MSU Extension

General apple harvest comments

Apple harvest is almost at full throttle at most farms. This week I repeated apple maturity testing on the six varieties tested last week, and I added five new varieties that are approaching maturity. Growers are picking McIntosh and working away at Gala as the different strains begin to eat better. Gala are very slow to ripen this season and have generally not eaten well. Early maturing Gala strains that were treated with Retain are being harvested as well. Light pickings of Honeycrisp are taking place for the most mature fruit. Early Fuji and Jonamac are being harvested as well. It appears that Jonagold are maturing very quickly, as is Empire. Both are at least a week to 10 days from beginning of harvest.

With abundant soil moisture supplies this season at most fruit farms, fruit size is generally excellent this season, with growers noticing a marking increase in size in the last week. Fruit color has improved in the last week. Internal ethylene levels are low in most varieties so far this season, with the exception of Gala, Honeycrisp and Jonamac. I am noting that the brix or sugar levels have been lower this season compared to average, most likely related to more water being in the fruit due to abundant soil moisture supplies this season for most growers. Harvest labor remains in short supply for most apple growers.

Apple maturity in southeast Michigan for apples harvested Sept. 15, 2014

Individual variety results

Gala were sampled for the third week of the fall harvest season. Growers are harvesting Gala strains as they mature, but overall they are slow to mature and are still not eating well, so growers have moved on to McIntosh and Honeycrisp to allow Gala more time to ripen fully. Color in many blocks is also lacking, averaging 70 for the last three weeks. Gala fruit size is excellent this season. The fruit remains firm averaging 17.4 pounds, and the starch index has moved from 2.4 to 3.7 this week. One caveat to add is that some Gala blocks have a great deal of variability of starch readings, ranging from 1 to 8 in the same block.

McIntosh was sampled for the third week of the season and have moved along quickly toward maturity. Most blocks had low percentages of fruit with internal ethylene levels greater than 0.2 parts per million (ppm), averaging 7. The color has generally improved in McIntosh over the last week; it was averaging 63 last week, improving to 78 this week. The firmness dropped 0.5 pounds in the past week to 14.1 pounds. The starch removal moved from 4.0 last week to 5.4 this week; recall that McIntosh need to be closer to 5 to be considered mature, higher than any other variety. While they are eating much better this week, the brix is unchanged at 11.1. McIntosh are “picking easy” this week, so growers need to get them harvested soon.

Honeycrisp were sampled for the third week of the season. Honeycrisp always have a wide range of fruit maturity, and this season it is typical; most seasons they require three to four pickings. The background color is finally breaking in most blocks and the fruit on the outside of the tree is coloring well. They eat much better than last week. Much of the fruit on the inside of the tree is still very green. Fruit with internal ethylene levels greater than 0.2 ppm are up to 90 this week, last week 75 of the fruit were at this level. The color of the most mature fruit sampled from the outside of the tree is up to 66 with firmness down only slightly to 15.0 pounds. The starch removal averaged 2.8 last week and jumped to 4.9 this week. The brix improved to 12.4 this week. Honeycrisp harvest started late last week at most farms, and at some farms growers are considering doing a good second picking in the next few days.

Early Fiji was sampled for the second week of the season and both blocks tested were a bit over mature. Internal ethylene levels in fruit greater than 0.2 ppm rose slightly to 20 this week. Fruit color is good, averaging 67, and pressure is averaging 15.0 pounds. The starch removal averaged 6.8 this week, up 2 full points from 4.8 last week. The brix was unchanged at 10.6.

Empire was sampled for the second week of the season and appears to be over a week away from being ready to begin harvest, even for controlled atmosphere (CA) and long-term storage. Most blocks had low percentages of fruit with internal ethylene levels greater than 0.2 ppm, averaging 3. Fruit color is good, averaging 70 and pressure is averaging 13.0 pounds, dropping from 14.7 pounds last week. The starch removal averaged 2.1 with a brix at 10.4.

Cortland was sampled for the second week of the season and is a long way from being ready to begin harvest. None of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is good, averaging 70 and pressure is averaging 14.6 pounds, down from 16.1 pounds last week. The starch removal averaged a low 1.0 with a brix of 10.5.

Jonamac was sampled for the first week of the season and appears to be ready for harvest, although I had just one block tested. All 100 of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is good, averaging 89 and pressure is averaging 14.6 pounds. The starch removal averaged 4.5 with a brix of 10.9.

Jonathan was sampled for the first week of the season and appears to be a long way off at this time. None of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is excellent, averaging 87, and pressure is excellent, averaging 18.9 pounds. The starch removal averaged 2.3, with a brix very low at 11.6.

Jonagold was sampled for the first week of the season and appears to be closer to harvest than I expected. Just 30 of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is good, averaging 54 and pressure is averaging 15.7 pounds. The starch removal averaged 4.4, with a brix 11.3. I plan to do more samples next week and will have more news on Jonagold then.

Golden Delicious was sampled for the first week of the season and appears to be a long way off at this time. Just 10 of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is poor to fair, averaging 6 and pressure is averaging 16.2 pounds. The starch removal averaged 1.3 with a brix at 11.6.

Northern Spy was sampled for the first week of the season and appears to be a very long way off at this time. None of the fruit sampled are producing internal ethylene levels greater than 0.2 ppm. Fruit color is average at 33 and pressure is averaging 21.4 pounds. The starch removal averaged 1.1 with a brix very low at 9.8.

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.