MSU Extension

General apple harvest comments

This will be the final apple harvest report for the season, as most growers are looking to finish apple harvest over the next week or so. Fuji harvest is ongoing, as is harvest of Northern Spy, Idared, Crispin and Cameo. Some blocks of Braeburn and Enterprise are ready for harvest this week, as are Autumn Gala. Winesap is still immature.

This is the seventh apple harvest report for the season; I have collected and analyzed apples for the last eight weeks. This week’s sampling is winding down, with seven apple varieties sampled and tested for maturity; Autumn Gala was added to the mix.

For the last three weeks I have seen fruit damaged from brown marmorated stink bug feeding. This week, I found fewer insects in traps. Growers should be on the lookout for the insects 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, 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

Crispin or Mutsu was sampled for the fifth week of the season. Most Crispin blocks have been spot-picked and many have been completely harvested. This week’s sample size is limited and most of this sample was been spot-picked already, so the remaining fruit is less mature. Most Crispin blocks are eating well and are ready to harvest. Blister spot was a problem in many Crispin blocks.

The percentage of fruit with internal ethylene levels greater than 0.2 parts per million (ppm) is still low at 0 percent or none, with fruit color or blush taking a nice jump to 31 percent. The pressure is still firm at 16.2 pounds and average starch index went done to 1.8, but remember this is a limited sample size and is the second picking, or fruit that is less mature.

Idared was sampled for the fourth week of the season. The predicted harvest date for Idared was Oct. 6. Like Red Delicious, this variety matured after its predicted harvest date. All blocks tested this week are ready for harvest, and a few are slightly on the over-mature side.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm is the same as last week at 83 percent. The fruit color remained nearly constant at 89 percent. The average pressure is 14.6 pounds, with some blocks being softer than I would like to see. The starch index averaged 4.3.

Cameo was sampled for the third time this season, and this week’s sample was from another farm, so the data is hard to compare from week to week. Cameo is a new variety for many growers, with limited acreage planted. Some farms have harvested Cameo while others are waiting for a few days for them to mature. That is the case for this one sample this week. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 80 percent, with fruit color improving to 94 percent this week. The pressure is firm at 19.4 pounds and starch index at 3.1.

Winesap was sampled for the second time this season. Winesap is still immature and not ready for harvest. It may be a week or so before it is ready to harvest. The percentage of fruit with internal ethylene levels greater than 0.2 ppm is up to 40 percent, with fruit color improving to 95 percent. The pressure is firm at 18.7 pounds and starch index only at 1.3.

Enterprise was sampled for the second 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 or in the same harvest window as Braeburn. Enterprise is still immature, but is quickly moving toward maturity. I think it will be ready to harvest late this week or over the weekend.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm is still low with 0 percent, with fruit color at 84 percent. The pressure is firm at 19.6 pounds and starch index has moved from 1.2 last week to 3.2 this week.

Braeburn was sampled for the second time this season. The predicted harvest date of Braeburn is Oct. 23. Some Braeburn blocks are ready now and a few blocks need just a few more days for them to mature before being harvested. So, Braeburn is maturing slightly ahead of our predicted harvest date of Oct. 23.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 55 percent, with fruit color improving from 59 percent last week to 74 percent this week. The pressure is firm at 20.1 pounds and the average starch index is 4.0, up from 2.3 last week.

Autumn Gala was sampled for the first time this season; it, too, is a variety that is not widely planted in east Michigan and one that I have not tested in previous seasons. I have read and heard from growers that it matures about five weeks behind Gala, but from this data it may be more like six weeks behind Gala. Based on this one week’s worth of data, it is ready now for harvest.

The percentage of fruit with internal ethylene levels greater than 0.2 ppm is 100 percent, with fruit color at 85 percent. The pressure is very firm at 21 pounds with a widespread of firmness, from a low of 14.6 pounds to a very firm, rock-hard firmness of 30 pounds. The starch index averaged 4.5. Again, it appears to be ready to harvest at this time. It was eating very well on Monday, Oct. 17.

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.