General apple harvest comments

The weather is certainly feeling like fall. Daytime temperatures are predicted to be in the low 60 degrees F, which is certainly cooler than the previous week. By next week, we might be back up into the 70s again. Overnight temperatures are also predicted to be cool and will dip into the 40s for the lows. There is some frost that might hit the center part of the state, but our area next to the lake will remain above freezing. These cool conditions will help color up the fruit. There is also rain in the forecast for today and into tomorrow.

Growers are anxious to get the season underway, but most varieties are still not ready to pick for fresh eating. Growers are harvesting Ginger Gold, SweeTango, and Premier Honeycrisp at this time, but most other varieties need more time to ripen. Most of the varieties we tested yesterday are still very firm and the starch removal index is still relatively low for fresh eating. Brix levels are increasing at this time, which is a good sign for good quality fruit later in the weeks to come. Fruit are firm, and color is excellent for this time of the year.

Apple maturity in northwest Michigan for apples collected on Sept. 8, 2020
Variety	Color % (range)	Firmness lbs. (range)	Starch (range)	Brix %
McIntosh	88% (60-100)	18.7 (14-23)	1.8 (1-4)	11.1 (9-12)
Ginger Gold	13%	17.4	2.3	12
SweeTango	72.4% (50-100)	17.2 (13.5-19)	2.9 (2-5)	12.4 (11-15)
Honeycrisp	51% (5-95)	18.6 (16-22)	1.2 (1-2)	10.4 (8.8-11.4)
Gala	82% (20-100)	21.3 (17 -23)	1.9 (1-7)	11.2 (9-14.6)

Ginger Gold maturity sampling for the harvest season
Sample date	Color % (range)	Firmness lbs. (range)	Starch (range)	Brix %
Sept. 1, 2020	12.5%	19.8	1.2	11.1
Sept. 8, 2020	13%	17.4	2.3	12

Ginger Gold harvest is underway, and we sampled one block of Ginger Gold this week. The apples have held firmness and are eating better this week than last. Starch indices have increased one point and Brix have increased one degree since last week.

SweeTango maturity sampling for the harvest season
Sample date	Color % (range)	Firmness lbs. (range)	Starch (range)	Brix %
Sept. 1, 2020	46.5%	17.8	1.35	12.3
Sept. 8, 2020	72.4% (50-100)	17.2 (13.5-19)	2.9 (2-5)	12.4 (11-15)

Spot picking of SweeTango is underway, and we sampled three blocks this week. The apples are ripening and there is variability within the blocks as well as among orchards. We have been picking the ripest looking fruit to sample and have been surprised by the variability in maturity parameters. Firmness is decreasing, starch indices are increasing, and we have observed good color improvements since last week. We observed a few apples with water core, but overall the apples are juicy and delicious.

McIntosh maturity sampling for the harvest season
Sample date	Color % (range)	Firmness lbs. (range)	Starch (range)	Brix %
Sept. 1, 2020	83% (60-100)	18.9 (16-22)	1.1 (1-1.5)	10.25 (9.6-11)
Sept. 8, 2020	88% (60-100)	18.7 (14-23)	1.8 (1-4)	11.1 (9-12)

McIntosh color is continuing to improve. We sampled five blocks of McIntosh this week and maturityparameters indicate that these apples are ripening. Firmness is holding, but variable; starch indices and brix are increasing. These apples still have time before they are ready to eat fresh, but they are approaching the timing to pick for storage. Flavor is excellent with some apples already tasting like the traditional bright taste of McIntosh.

Gala maturity sampling for the harvest season
Sample date	Color % (range)	Firmness lbs. (range)	Starch (range)	Brix %
Sept. 8, 2020	82% (20-100)	21.3 (17 -23)	1.9 (1-7)	11.2 (9-14.6)

This was our first week testing Gala, and we sampled six blocks. Most of the blocks that we sampled were not quite mature. However, maturity parameters of one block of Wildfire Gala indicated that this block of apples are mature with an average starch index of 5.1 and nearly 14 degrees Brix. The other five blocks that were sampled had substantially lower starch and Brix readings ranging from 1-1.8 and 9.8-11.2, respectively. Color and flavor are excellent, and several growers have been pleased with Gala size this year.

Honeycrisp maturity sampling for the harvest season
Sample date	Color % (range)	Firmness lbs. (range)	Starch (range)	Brix %
Sept. 1, 2020	41.3% (15-70)	19.2 (16-23)	1 (1-1.5)	10.0 (8.6-10.8)
Sept. 8, 2020	51% (5-95)	18.6 (16-22)	1.2 (1-2)	10.4 (8.8-11.4)

本周我们取样5密脆块,this variety is not yet ready for picking. The apples are still firm with relatively low degrees brix and percentage color at this time. Starch indices have not changed much since last week. While most blocks of Honeycrisp are not ready for harvest, growers with the earlier variety Premier Honeycrisp have started harvest; these apples can be found at markets.

Suggested firmness and starch index levels for long-term and shorter-term controlled atmosphere (CA) storage by variety.
Variety	Firmness (pounds)*			Starch Index*
	Short CA	Mid-CA	Long CA	Mature	Over mature
McIntosh	14	15	16	5	7
Gala	16	17	18	3	6
Honeycrisp	15	16	17	3.5	7
Empire	14	15	16	3.5	6
Early Fuji	16	17	18	3	7
Jonagold	15	16	17	3.5	5.5
Jonathan	14	15	16	3.5	5.5
Golden Delicious	15	16	17	3	6.5
Red Delicious	16	17	18	2.5	6
Idared	14	15	16	3.5	6
Fuji	16	17	18	3	7
Rome	15	16	18	3	5.5

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

Looking for more?ViewMichigan State University Extension’sAppleMaturitypage for regional reports throughout the state and additional resources.