MSU Extension

General apple harvest comments

Harvest of Cortland and Jonathan is wrapping up and growers are starting to harvest Jonagold, Golden Delicious and Empire. The maturity of Empire is finally moving along, but note that maturity of Jonagold and many strains of Golden Delicious are ahead of Empires this year. Red Delicious, Idared and Northern Spy are all testing at about the same maturity level and are close to being mature for long-term and CA storage harvest. With the exception of Sunday, Sept. 29, 2013, the weather has been favorable for harvest.

Black rot infected fruit continues to be found more commonly in the last week. Harvest labor shortages continue for most fruit farms. Growers need to consider leaving some varieties hanging for a bit longer and move onto other varieties that are at their peak of maturity and are more valuable when harvested in prime condition. Growers can then come back to these varieties later that are intended for processing or juice.

Apple maturity in southeast Michigan for apples harvested on Sept. 30, 2013

Individual variety results

Empire was sampled for the fourth week of this season. Their maturity is moving more quickly and is finally ready to harvest for both long-term storage and fresh sales. They have been very slow to mature this season. Internal ethylene levels are still low at 20 percent of the fruit greater than 0.2 parts per million (ppm). Fruit size and color have improved. Color is 79 percent and fruit are firm at 16.4 pounds. The starch removal index jumped two full digits to 4.3; it had remained steady at 2.3 for two weeks. The brix has improved to 11.9 percent. Empire is eating much better; however, see my notes for both Jonagold and Golden Delicious as these varieties are well ahead of Empire this season. As I stated in last week’s report, the order of ripening is being reshuffled this season.

Jonagold were sampled for the third week of the season. They are testing a high percentage of internal ethylene, now at 85 percent, greater than 0.2 ppm. Fruit color has dropped a bit to 67 percent with fruit firmness the same as last week at 17.7 pounds. The starch removal index has moved from 3.9 last week to 6.1 this week. Jonagold are over-mature at some farms for long-term and CA storage and are ready to harvest for immediate sales.

Golden Delicious was sampled for the third week of the season with Smoothee being the stain tested. Fruit are just starting to produce internal ethylene with 50 percent of fruit tested with internal ethylene levels greater than 0.2 ppm. Color or blush remains about the same at 14 percent, pressure has remained about the same at 15.3 pounds this week, the starch removal index jumped from 4.2 last week to 6.1 this week and the brix improved this week to 13.6 percent. Depending on the crop load, site and Golden strain, there are some blocks that are over-mature for long-term and CA harvest and are ready now for immediate sales. Keep a close eye on the maturity of your Golden blocks.

Red Delicious was sampled for the second week of the season and remains way behind Golden Delicious this season. All strains tested are Redchief. They are showing low levels of internal ethylene at 15 percent above the 0.2 ppm level, color is excellent at 99 percent, pressure is good at 17.1 pounds, the starch is 3.0, up from 1.7 last week, and brix are very low at 9.4 percent. Red Delicious is immature at this time. The predicted harvest date for Red Delicious is Oct. 4 for Deerfield, Mich., and Oct. 8 for Romeo, Mich. I feel they will be maturing later than these dates this season.

Ida Red was sampled for the second week of the season and is testing about the same as Red Delicious this season. They are immature at this time. They are showing that 60 percent of tested fruit are above the 0.2 ppm level of internal ethylene, color is improving to 79 percent, pressure is good at 16.7 pounds, starch is up from 1.2 last week to 3.0 this week, and brix at 11.5 percent. Ida Red are still eating green and are immature at this time.

Northern Spy was sampled for the second week of the season and is testing about the same maturity as Red Delicious and Ida Red. They are immature at this time. They are testing 100 percent of fruit to be above the 0.2 ppm level of internal ethylene, which is typical for Northern Spy. Color is OK at 61 percent, pressure is very good at 19.8 pounds, the starch removal index is up from 1.9 last week to 3.0 this week, and brix up a percentage point to 12.1 percent. Spys are still eating green and again are immature at this time.

Fuji was sampled for the first time this season. The results indicate they are not ready for harvest at this time, however, and are not far behind this group of three varieties with similar maturity: Red Delicious, Ida Red and Northern Spy. The internal ethylene levels greater than 0.2 ppm tested at 65 percent with color at 75 percent, background color at 3.0, pressure testing at 19.3 pounds, the starch was a surprising 2.6 and brix also surprisingly at 13.3 percent. Let’s see what next week’s test results on Fuji reveal in terms of maturity.

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.