MSU Extension

General apple harvest comments

Favorable weather over the last week has helped apple growers maintain the rapid pace of harvest. Harvest of Retain-treated Gala is taking place and the last few later maturing strains of Gala have been wrapped up. Growers are doing the final picking of Honeycrisp, with color of this “inside” fruit greatly improved in the last week. Early Fuji and Redcort have been harvested and growers are harvesting Jonathon and Cortland. Jonagold and Golden Delicious are very close to being mature for long term and CA storage. Empire maturity seems to have stalled for the past two weeks, and is not mature at this time. Red Delicious, Idared and Northern Spy were all sampled for the first time this week, with all three being immature. Black rot infected fruit are being found more commonly in the last week. Harvest labor shortages have become more acute for most apple growers in the past week as harvest is in full swing.

Table 1. Apple Maturity in East Michigan for apples harvested on Sept. 23

Individual variety results

Empire was sampled for the third week of this season. They are very slow to mature this season. Internal ethylene levels tested just at 10 percent of the fruit greater than 0.2 parts per million (ppm). Fruit have sized well in the past week. Color has improved again this week to 85 percent and fruit are firm at 17.0 lbs. I was surprised to see the starch removal index maintaining for two weeks in a row at 2.3. The brix has improved by almost 1 percent to 11.3 percent. Empire is still eating green and is not ready to harvest. Jonathan, Jonagold and Golden Delicious are actually maturing more quickly than Empire this season, thus the typical order of ripening is being reshuffled this season.

Jonathan was sampled for the second week of the season and are either mature or over mature at most farms. There is a good amount (80 percent) of internal ethylene greater than 0.2 ppm detected, color is good at 87 percent and fruit are firm at 17.0 lbs. The starch removal index has jumped from 4.2 last week to 6.8 this week. They are eating very well at this time. The predicted harvest date for Jonathan is Sept. 26 for Deerfield and Oct. 2 for Romeo, so we are picking this variety well ahead of our predicted dates.

Jonagold were sampled for the second week of the season. Like Jonathan they are showing high percentage of internal ethylene levels, now at 90 percent greater than 0.2 ppm. Fruit color has improved to 78 percent with fruit firmness the same as last week at 17.6 lbs. The starch removal index has moved from 2.9 last week to 3.9 this week. Jonagold are ready to harvest for long term and CA storage and some blocks for immediate sales.

Golden Delicious was sampled for the second week of the season, with Smoothee being the strain tested. They continue to have no fruit tested with internal ethylene levels greater than 0.2 ppm. Color or blush remains the same at 11 percent, pressure has dropped from 17.8 lbs. last week to 15.4 lbs. this week, the starch removal index tested to be the same as last week, at 4.2 and the brix improved a bit this week to 12.4 percent. Depending on the crop load, site and Golden strain, there are some blocks that are ready now for long term and CA harvest, however for immediate sales they are still eating just a bit green. Keep a close eye on the maturity of your Golden blocks.

Red Delicious was sampled for the first time of the season, and is quite a ways behind Goldens this season. All strains tested are Redchief. They are starting to show some fruit (10 percent) above the 0.2 ppm level of internal ethylene, color is excellent at 95 percent, pressure is good at 16.3 lbs., the starch is 1.7, and brix a very low at 9.7 percent. Red Delicious is very immature at this time. The predicted harvest date for Red Delicious is Oct. 4 for Deerfield and Oct. 8 for Romeo.

Idared was sampled for the first time of the season, and are testing immature at this time. They are showing that 35 percent of tested fruit are above the 0.2 ppm level of internal ethylene, color is okay at 69 percent, pressure is good at 16.2 lbs., the starch is 1.2, and brix at 10.7 percent. Idared are still eating green and are very immature at this time.

Northern Spy was sampled for the first time of the season, and is testing immature at this time. They are showing that 90 percent of tested fruit to be above the 0.2 ppm level of internal ethylene, which is typical for Northern Spy. Color is OK at 64 percent, pressure is very good at 20.2 lbs., the starch removal index is 1.9, and brix at 11.1 percent. Spys are still eating green and are very immature at this time.

Table 2. Predicted harvest dates for East Michigan

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.

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