very close to being mature. CandyCrisp maturity is generally in the same harvest window as Red Delicious.

Cameo was sampled for the second time of the season, and based on this week’s data are still immature. The predicted harvest date for Cameo is Oct. 14 for east Michigan.

Crispen (Mutsu) was sampled for the second 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.

Law Rome was sampled for the first time 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 Law Rome is Oct. 13 for east Michigan, which is a week away. I think we will be close to that date.

Winesap 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 Winesap is Oct. 19 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 six 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.