MSU Extension

General apple harvest comments

Apple harvest continues to move forward at full speed this week. Note that apple varieties are not maturing in the typical order this season. Growers are harvesting Golden Delicious and Fuji with Northern Spy being harvested at many farms. In the southern parts of our region, early maturing strains of Red Delicious are starting to be harvested. Many varieties are slow to mature this season, most notably Red Delicious and Ida Red. Many Fuji blocks are much more mature than I expected.

Most apple varieties are picking hard this season with the exception of Red Delicious. There has been little to no pre-harvest drop or picking loss. With abundant soil moisture supplies at most farms, fruit size has been generally good to excellent. Fruit color has continued to improve again this past week. Internal ethylene levels are finally coming up to their normal levels in the past two weeks as are brix or sugar levels. Bitter pit is being seen in some Ida Red and Northern Spy blocks.

This week I repeated apple maturity testing on the seven varieties tested last week and added one new variety, Winesap. 

Apple maturity in southeast Michigan for apples harvested Oct. 6, 2014

Individual variety results

Golden Delicious (Smoothee strain) was sampled for the fourth week of the season. Its maturity has moved along quickly in the last week; most growers in the southern region have finished picking them and in the rest of the region are being harvested this week. Fruit size is generally good and fruit finish is excellent.

Golden Delicious are eating well. Approximately 45 percent of fruit tested are producing internal ethylene levels greater than 0.2 parts per million (ppm). Fruit color or blush is poor to fair, averaging 12 percent, and pressure is still firm, averaging 16.1 pounds. The starch removal averaged 5.2, up sharply from 3.1 last week, with a brix at 13.9 percent.

Red Delicious (Redchief strain) was sampled for the third week of the season and seems to be slow to mature or ripen. Early maturing strains are starting to harvest, but most strains are still not ready to begin harvest. There is quite a gap in maturity between Golden Delicious and Red Delicious this season. Almost two-thirds, or 65 percent, of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm.

Fruit color is good at 88 percent and pressure is averaging 15.8 pounds, which is surprising to see pressure so low in an apple that is not close to being physiologically mature. The background color is still green in most strains of Red Delicious. The starch removal averaged 2.8, up from 1.3 last week. The brix is almost the same as last week at 11.1 percent. Water core and moldy core are being found in 10 to 30 percent of the fruit. Lastly, Red Delicious is the only variety to pick easy this week.

Ida Red was sampled for the third week of the season and, like Red Delicious, appears to be slow to mature. This week, 85 percent of fruit tested are producing internal ethylene levels greater than 0.2 ppm. Fruit color is 64 percent and pressure is averaging 15.6 pounds. The starch removal averaged 2.1 with a brix at 12.2 percent. While Ida Reds are maturing, they are not ready for harvest.

Northern Spy was sampled for the fourth week of the season and ready for harvest at many farms, with others being four to five days from being ready. Internal ethylene levels in fruit greater than 0.2 ppm is at 92 percent. Fruit color is at 46 percent, pressure is averaging 19.2 pounds, and starch removal averaged 3.1 with many blocks being close to 4.0. The brix has climbed from 11.0 percent last week to 12.3 percent this week.

Fuji was sampled for the second week of the season and has moved along quickly in the past week. Many if not most strains are ready for harvest, and are more mature than Red Delicious, Ida Red and Northern Spy. I encourage growers to take a look at Fuji maturity quickly.

This week, 60 percent of fruit tested are producing internal ethylene levels greater than 0.2 ppm. Fruit color is average at 56 percent and pressure is averaging 16.8 pounds, down from 17.4 pounds last week. The starch removal averaged a surprising 4.6 with a brix very high at 14.1 percent.

Cameo was sampled for the second week of the season and still appears to be a long way off. This week, 40 percent of fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is average at 46 percent and pressure is averaging 19.5 pounds. The starch removal averaged 1.7 this week, up from 1.0 last week, with a brix the best of any variety tested this week at 14.2 percent.

Crispen or Mutsu was sampled for the second week of the season and also appears not to be ready for harvest. This week, 40 percent of fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color or blush is average at 11 percent and pressure is averaging 18.3 pounds. The starch removal averaged 2.9, up from 1.5 last week, with a brix of 13.2 percent. Most blocks have a good amount of blister spot developing in the last two weeks or so.

Winesap was sampled for the first week of the season and appears to be a very long way off. This week, 40 percent of fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is average at 56 percent and pressure is averaging 18.0 pounds. The starch removal averaged 1.5 with a brix of 12.0 percent.

Predicted apple harvest dates

Each year we publish a predicted harvest date for three varieties for many locations across the state. This year’s dates can be seen at “Predicted 2014 apple harvest dates,” published July 17. The table below lists the bloom and harvest dates for the Michigan cities Deerfield and Romeo. You can adjust your predicted harvest dates based on your bloom dates. The 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, and from the data I generated from this week’s samples, I believe that these harvest days are going to be fairly close to the actual dates for a variety nearing maturity.

Predicted harvest dates for southeast Michigan

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.