West central Michigan apple maturity report – September 2, 2015

Phil Schwallier<schwalli@msu.edu>, Amy Irish-Brown, Denise Ruwersma and Andrea Ruwersma, Michigan State University Extension - September 02, 2015

In the Grand Rapids area, apple maturity seems to be running just about right in line with our predicted harvest dates.

General comments

Paula Red and Gingergold harvest is nearly completed on the Ridge with good quality and picking out a bit longer than expected has been reported. Fruit color and size have been outstanding so far this season. The wetter conditions in some areas have resulted in some slight fruit finish issues for some varieties and sites. Gala will be the next major variety for harvest for long-term CA storage in the Grand Rapids, Michigan area with Fulford Gala beginning any day. Macs and Honeycrisp are seven to 14 days away from major harvest. For the Hart/Shelby 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.

Water core

We are seeing 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.

Gala

Color is good to very good on most Gala strains this year, and size is good to excellent depending on fruit set. Gala have moved towards maturity from early sampling last week 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 might bit on the early side for most sites and strains with no harvest management treatments (ReTain, Harvista, etc). Some earlier strains of Gala (Fulford) should be at the stage for long-term CA storage very soon, with the majority of strains in that window early next week. Blondee maturity is similar to Buckeye Gala and both are expected to be at optimum long-term CA condition by the middle next week. We normally like to recommend a starch index of 3 for long-term storage of Gala, but if color and size are where you need them, you could pick for long-term CA storage at a starch index of 2.

Gala 2015 maturity sampling records
Date of Sample	Avg. Ethylene (ppm)	% Fruits with Ethylene over 0.2 ppm	Color % (range)	Background color (range)	Firmness lbs pressure (range)	Starch (range)	Brix range)
Aug 24	0.0694	5	80 (50-95)	2.25 (1-5)	10.2 (8.6-12)	2.75 (1-7)	10.3 (9-11)
Aug 31	0.26	30	91 (70-100)	1 (1-2)	16.7 (12.5-18.5)	2 (1-4)	10 (9-11)

McIntosh

McIntosh are not quite there yet in the general Grand Rapids area and they eat very starchy. Ethylene is low with no fruits yet being over 0.2 ppm. Pressure readings are indicating poor firmness at an average of 13.7 pounds in this week’s samples. Color is excellent, of course, on Ruby Mac and very good in other Mac strains and improving every day. Brix reading is rather poor at 10.9, but is expected to improve in the next 10 days. Harvest for long-term storage of Macs can begin at any time color is right, with the majority of harvest coming in 10 to 14 days. Our predicted harvest date for Macs is Sept. 11. Be watchful in blocks with a heavy fruits set as drop could occur from fruits pushing themselves off.

McIntosh 2015 maturity sampling records
Date of Sample	Avg. Ethylene (ppm)	% Fruits with Ethylene over 0.2 ppm	Color % (range)	Background color (range)	Firmness lbs pressure (range)	Starch (range)	Brix (range)
Aug 24	0	0	78 (60-95)	2.9 (1-5)	8.4 (7.2-11)	2.4 (1-4)	11.5 (10-13)
Aug 31	0.0084	0	90 (70-98)	1.5 (1-3)	13.7 (11.5-15.5)	3.4 (3-4)	10.9 (10.5-11)

Honeycrisp

Moving toward maturity, but still immature overall. There are a few fruits, or “shiners,” that are near ready, but the majority of Honeycrisp are not physiologically ready for harvest in the Grand Rapids area. Being economically ready is a different story, with a bitter ending if done too soon – you can kill return sales by picking subpar Honeycrisp too soon. Firmness readings are varied from very poor at around 10 pounds to excellent at 17.7 pounds pressure. Starch readings are very low with solid readings of 1 across many samples which indicates immaturity. Brix level is good, but not yet excellent at 11.7. Our predicted harvest date of Sept. 14 seems accurate for a first pick of Honeycrisp around the Ridge.

Honeycrisp 2015 maturity sampling records
Date of Sample	Avg. Ethylene (ppm)	% Fruits with Ethylene over 0.2 ppm	Color % (range)	Background color (range)	Firmness lbs pressure (range)	Starch (range)	Brix (range)
Aug 24	0.0472	0	30 (5 - 80)	4.4 (2-5)	9.7 (8.2-12.3)	1 (1-1)	11.1 (10.2-12)
Aug 31	0.1425	20	67 (40-80)	1.5 (1-3)	17.7 (15.5-22.5)	1 (1-1)	11.7 (11-12)

Normal and 2015 peak harvest dates for varieties for the Grand Rapids area
Variety	Normal date	2015 predicted date
Paulared	8/24/15	8/20/15
Gingergold	8/26/15	8/22/15
Gala	9/10/15	9/6/15
McIntosh	9/15/15	9/11/15
Honeycrisp	9/18/15	9/14/15
Empire	9/22/15	9/18/15
Jonathan	9/28/15	9/29/15
Jonagold	9/28/15	9/29/15
Golden Delicious	10/2/15	10/3/15
Red Delicious	10/5/15	10/5/15
Idared	10/10/15	10/10/15
Rome	10/15/15	10/15/15
Fuji	10/25/15	10/25/15
Braeburn	10/25/15	10/25/15
Goldrush	11/1/15	11/1/15

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

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).