General apple harvest comments

The list of apple varieties ready to harvest is fairly long this week, and the order of harvest is still a bit of a moving target this season. The typical order of varieties ready to harvest is much different than in most seasons.

The maturity of apple varieties this harvest season continues to fall into two distinct categories: those that are maturing quickly and are ready to harvest ahead of schedule and those that are slowly and steadily moving toward maturity. The list of varieties being harvested at this time that fall into the “quick to mature or maturing early” includes Northern Spy, Rome, Cameo, Fuji and EverCrisp. Most varieties are falling onto this list this season. The list of those “slow and steady” maturing varieties that are being harvested at this time include Red Delicious, Idared and Crispin.

This week, growers are harvesting Red Delicious, Idared, Northern Spy, Crispin and Fiji. Varieties that are ready or nearing being ready to harvest are Rome, Cameo and EverCrisp. Varieties that were tested this week and need more time to mature include Autumn Gala, Braeburn and Winesap. More details on the maturity of each of these varieties follows.

This was the seventh week of our harvest season to collect apple samples on Monday from a number of orchards in east Michigan and have them analyzed Tuesday at the Department of Horticulture Post Harvest Lab at Michigan State University. I then tabulated the data Tuesday evening and early Wednesday morning to produce this report.

With good weather over this last weekend, growers involved in farm or direct marketing finally had a good weekend. Many growers report record sales for the weekend.

Brown marmorated stink bug (BMSB) continue to fly in high numbers on warm afternoons. Trap catches at MSU monitored trapping locations are now catching close to 60 BMSB at three quarters of the orchards in east Michigan. More sooty blotch and flyspeck, woolly apple aphid and San Jose scale is being found at many farms. A number of blocks are also seeing lenticel rot and black rot symptoms.

Here is the link for the 2018 Predicted Harvest Dates article that was posted to our MSU Extension News website  in July. A list of predicated harvest dates for east Michigan is listed at the end of this article as well. I encourage apple growers to spend time in your orchard every few days to evaluate the maturity of your apple varieties.

Individual variety results

Red Delicious was sampled for the fifth week of the season, with the mix of strains tested this week changing as many early and mid-season maturing stains have been harvested. I was still able to get a good number of Red Delicious samples this week. Three weeks ago, some early maturing Red Delicious strains and sites were ready to begin harvest, and over the last two weeks most other strains have reached maturity. This week’s data indicates that the later maturing strains are now ready to begin harvest, and some blocks are now over-mature. The predicted harvest date for Red Delicious was Sept. 29, so they are maturing after this date.

The fruit color remains good at 91 percent, the average fruit firmness dropped to 14.7 pounds and starch index moved from an average of 3.4 last week to an average of 4.1 this week. Many blocks of Red Delicious have been harvested.

Idared was sampled for the fourth week of the harvest season. Based on this week’s data, Idared are finally ready to begin harvest. Idared was very slow to mature this season. The predicted harvest date for Idared was Oct. 4, so they were not ready for harvest by this date. The fruit color is still good this week averaging 83 percent, fruit firmness dropped to an average of 13.7 pounds and the starch index has moved from 3.0 last week to 3.9 this week.

Northern Spy was sampled for the fourth week of the season, with a limited number of samples tested this week as most blocks have been harvested. Based on this week’s data, many blocks are mature to over-mature. The predicted harvest date for Northern Spy was Oct. 3, so they matured close to or just a few days after this predicted harvest date. The fruit color has washed out even more this week to 67 percent, with the starch index averaging 4.0.

Crispin or Mutsu was sampled for the fifth week of the season. Based on this week’s data, a few blocks were ready to begin harvest last week and this week most Crispin blocks are ready to harvest. The predicted harvest date for Crispin was Oct. 6, so they matured just a few days beyond this date. The fruit color has averaged 16 percent for the last three weeks, the fruit firmness has dropped from 17.3 pounds last week to 15.6 pounds this week and the average starch index moving from 3.3 last week to 4.4 this week. However, the range of starch index is quite broad, ranging from an average of 2.6 to 6.1. So, a few blocks may be over-mature. The fruit finish is excellent this season. Most blocks are eating well.

Rome was sampled for the second week of the season. Based on this week’s data, many Rome blocks were ready to harvest last week and this week many blocks are over-mature. The predicted harvest date for Rome was Oct. 7, and it appears it was ready to harvest very close to that date. The fruit color is averaging 86 percent, fruit firmness is still good averaging 17.6 pounds and the starch index moved from 5.6 last week to 6.4 this week.

Cameo was sampled for the second week of the season. Based on this week’s data, Cameo are ready to harvest. Cameo is a variety that can hang on the tree longer and still be in good shape. I didn’t have a predicted harvest date for Cameo on the chart that follows toward the end of today’s report, but I would place it just after the Fuji harvest window, or Oct. 18. Based on this week’s data, Cameo was ready to harvest a few days ahead of this date. The fruit color is averaging 71 percent this week, fruit firmness dropped from an average of 17.6 pounds last week to 16.4 pounds this week and the starch index jumped from 3.7 last week to 5.5 this week.

Fuji was sampled for the third week of the season. Last week many Fuji blocks were ready to harvest, and data from this week indicates many Fuji blocks are over-mature. The predicted harvest date for Fuji is Oct. 18, and it appears from this week’s data it was ready to harvest earlier than this date. The fruit color is good for Fuji averaging 68 percent, fruit firmness dropped this week an average of 2 pounds to 16.8 pounds and the starch index averaged 5.3.

EverCrisp was sampled for the second week of the season, with a limited number of blocks tested. Based on this week’s data and the limited sample size, EverCrisp are ready to harvest. The predicted harvest date for EverCrisp is today, or Oct. 17, and it appears from this week’s data that it is ready to harvest close to this date. Fruit color has dropped back to an average of 71 percent this week, fruit firmness averaged 19.9 pounds and the starch index averaged 4.5, with a wide range of 2.0 to 8.0. So, some fruit on the tree may be over-mature and other fruit are under mature.

Autumn Gala was sampled for the second week of the season. Based on this week’s data, Autumn Gala are still not ready to begin harvest. The predicted harvest date for Autumn Gala is Oct. 14, and it appears from this week’s data that it was not be ready by this date. The fruit color is averaging 56 percent this week, fruit firmness averaged a firm 20.6 pounds and the starch index averaged 2.8.

Braeburn was sampled for the second week of the season. Based on this week’s data, Braeburn are still not ready to begin harvest. The predicted harvest date for Braeburn is Oct. 21, and it appears from this week’s data that it may be ready to harvest close to that date. The fruit color averaged 63 percent, fruit firmness averaged 19.3 pounds and the starch index averaged 2.4.

Winesap was sampled for the first week of the season to get an early read on its maturity. Based on only one week of data, Winesap are not ready to begin harvest. The predicted harvest date for Winesap is Oct. 26, and it appears from this week’s data that it may be ready to harvest close to that date. The fruit color averaged 86 percent, fruit firmness averaged 16.5 pounds and the starch index averaged 1.7.

Predicted peak fresh market apple harvest dates for East Michigan

Each year we publish predicted harvest dates for three varieties for many locations across the state. This year's “Predicted 2018 apple harvest dates” were published July 10. These predicted harvest dates are based on a long-established formula using the bloom date and temperatures for 30 days post-bloom. The information in this article lists the bloom and harvest dates for Deerfield and Romeo, Michigan.

The following table has predicted apple harvest dates for east Michigan. It has been expanded to include more apple varieties and lists only one date for the entire east Michigan region, which is hard to do! You can adjust these predicted harvest dates based on your actual bloom dates or on the typical harvest dates at your farm.

These dates are an estimate and will be affected by the apple strain, rootstock, crop load, fertility, soil type, and other factors including weather this season. Due to the early start to our growing season and much above normal temperatures this summer, 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.

*Firmness is measured with a mechanical 11-millimeter wide probe inserted into the pared flesh of a fruit to a distance of 8 millimeters. Starch index is measured on equatorial cross section of an apple stained with iodine solution and rated using the Cornell University starch-iodine index chart for apples on a 1-8 scale (Predicting Harvest Date Window for Apples by Blanpied and Silsbey, Cornell Extension Bulletin 221.)

Looking for more? View Michigan State University Extension’s Apple Maturity page for regional reports throughout the state and additional resources.