MSU Extension

General comments

In the Grand Rapids, Michigan, area, early harvested apple maturity seems to be running in line with or even slightly ahead of our predicted harvest dates. Fruit size has been excellent so far this season. Fruit color is fair to good, and could be better – maybe some cooler weather will help with color. The wetter conditions in some areas have resulted in some slight fruit finish issues for some varieties and sites. Gala are just beginning to be harvested for long-term controlled atmosphere (CA) storage in the Grand Rapids area. Honeycrisp harvest is just beginning where color is good, with the major harvest probably a week way. For the Hart/Shelby, Michigan, area, growers can expect harvest dates for that area to be behind the Grand Rapids area using this guide: along the lakeshore approximately six days behind Grand Rapids; areas inland about four days behind.

We continue to see a higher incidence of water core in early harvested apples so far this season. Given the high amounts of rain that some areas have received in the last four weeks, you should be paying close attention to water core in varieties that are highly susceptible to it this season and harvest accordingly. Special preconditioning treatment prior to storage may be warranted for some lots of fruit with high water core potential.

Hopefully early harvested varieties are not an indication of things to come, but we are seeing higher levels of bruising in some lots than usual. It could be due to the higher amount of rainfall we’ve had recently. Even the most carefully picked fruit might show bruising from just bumping other fruits in the picking bag.

Very high levels of bitter pit are being noticed in Honeycrisp in particular. There doesn’t seem to be a correlation with cropload as is commonly the issue. Again, this is most likely due to the extremes in rainfall as it does seem to be less prominent in irrigated blocks.

Individual variety results

Color is good to very good on most Gala strains this year, and size is good to excellent depending on fruit set. Gala took a major jump forward in maturity this week compared to last and growers should watch their individual blocks very carefully. Our predicted harvest date for Gala for long term CA storage is Sept. 6 and that was adequate for earliest sites for long-term CA storage harvest. Michigan State University Extension normally likes to recommend a starch index of 3 for long-term storage of Gala, and our samples indicate fruits are there. Gala seem to be moving quickly, most likely due to warmer weather. We are also noticing a slightly lesser affect from ReTain applications in Gala samples this year, so be sure to do spot checks of your fruit and not assume you will get the full five to seven days from your ReTain applications.

McIntosh are very close to where we need them for long-term CA storage. Harvest should begin for long-term storage as color is good. Ruby Macs are being harvested this week on the Ridge. Ethylene is lower than expected for McIntosh, but they are changing with 87 percent of fruits sampled being just over the climacteric of 0.2 ppm. Pressure readings are very good for McIntosh. Color is excellent of course on Ruby Mac and good to very good in other McIntosh strains and improving every day. Brix reading improved from 10 last week to 11.8 this week. Harvest for long-term storage of McIntosh can begin at any time color is right. Our predicted harvest date for McIntosh is Sept. 11, which should be correct for the majority of the Ridge crop. Be watchful in blocks with a heavy fruit set as drop could occur from fruits pushing themselves off.

Honeycrisp sampled made a definite move forward in maturity and some harvest has begun for the reddest fruits. Our predicted harvest date of Sept. 14 seems accurate for a first pick of the bulk of Honeycrisp around the Ridge. Firmness readings are varied, but still very good at 17 pounds pressure. Starch readings are still very low at an average of 1.9, but they are changing overall from last week. Brix level is good, but not yet excellent at 11.4. Getting color has been a bit of a struggle this season for Honeycrisp. Bitter pit is a major problem this season in Honeycrisp with some blocks having as much as 30 percent fruits with bitter pit already. Ideally, you want to harvest your Honeycrisp as soon as you can get the red color, but before the bitter pit shows.

This is our first week of sampling Empire on the Ridge. All maturity indices indicate immaturity. Our predicted harvest date for Empire is Sept. 18, which looks to be a good target.

This is our first week of sampling Jonagold on the Ridge. Our predicted harvest date for Empire is Sept. 29, and it’s a bit too early to tell if this date will be a good target. Another week of sampling will show the way. All maturity numbers indicate immaturity.

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.

Additional resources

• Watercore in apples: Causes, concerns, detection and sorting
• Tools to help manage apple harvest
• Why does apple fruit drop prematurely?
• Use summer NAA to enhance return bloom on apple varieties
• Starch chart for Honeycrisp apple fruit
• Lenticel infections and bitter rot of apples
• Checking apple maturity: What to look for
• Predicting harvest date windows for apples