West central Michigan apple maturity report – Aug. 21, 2019

Don’t let the calendar date fool you into premature harvest of early apple varieties. West central Michigan apples are several days behind normal harvest dates this year.

August 21, 2019 - Author: ,

Apple trees
Wildfire Gala (left), an early maturing strain, planted next to Brookfield Gala (right), a normal season Gala strain. Photo by David Jones, MSU Extension

General harvest comments

In a typical year, growers would be eyeing the harvest of some of our earlier apple varieties this week. We all know this is not a typical year; however, most varieties are running at least a week behind a normal growing season right now. Temperate days and cool nights in the next two weeks should provide us with excellent color, and this might tempt some to get started with harvest at the normal time, but don’t be fooled. Data collected this week indicates that harvest needs to be delayed this year.

If you have not summer pruned to open up canopies and get sunlight into ripening fruit of fresh market varieties, do so as soon as possible. The heavy rains this year have resulted in extremely thick vegetative growth, and red color will not develop properly without exposure to sunlight because biosynthesis of anthocyanin (the pigment that is responsible for red skin color in apple fruits) does not occur at desired levels without sufficient sunlight exposure. Anthocyanin biosynthesis is also inhibited by warm temperatures, which is why cool weather before harvest is always good news to the apple grower.

If you have summer prune aggressively at this time of year, be cautious of photo-oxidative sunburn, which typically occurs when fruits that were previously shaded are suddenly exposed to direct sunlight. This type of sunburn can occur even when temperatures are mild, so a cool week does not alleviate the risk of this happening, particularly on varieties that tend to be sensitive to burn. The damage manifests itself initially as a bleached look which eventually turns brown. Sunburn protection products can be used to help reduce risk, and selecting a span of a few days with partial sun or rain on the forecast for summer pruning rather than a week with intense sun can further help to reduce risk.

The timing for ReTain applications is either upon us or quickly approaching, so make sure you are coming up with a game plan on timing and rates. You can check out a few good ReTain reminders by reading Michigan State University Extension’sReTain and NAA as a standard practice for apples.”

Insect update

Insect management is entering the home stretch, but needs to be on everyone’s radar for a few more weeks due to how late the season is. Lower degree day accumulations mean that several pests are likely to start later and hang around longer than we would tend to expect. Apple maggot is active at this time and should be on everyone’s priority list right now, especially with all of the rain we have had recently. We often see new flushes of this pest emerge after a soaking rain, and we have had several in the past two weeks. Bait red sphere traps with apple volatile to improve efficacy. The threshold for these traps is five apple maggots.

Second generation codling moth is underway. Closely monitor individual orchards to determine a biofix. After a biofix is established, target an application of insecticide at about 250 growing degree days base 50 from that catch date, as this will coincide with the start of egg hatch. Be cautious in setting second generation biofix across your acreage this year for codling moth, a sporadic start to first generation flight will likely mean an equally sporadic start to second generation. Many farmers will not be able to rely on a single biofix date and will instead have to track individual orchards as distinct cohorts of second generation codling moth emerge.

Brown marmorated stink bug pressure seems to be low so far this season, with only two individuals having been captured in traps in the region so far. We will continue to monitor for brown marmorated stink bugs until harvest is concluded, but risk for the west central region looks low at this time.

Second generation obliquebanded leafroller is flying, and timing for treatment is 400-450 growing degree days base 42 after you biofix an orchard. Second generation obliquebanded leafrollers caught many growers by surprise last year, so be on your guard for this pest this season.

European red mites are low this year in most orchards, the August threshold is 10-15 mites per leaf. San Jose scale crawlers are active at this time and products targeting them can be timed through the end of August. Third generation of oriental fruit moth is in flight. The timing for an application targeting oriental fruit moth is 200 growing degree days base 50 after you biofix an orchard.

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.

Ginger Gold

Growers of this variety need to give it at least another week before they think about harvest; fruits sampled this week were green, hard and starchy. Starch index values didn’t clear 1. Size looks good, and fruits have a nice touch of red blush on one side this year. This should increase with the good coloring weather in the next two weeks.  

Ginger Gold, Ludington area

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

115.47

5

4

1

16.5

20.4

10.3

0

0

1

2

127.5

5

4

1

21.8

21

9.8

0

0

1

3

131.4

5

4

2

25.6

20

11.1

0

0

1

4

199.2

5

4

1

18.4

17

12

0

0

1

5

152

5

4

1

17

18

12

0

0

1

6

178.7

5

4

1

21

20.2

11.3

0

0

1

7

97.8

5

4

1

20

20.5

9.9

0

0

1

8

120.6

5

4

1

17

19.8

9.5

0

0

1

9

194.74

5

4

1

18.3

20.2

10.1

0

0

1

10

148.2

5

4

1

21

24.2

10.9

0

0

1

AVE

146.561

5

4

1.1

19.66

20.13

10.69

0

0

1

McIntosh

Growers always harvest this variety early in west central Michigan, but even the most ambitious harvesters of McIntosh should be cooling the jets for at least a week or two. The target starch index for this variety for long-term controlled atmosphere (CA) storage is 5, and fruits this week were nowhere near that mark. Size is also quite small on McIntosh right now in many locations, further indicating that they need a couple of weeks to get better size before they make their way in to bins.

Hart area

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

125.8

15

4

1

16.2

16.6

9.8

0

0

2

2

89.9

15

4

1

19.2

18

10.9

0

0

2

3

143.1

10

4

1

16

15.4

10.2

0

0

2

4

194.7

10

4

4

16.2

15.6

9.9

0

0

2

5

118.4

5

4

3

16.2

15.7

10.5

0

0

2

6

132.4

10

4

1

18.4

17.9

10.4

0

0

3

7

115.2

5

4

1

15.8

17.6

10.5

0

0

2

8

88.1

15

4

1

19.5

15.5

10.3

0

0

2

9

113.7

15

4

1

21.8

17

10.2

0

0

2

10

104.9

10

4

1

18.2

17

10.6

0

0

2

Ave.

122.62

11

4

1.5

17.75

16.63

10.33

0

0

2.1

 

New Era area

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

106.7

5

4

1

15.2

16.3

11

0

0

2

2

137

5

4

1

16.2

16

11.2

0

0

3

3

114.5

5

4

1

19

20

12.1

0

0

1

4

117.8

5

4

1

16.7

15.2

10.4

0

0

2

5

146.6

5

4

1

18.6

14.8

10.7

0

0

1

6

109.7

5

4

1

11

16.7

11.2

0

0

2

7

129.8

5

4

1

15.2

15.2

10.2

0

0

3

8

116.2

5

4

1

17

15.4

9.8

0

0

1

9

141.1

5

4

1

16.2

19.2

9.8

0

0

2

10

124

5

4

1

15.2

16.2

9.5

0

0

2

Ave.

124.34

5

4

1

16.03

16.5

10.59

0

0

1.9

 

Ludington area

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

131.6

10

4

1

15.1

16.1

11

0

0

2

2

112

30

4

1

14.5

14.1

11.7

0

0

1

3

139.8

30

4

1

17.7

14.2

10.6

0

0

2

4

87.8

5

4

1

14.8

16.2

8.7

0

0

3

5

119.1

15

4

1

16

17.2

10.1

0

0

2

6

100.5

20

4

1

16.2

14.8

9.7

0

0

2

7

125.6

20

4

1

16.5

14.2

9.5

0

0

2

8

136.6

25

4

1

15.4

11.6

10.7

0

0

2

9

124.8

30

4

1

14.2

17

10.6

0

0

1

10

131.7

30

4

1

16.6

16

9.9

0

0

2

Ave.

120.95

21.5

4

1

15.7

15.14

10.25

0

0

1.9

Wildfire Gala

This is an early Gala strain that is relatively new to the region, so the results should NOT be viewed as representative of other Gala strains in the region. Normal season Galas will be sampled for the first time next week. This early season strain looked very nice this week, red color is outstanding and size was good. Fruits were starting to eat better this week, but still need another few days. This strain will fool you on maturity because color is so good, but it’s not ready yet. The target starch index value for Gala for CA storage is 3, and the average for the site tested this week fell well below that mark.

Mears area

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

166.3

70

1

1

22

19

11.2

0

0

1

2

135.2

60

3

2

22.8

21.5

11.4

0

0

2

3

137.9

75

1

1

19.5

20

11.6

0

0

4

4

164.5

55

1

1

20.3

17

12.8

0

0

3

5

165.4

90

2

2

18.3

18

12.1

0

0

2

6

111.9

60

3

1

24.67

24.3

12.5

0

0

1

7

121.2

60

3

2

22.5

23.8

11.6

0

0

1

8

126.6

80

2

2

21.2

24.3

11.5

0

0

3

9

142.1

90

1

2

18.3

18.5

12.3

0

0

2

10

143.9

85

1

1

19.8

19.3

12.1

0

0

3

AVE

141.5

72.5

1.8

1.5

20.937

20.57

11.91

0

0

2.2

SweeTango

This club variety is not represented on most area farms, but it is well known as an early season fresh market variety and provides a valuable benchmark for the timing of maturity on other prominent varieties in west central Michigan. Normally we would be moving into early SweeTango harvest in the next couple of days, but not this year. While this variety moved ahead significantly over the past several days, it still needs another week or more at all sites that were sampled this week. Red color will continue to improve with a few more days on trees. Size looks pretty good this year, and russet is low. This variety can have issues with fruit finish because the lenticels can be extremely sensitive and color can be tough to achieve, but overall it looks very nice at this time and will look even better in a week.

SweeTango, Elbridge area

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

224.9

60

3

3

15

16

12.8

0

0

1

2

146.1

50

3

1

20.8

17.2

12.5

0

0

1

3

136.4

50

3

3

16.7

19.2

11.2

0

0

2

4

182.7

55

3

1

17

16

10.4

0

0

2

5

112.1

55

2

1

19

16.4

10.8

0

0

1

6

149.6

60

3

2

17.4

22

11.3

0

0

3

7

133.87

45

3

1

18.1

17.5

10.5

0

0

1

8

126

45

2

1

18.3

18.6

9.9

0

0

1

9

156.2

65

3

1

19.3

20.3

9.9

0

0

1

10

114.2

60

3

2

18.1

20

9.9

0

0

1

AVE

148.207

54.5

2.8

1.6

17.97

18.32

10.92

0

0

1.4

 

SweeTango, Hart area, site 1

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

149.5

5

3

3

14.8

17.4

10.9

0

0

2

2

161

10

3

1

14.2

14.9

10.8

0

0

1

3

144.6

15

3

1

20

14.9

11

0

0

2

4

158

10

3

1

20

16.4

11.9

0

0

2

5

141.1

10

3

3

17.8

16.3

11.7

0

0

2

6

151.4

20

3

2

15.8

16.7

11.5

0

0

2

7

151.9

20

3

1

14.8

18.8

9.8

0

0

2

8

123.3

15

3

1

16.4

17.4

11.3

0

0

2

9

160.7

15

3

2

17.8

18.4

10.5

0

0

1

10

120.2

25

3

3

19

18.3

12.7

0

0

1

AVE

146.17

14.5

3

1.8

17.06

16.95

11.21

0

0

1.7

 

SweeTango, Hart area, site 2

Fruit No.

Weight (g)

Red (%)

Background Color

Russet

Pressure 1

Pressure 2

Brix (%)

Watercore

Bleeding

Starch Index

1

153.9

10

4

1

18.1

17

12.1

0

0

2

2

181.4

55

4

1

20

16

11.2

0

0

2

3

232.2

60

4

2

18

15

12.2

0

0

2

4

126.4

40

3

2

18.4

20.7

11.5

0

0

1

5

163

40

4

1

21.7

22.2

11.5

0

0

1

6

138.3

55

3

3

18.7

22.2

12.1

0

0

2

7

157.5

60

3

2

17.4

17.7

212.1

0

0

2

8

154.3

50

4

3

15.3

22.4

11.8

0

0

2

9

170.1

50

3

2

22.8

16.8

14.1

0

0

2

10

231.2

25

4

2

17.2

18

11.4

0

0

2

AVE

170.83

44.5

3.6

1.9

18.76

18.8

32

0

0

1.8

 

Suggested firmness and starch index levels for long-term and shorter-term storage by variety.   

Variety

Firmness (pounds)*

Starch Index*

Short CA

Mid CA

Long CA

Export CA

Mature

Over mature

Braeburn

16

17

18

 

3

7

Cortland

14

15

16

 

4

6

Empire

14

15

16

18

3.5

6

Fuji

16

17

18

 

3

7

Gala

16

17

18

 

3

6

Golden Delicious

15

16

17

 

3

6.5

Honeycrisp

15

16

17

 

3.5

7

Idared

14

15

16

 

3.5

6

Jonagold

15

16

17

 

3.5

5.5

Jonathan

14

15

16

 

3.5

5.5

McIntosh

14

15

16

 

5

7

Mutsu/Crispin

16

17

18

 

3

6

Northern Spy

16

17

18

 

3

6

Red Delicious

16

17

18

 

2.5

5

Rome

15

16

18

 

3

5.5

Spartan

17

18

19

 

4

6

Winesap

17

18

19

 

2.5

6

*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.)

 

 

Tags: 2019 apples, agriculture, apple maturity reports, apples, fruit & nuts, msu extension


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