MSU Extension

General apple harvest comments

Most growers are seeing a light at the end of apple harvest over the next two weeks. A few growers are finishing up harvest of Jonagold and Golden Delicious, with most Red Delicious and Fuji being harvested last week in the south and in the last few days to the north. This week’s data shows many blocks of Northern Spy, Crispin and Idared are ready to harvest, as well as lesser-planted acreages of CandyCrisp and Cameo.

This is the sixth apple harvest report for the season; I have collected and analyzed apples for the last seven weeks. This week, 11 apple varieties were sampled and tested for maturity, with Winesap, Enterprise and Braeburn added to the mix. I will be sampling for apple maturity at least one more week, so look for a report next Wednesday, Oct. 19. However, the mix of varieties sampled will be reduced as we move toward to end of harvest.

Again this week, Brix levels took another nice jump from 12.8 percent last week to 13.9 percent this week when averaged over all varieties tested, even including the three to four varieties that are still immature. I am seeing increasing amounts of fruit cracking as we progress with apple harvest. This is due to drought this spring and summer followed by above-normal precipitation for most growers starting in mid-August.

I continue seeing increased numbers of brown marmorated stink bugs in traps as well as limited amounts of fruit damage at almost all apple farms I visited over the last few weeks. Growers should be on the lookout for insects feeding in orchards, particularly on warm afternoons, and damaged fruit as apples are being harvested and graded. Black rot on fruit remains a problem at several farms, much worse in many blocks than the last few seasons. Sooty blotch and flyspeck are showing up more and more on later maturing varieties. Blister spot continues in Crispin.

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

Individual variety results

Jonagold was sampled for the fifth week of apple harvest and sampling was limited to the second picking in just one block, as most blocks of Jonagold were harvested two weeks ago. The predicted harvest date for Jonagold was Sept. 24, and I think that date was very close this season. Jonagold tested this week as over-mature. The percentage of fruit with internal ethylene levels greater than 0.2 ppm remained at 40 percent, with fruit color improving to 87 percent this week. The pressure is still firm at 15.7 pounds and starch index averaging 8.0.

Golden Delicious was sampled for the fifth week of apple harvest; the predicted harvest date was Sept. 30. As with Jonagold, sampling was limited to one block this week as most Golden Delicious blocks were picked last week. For some reason, this strain of Golden Delicious was very slow to mature this season, and it is finally ready to harvest. The following values are hard to compare to last week’s data, as this is just one block and not an average of several blocks as was used for last week’s results.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm actually went down from 20 percent last week to 0 percent or none this week, with fruit color or blush also dropping to 8 percent this week. The pressure is firm at 15.5 pounds and starch index dropped to 3.6 this week. This block had good Brix at 14.6 percent.

Red Delicious was sampled for the fourth week of the season, again the Redchief strain. As with Jonagold and Golden Delicious, sampling was limited to one block as most Red Delicious blocks were harvested last week in the south and in the last few days in the rest of the region. This block of Red Delicious was slow to mature this season, and it is almost ready to harvest. The predicted harvest date for Red Delicious was Oct. 1, which was earlier than most blocks matured. Here again, the following values are hard to compare to last weeks data, as this is just one block and not an average of several blocks as was used for last weeks results.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm dropped from 78 percent last week to 60 percent this week. Color remains good at 94 percent. The pressure remains firm at 16.0 pounds and the starch index also dropped from 4.7 last week to 3.2 this week.

Northern Spy was sampled for the fourth week of apple harvest. Northern Spy has matured quickly in the last few days and are ready for harvest; they are eating very well. The percentage of fruit with internal ethylene levels greater than 0.2 ppm rose from 73 percent last week to 87 percent this week. Fruit color improved to 55 percent and pressure remains firm at 18.7 pounds. The starch index rose sharply this week, from 2.5 last week to 4.0 this week. The Brix also took a good jump to 13.1 percent.

Crispin or Mutsu was sampled for the fourth week of the season. Some Crispin blocks are ready to harvest and others need a few more days to mature. Some Crispin blocks are eating well, and others are on the green side. Some blister spot symptoms appeared in Crispin. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is still low at 23 percent, with fruit color or blush the same at 10 percent. The pressure is firm at 17.3 pounds and average starch index rose from 2.1 last week to 3.4 this week –a nice jump.

Idared was sampled for the third week of the season. The predicted harvest date for Idared was Oct. 6. Like Red Delicious, this variety is maturing after its predicted harvest date. Some blocks of Idared’s are ready for harvest and others need a few more days to mature. The percentage of fruit with internal ethylene levels greater than 0.2 ppm rose sharply from 53 percent last week to 83 percent this week. The fruit color remained constant at 86 percent. The pressure is 15.5 pounds and starch index averaged 2.9, with blocks above 3.5 ready to harvest now.

CandyCrisp was sampled for the third time this apple harvest and is ready to harvest. CandyCrisp is a new variety for many farms. Fruit sampled this week picked easy and may drop if left on the tree much longer. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is still low at 10 percent, with fruit color or blush about this same at 19 percent. The pressure is 16.8 pounds and starch index up just over one point to 3.4.

Fuji was sampled for the third time this season, with a limited number of Fuji blocks to sample because many were harvested late last week. Both Fuji blocks sampled this week are now ready for harvest. The percentage of fruit with internal ethylene levels greater than 0.2 ppm has risen sharply again this week from 43 percent last week to 95 percent this week. Fruit color has improved to 89 percent. The pressure is still firm at 17.1 pounds, with starch index averaged 4.7. As with several other varieties, the Brix took a nice jump to 14.0 percent.

Cameo was sampled for the second time this season, and as with CandyCrisp, this is a new variety for many growers, with limited acreage planted. Cameo is very close to being ready to harvest, maybe needing a few more days to mature. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 50 percent, with fruit color improving from 36 percent last week to 66 percent this week. The pressure is firm at 17.8 pounds and starch index at 3.4.

Winesap was sampled for the first time this season, mainly to get an early read on its maturity. Winesap is still immature and is not ready for harvest; it may be a few weeks still. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 5 percent, with fruit color at 83 percent. The pressure is firm at 16.6 pounds and starch index at 1.0.

Enterprise was sampled for the first time this season. Enterprise is not a widely planted variety in this region, but I had a few requests to sample it this season. I do not have a predicted harvest date for Enterprise, but it will most likely mature just ahead of Braeburn. Enterprise is still immature and not ready for harvest. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 10 percent, with fruit color at 76 percent. The pressure is firm at 18.6 pounds and starch index at 1.2.

Braeburn was sampled for the first time this season, mainly to get an early read on its maturity. The predicted harvest date of Braeburn is Oct. 23. Braeburn is still immature and not ready for harvest, but may be ahead of Winesap this season. I estimate that it may be 10 to 14 days for it to mature. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 60 percent, with fruit color at 59 percent. The pressure is firm at 18.2 pounds and starch index at 2.3.

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.