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Managing Fruit Quality and Preharvest Drop
Tom Kon · Chris Clavet · JD Obermiller
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OutlineI. Preharvest Drop: Overview and Current
Management Recommendations
II. Evaluating alternative application strategies for aminoethoxyvinylglycine (AVG; Retain) in the SE
III. Effects and interactions of AVG (ReTain) and GA4+7 on ‘Gala’ fruit quality and cracking potential
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Objectives of Stop Drop Sprays• Preventing losses to preharvest drop
• Variety sensitivity• Fruit drop is variable from year-to-year• Yield loss of 30% is common at beginning of harvest (Arseneault
and Cline 2016)
• Marketing: early and late
• Fruit size targets
• Managing harvest• Scheduling labor• Varieties with similar harvest dates• Pick-your-own
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Delaying Harvest will Increase Fruit Size
20
30
40
50
60
70
80
60 80 100 120 140
Days after bloom
Me
an
fru
it d
iam
ete
r (m
m)
diameter increased only
0.3 mm per day
Gala (2008)
Slide from: S.A.McArtney et al.
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Management Options
• NAA (Fruitone L®; PoMaxa®; ReFine® 3.5WSG)
• AVG (ReTain®)
• NAA + AVG
• 1-MCP (Harvista™)
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NAA: Blocks Stem Loosening• Maturity is not delayed
• Maturity is often advanced
• Fruit respond in 2-3 days• “Rescue” option, but
• Doesn’t firm up those already loose
• 2 timings:• Just before drop starts: 10 to 20 ppm
• “pre-loading” 4 weekly sprays at 5 ppm
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NAA: Keys to Success
• Monitor drop and time spray accordingly
• Can be applied as part of cover sprays
• Avoid spraying in hot weather
• Split applications can help
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ReTain® (AVG): Ethylene Production Inhibitor
• Delays maturity:• Red color development
• Stem loosening
• Flesh softening, starch-sugar conversion
• Delays stem-end cracking, water core
• Delays Pre-harvest drop
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ReTain: Keys to Success
• Timing of spray• Split applications don’t help – single pouch
• Coverage and absorption• Use 100% organosilicone surfactant
• 100 GPA
• Best results in smaller trees
• Stressed trees are poor candidates
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Timing ReTain Sprays
• 4-3 weeks before anticipated harvest
• Early varieties: adjust harvest date estimate in early seasons
• Wait for good spray conditions and 6 hours drying time
• Delayed timing for multiple harvests• Targeting later pickings
• First pick is not delayed
• Apply 1-2 weeks before start of harvest
• Rate: 1 pouch – label change permits up to 2 pouches/acre
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NAA + AVG: Provides greatest drop control and control of fruit softening (McArtney et al.)
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Harvista™
• Sprayable formulation of 1-MCP
• Delivered through a proprietary in-line injection system
• Application timing based on starch index; cv dependent
• Some Henderson County, NC growers used in 2017
If interested contact:Nancy Brill [email protected] [email protected]
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Objectives
Determine the efficacy of double pouch ReTain (AVG) programs on fruit drop and fruit quality of: Red Delicious and Auvil Fuji
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0
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70
80
JUL AUG SEP OCT NOV
Tem
per
atu
re (
F)Average Monthly Temperature – Mills River, NC
10 Year Avg. 2017 Average
00 6 21
Number of days with low temperatures < 50 F in 2017
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Treatments applied to ‘Oregon Spur II Red Delicious’/‘M. 111’
Treatment ID Formulation No. of Applications
1 Control 0
2 ReTain® (333 g/acre) 1
3 ReTain® (333 g/acre) 2
Treatments were applied to two tree plots (6 replicates) using a tractor mounted, pto-driven air blast sprayer calibrated to apply 100 gallons per acre
All chemical treatments were applied in an aqueous solution with 0.1% (v:v) organosilicate surfactant (SYL-COAT®; Wilbur-Ellis; Aurora, CO).
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0
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50
60
-1 0 1 2 3 4 5 6
Cu
mu
lati
ve f
ruit
dro
p (
%)
Weeks after normal harvest
Effects of Application Rate on Cumulative Fruit Drop
Control ReTain: 3 WBAH ReTain: 3+1 WBAH
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Effect of application number of aminoethoxyvinylglycine (AVG) on firmness of
'Oregon Spur II Red Delicious' apples in 2017.
Fruit firmness (lb.)
Formulation No. Applications 9 Sept. 20 Sept. 29 Sept. 4 Oct. 12 Oct.
Control -- 15.7 14.4 13.1 12.4 12.3
ReTain 1 16.1 15.2 14.3 13.4 12.5
ReTain 2 16.3 15.7 15.0 14.1 13.4
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Effect of application number of aminoethoxyvinylglycine (AVG) on starch rating of
'Oregon Spur II Red Delicious' apples in 2017.
Starch rating (1-8)
Formulation No. Applications 9 Sept. 20 Sept. 29 Sept. 4 Oct. 12 Oct.
Control -- 4.3 6.9 7.3 7.5 7.6
ReTain 1 4.0 6.2 7.0 7.3 7.6
ReTain 2 3.7 5.5 6. 7.0 7.5
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Objectives• Effect of application rate and timing of
aminoethoxyvinylglycine (AVG) on fruit quality and fruit drop on ‘Auvil Fuji' apples
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Treatments applied to ‘Auvil Fuji’ apple trees.
Treatment ID Formulation No. of
Applications
Application Timing
1 Control 0 --
2 ReTain® (666 g/acre) 1 2 WBH
3 ReTain® (666 g/acre) 1 4 WBH
4 ReTain® (333 g/acre) 2 2 + 4 WBH
Treatments were applied to two tree plots (6 replicates) using a tractor mounted, pto-driven air blast sprayer calibrated to apply 150 gallons per acre
All chemical treatments were applied in an aqueous solution with 0.1% (v:v) organosilicatesurfactant.
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0
10
20
30
40
50
60
0 1 2 3 4 5 6 7
Cu
mu
lati
ve f
ruit
dro
p (
%)
Weeks after normal harvest
Effects of Application Rate and Timing on Cumulative Fruit Drop
Control ReTain 2WBH ReTain 4WBH ReTain 2+4WBH
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Effect of application timing of aminoethoxyvinylglycine (AVG) on firmness of ‘Auvil Fuji' apples in 2017.
Fruit firmness (lb.)
Formulation Timing 29 Aug. 5 Sept. 12 Sept.
Control -- 13.8 13.6 12.6
ReTain 2 WBH 14.1 13.8 13.3
ReTain 4 WBH 14.1 13.9 13.3
ReTain 2 + 4 WBH 13.9 13.9 13.1
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Effect of application timing of aminoethoxyvinylglycine (AVG) on starch rating of ‘AuvilFuji' apples in 2017.
Starch rating (1-8)
Formulation Timing 29 Aug. 5 Sept. 12 Sept.
Control -- 6.1 7.0 7.3
ReTain 2 WBH 5.9 6.9 7.2
ReTain 4 WBH 6.1 6.9 7.5
ReTain 2 + 4 WBH 6.0 7.1 7.2
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ObjectiveDetermine effects and interactions of application number and rate of aminoethoxyvinylglycine (AVG) and GA4+7 (ProVide) on fruit quality and stem-end cracking of ‘Gala'
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Treatments applied to ‘Ultima Gala’ apple trees.
Treatment ID Formulation No. of
Applications
1 Control 0
2 ReTain® (83 g/acre) 3
3 ReTain® (110 g/acre) 3
4 ReTain® (167 g/acre) 3
5 ProVide (50 ppm) 3
6 ReTain® (83 g/acre) + ProVide (50 ppm) 3
7 ReTain® (110 g/acre) + ProVide (50 ppm) 3
8 ReTain® (167 g/acre) + ProVide (50 ppm) 3
9 ReTain® (167 g/acre) 1
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Main effects• GA4+7 (ProVide) did not influence stem end splitting
or any other response in this trial
• AVG (ReTain) was an influential factor
There was no relationship between AVG and stem end splitting at HO…
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40
0 0.1 0.2 0.3 0.4 0.5
Inci
de
nce
of
ste
m e
nd
sp
litti
ng
(%)
ReTain rate
Effect of application number and rate on stem end splitting
H2 Retain H2
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0 0.1 0.2 0.3 0.4 0.5
Inci
den
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sp
litti
ng
(%)
Retain rates
Effect of application number and rate on stem end splitting
H2 Retain H2 H4 Retain H4
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0 0.1 0.2 0.3 0.4 0.5
Inci
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f st
em e
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sp
litti
ng
(%)
ReTain Rate
Effect of application number and rate on stem end splitting: bucket test
H3 ReTain H3 H5 ReTain H5
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1
2
3
4
5
6
7
8
0 0.1 0.2 0.3 0.4 0.5
Star
ch r
atin
g (1
-8)
Retain Rates
Effect of Application Number and Rate on Starch
H0 Retain H0 H2 Retain H2 H4 Retain H4
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Effect of application number and rate of aminoethoxyvinylglycine (AVG) on firmness of ‘Gala' apples in 2017.
Fruit firmness (lb.)
Formulation Rate 17 Aug. 30-Aug 14 Sept.
Control -- 16.0 13.8 --
ReTain 83 g/A 18.0 16.2 13.6
ReTain 110 g/A 17.5 15.5 13.6
ReTain 167 g/A 17.8 16.0 14.7
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Summary
• Double pouch ReTain programs showed promise in delaying fruit maturity and preharvest drop• Pending upon labor availability, market,
• Applying double pouch (or single) ReTain too late will reduce product efficacy• Can be a challenge in years with advanced maturity• Addition of NAA?
• Multiple applications of low rates of ReTainreduced stem-end splitting potential and delayed maturity• GA4+7 did not
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Acknowledgements• Greg Nix – Apple Wedge Packers
• Richard Staton – RichmindOrchards
• Valent USA
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Thank you for your attention!!