MSU Extension Apples

General harvest comments

Harvest of prominent commercial varieties is finally underway on most apple farms in west central Michigan. McIntosh, Early Fuji, Jonathan, first color picks of Honeycrisp and early Gala orchards are being harvested this week. The beginning of next week will mark the start of large-scale Gala and Honeycrisp harvest throughout the region.

Normally, the first half of September would have already seen the harvest of McIntosh, Gala and other earlier fresh market varieties, but a later growing season slowed the maturity of these earlier varieties. Gala is particularly slow this year, and has fallen behind Honeycrisp in harvest order based on maturity on many area farms. If you have a light crop of Honeycrisp in a mature orchard or a young planting with a small crop, make sure you are monitoring maturity in those fruits carefully because they seem to be moving very fast. Many growers figure that since they have not yet picked Gala, they have plenty of time on the Honeycrisp, but data this week indicate that while Gala is slow this season and should wait until the beginning of next week, Honeycrisp is very close or already testing in the mature range at many sites.

Although earlier varieties like Gala, Early Fuji and McIntosh are behind a week or two, varieties that mature in the second half of September or later in a typical year are running right on track with typical maturity windows. This means that Honeycrisp, Empire, Jonagold and other varieties slotted for this window will still need to be harvested at a fairly typical time as growers rush to get through the earlier varieties they have been waiting for. The compression on maturity windows is going to mean some scrambling from growers through the rest of September.

In general, fruit quality looks outstanding this season. Size is good on most farms and color is beautiful. Fruit running through the lab are firm and have good sugar levels, the heat this week and significant rainfall last week does not appear to be causing any soft fruit yet. Although the compression in harvest windows for several varieties means more stress for growers, the upside is that the fruit that is coming out of orchards looks excellent.

If you are feeling stressed about getting through prominent varieties before things move into over-maturity remember ReTain at reduced rates combined with NAA can delay harvest by several days and reduce fruit drop. One-quarter pouch of ReTain plus 10ppm NAA is a common rate used for this purpose on Honeycrisp and Gala at this time of year.

Since the effect of ReTain is rate dependent, variable rates can be used within a single block to stagger the harvest of a variety, allowing you to prolong the acceptable range while your pickers move through. It can also be used after a first pick for color to stick the second pick on the tree for a few days. This practice is becoming particularly popular with Honeycrisp, as a low rate can be used immediately after a first color pick to stick the remainder of the fruit on the tree a few more days to wait for better color.

Brown marmorated stink bug pressure continues to be low so far this season in west central Michigan, but a significant uptick has been reported in other areas of the state. The majority of our orchards are already boxed and no insecticides will be applied at this point in most cases, but we will continue to monitor the brown marmorated stink bug situation until harvest has concluded.

Individual variety maturity results

The scales used to rate these different metrics on these charts are as follows:

• Background color: scale 1-4, 1 is fully yellow and 4 is fully green.
• Russet: 1-4, 1 is no russet and 4 is severe russet.
• Pressure: always listed in pounds, and two pressure scores are recorded for each apple tested.
• Watercore: 0-4, 1 is no watercore and 4 is severe watercore.
• Bleeding: 0-4, 0 is no bleeding of red color into flesh and 4 is severe bleeding of red color in to flesh.
• Red: listed as a percentage of the whole fruit with red color.

McIntosh

This variety is ready to go throughout the region and continues to run ahead of Gala this year. Our sample sites reduced this week because picking was already underway at a couple of our typical sampling locations. McIntosh is considered ready for controlled atmosphere (CA) storage at a starch index of 5 with suggested firmness between 14 and 16 pounds. Samples collected Monday tested either at or just shy of the suggested starch index, and firmness is starting to drop below the recommended range.

Macs should be prioritized this week, particularly for anyone trying to figure out whether they should go after Macs vs. Gala, Honeycrisp, Early Fuji, etc.

Early Fuji

Early Fuji are just entering their maturity window and most sites can be harvested whenever you get to them. Sites in Oceana County are generally ready; sites in Mason County tested on the early side of maturity or just shy of this mark in the first half of this week. The second half of this week and early next week is an ideal time to go after this variety for growers who have it, particularly for anyone who is waiting on Gala to move along. It was generally more ready for harvest this week than Gala.

Very little watercore has been observed on this variety so far this season. Early Fuji is not known for having noteworthy color, but fruits this year look pretty good thanks to some very good weather for red color development over the past three weeks.

Gala

It’s a slow year for this variety, and quite a bit of ReTain plus NAA was used on Gala this year in the area which further skews this result. Color has been so good that some growers have been itching to pick these for over a week, but focus your attention on McIntosh, Early Fuji, Jonathan and early picks of Honeycrisp in the second half of this week. Results suggest that even earlier sites in Oceana County should wait to get into Gala until the beginning of next week. Some later sites closer to the lake in Oceana County and many sites in Mason County may need closer to seven to 10 days to reach the optimal window for harvest for CA storage.

Gala are considered mature for CA storage at a starch index of 3 with suggested firmness between 16 and 18 pounds. Fruits are shy of the suggested starch index mark and are testing consistently between 18 and 22 pounds, so anyone concerned about fruit softening in the heat doesn’t have much to worry about if you wait until next week for harvest.

Jonathan

This variety was sampled for the second time this week and was either ready or just shy of ready for CA storage as of Monday’s sample collection. It can be picked for CA storage in the second half of this week and into next week; it is very likely in the early range of the optimal harvest window throughout the region now.

Jonathan have been quite small this year at both sites we have been tracking, and quite a bit of russet was recorded as well. Color is good, and no bleeding of color into flesh has been observed. If you have it, this is another good variety to send pickers in to this week if you need to keep folks busy while you wait the weekend out for Gala to be ready.

Honeycrisp

This variety moved forward very quickly in a week’s time and is ready for harvest at some sites. The decision on whether to get into first picks of this variety this week is extremely dependent on location in the region and size of the crop. Generally, young trees carrying a first/second crop or mature orchards with a light crop are ready for a first pick, but later sites in Oceana County and many sites in Mason County with a large crop could stand to wait until late next week for a first pick.

Pay attention to any young plantings you are cropping for the first or second time this year—these blocks are moving a lot faster than many growers expected. Several growers who called in this week had not considered getting in these blocks because they were still waiting on Gala harvest, but fruits tested from these blocks were far ahead of Gala, so there are going to be quite a few situations this year where it is better to get after Honeycrisp before getting in to Gala. If tree age and crop load is the same, this is likely not the case, but remember there is a lot of young Honeycrisp acreage in our area right now. A first crop on a third leaf Honeycrisp can ripen faster than a full crop on a mature Gala in a year like this.

We also know from experience that light crops tend to mature rapidly on a tree of any age, and Honeycrisp is light in many area orchards this year. Make sure you are either checking fruits from these blocks on your own or dropping off samples at the lab in the second half of the week as you weigh your options.

Empire

This variety will likely start to test on the early end of the mature range for CA storage this time next week. Growers have many other priorities in the next 10 days, so the earliest picks of this variety are likely well over a week away. Size on Empire is small this year, so continue to hope that the variety picks up some size in the next couple of weeks. Empire is considered mature for CA storage at a starch index of 3.5 and suggested firmness of 14-16 pounds.

Jonagold

Early maturity for CA storage is likely about 10-14 days out for this variety, depending on site. Earlier sites in Oceana County could test in the mature range by the end of next week, while most locations in Mason County and later sites in Oceana County are likely several days behind that mark.

Jonagold is considered mature for CA storage at a starch index of 3.5 with suggested firmness of 15-17 pounds. This variety is not far behind the typical maturity range we would expect in a normal year, so do not expect that the same delay that has applied to Gala and McIntosh will continue with later varieties. They aren’t much behind normal dates. Color and size are both excellent on Jonagold this season.

*Firmness is measured with a mechanical 11-mm wide probe inserted into the pared flesh of a fruit to a distance of 8 mm. 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.)