Control of fruit drop and harvest management in apples

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Control of fruit drop and harvest management in
apples

• Rongcai Yuan
• AHS Agricultural Research and Extension Center,
  Virginia Tech

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Control of Pre-harvest Fruit Drop in Apples
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Introduction

• Pre-harvest fruit drop Apple fruit abscise
  before adequate color or maturity develops.
• It usually causes a serious economic loss.

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Introduction

• Cultivars susceptible to dropping Delicious,
  York, Rome, Stayman, Golden Supreme, Honeycrisp,
  Golden Delicious, etc.
• Picking fruit before adequate maturity may lead
  to poor storability and poor fresh and processed
  fruit quality.
• Early harvest can also result in lower yields and
  prices since fruit will increase in weight 5 to
  7 per week and price is based on larger fruit
  sizes (Byers and Eno, 2002).

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Introduction

• Delaying preharvest fruit drop while maintaining
  fruit quality by chemical sprays can extend
  harvest window.
• It is good for the arrangement of labor,
  harvesting tools such as picking bin and trucks,
  and cold storage equipment.
• It is also good for pick your own orchards,
  farmers market and fruit stands.

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Why does preharvest fruit drop occur?

• Fruit ethylene production increases when fruit
  ripen.
• Plant hormone auxin is low in fruit.
• Fruit drop increases with increasing ratio of
  ethylene to auxin.
• High ethylene also causes fruit softening.

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Factors affecting preharvest fruit drop

• Cultivars Fuji, Pink Lady and Granny Smith have
  no or little preharvest fruit drop.
• Warm weather increases fruit drop.
• Drought stress will increase fruit drop by
  accelerating fruit ethylene production.

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Compounds used to delay fruit drop

• Two registered plant growth regulators NAA
  (Fruitone) and AVG (ReTain).
• Sprayable 1-MCP (Harvista) will be available soon.

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Fruitone (NAA)

• NAA is an artificial auxin.
• NAA is effective for 7 to 10 days after treatment
  and is inadequate for Delicious and other
  apples.
• Two applications of NAA
• or warm weather following
• the first application usually
• accelerate fruit ethylene
• production and fruit
• softening.

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ReTain (AVG)

• AVG (ReTain), an inhibitor of ethylene
  biosynthesis, can suppress ethylene production,
  delay fruit ripening, and reduce pre-harvest
  fruit drop when applied within 1 month of
  harvest.
• In some years, AVG may be not very effective as a
  drop control compound for apples such as
  Delicious, York, and Golden Delicious.

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Harvista (sprayable1-MCP)

• Sprayable 1-MCP is an action inhibitor of
  ethylene, and more effectively reduces preharvest
  fruit drop than AVG or NAA in Delicious.
• We found that the combination of NAA and AVG or
  1-MCP more effectively reduced preharvest fruit
  drop than did NAA, AVG, or 1-MCP alone while
  maintaining fruit firmness in Delicious,
  Golden Delicious and Golden Supreme.

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Control of Pre-harvest Fruit Drop

• Golden Supreme apples

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NAA and ReTain (AVG) on Fruit Drop of Golden
Supreme
NAA4 NAA applied 4 weeks before harvest NAA2
NAA applied 2 weeks before harvest AVG4 AVG
applied 4 weeks before harvest AVG2 AVG applied
2 weeks before harvest NAA at 8 oz/100 gal. AVG
at 11.7 oz/100 gal. Anticipated harvest date was
30 August in Winchester, VA
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Golden Supreme
Control
NAA42 AVG4
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NAA and AVG on fruit ethylene in Golden Supreme
apples
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Effects of AVG and NAA on fruit quality of
Golden Supreme applesX
XAnticipated harvest date was 30 Aug. 2005.
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NAA and AVG on fruit weight
Fruit weight increased 16 from Aug. 30 to Sept.
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Control of Pre-harvest Fruit Drop

• Delicious apples

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NAA, AVG, and Sprayable 1-MCP on Fruit Drop of
Bisbee Delicious - 2006
NAA applied 2 1 weeks before harvest AVG
applied 2 weeks before harvest 1-MCP applied 2
weeks before harvest Anticipated harvest date
was Sept. 21 NAA at 8 oz/100 gal. AVG at 11.7
oz/100 gal. 1-MCP at 160 ppm
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NAA, AVG, and Sprayable 1-MCP on Fruit Ethylene
of Red Delicious - 2006
NAA 2 1 weeks BH AVG 2 weeks BH 1-MCP 2
WBH NAA at 8 oz/100 gal. AVG at 11.7 oz/100
gal. 1-MCP at 160 ppm
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NAA, AVG, and Sprayable 1-MCP on Fruit Color-2006
xAnticipated commercial harvest date was 21 Sept.
2006. yMean separation within columns by Duncans
multiple range test, P lt 0.05.

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NAA, AVG, and Sprayable 1-MCP on Fruit firmness
(lb) -2006
xAnticipated commercial harvest date was 21 Sept.
2006.
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Preharvest application of PGRS on Delicious
apple fruit quality after 3 months RA storage
xAnticipated commercial harvest date was 21 Sept.
2006. yFruit were harvested on 21 Sept., 28
Sept., 4 Oct. and 11 Oct., 2006, respectively.
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Preharvest application of PGRS on Delicious
apple fruit quality after 6 months RA storage
xAnticipated commercial harvest date was 21 Sept.
2006. yFruit were harvested on 21 Sept., 28
Sept., 4 Oct. and 11 Oct., 2006, respectively.
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Delicious Fruit drop - 2007
Weeks before anticipated harvest date which was
19 Sept. 2007
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Effect of AVG and NAA on the return of
Delicious apples
ZAVG 250 per acre, NAA 20 per acre, cost for
spray 50 per acre.
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Control of Pre-harvest Fruit Drop

• Golden Delicious

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NAA, AVG, and Sprayable 1-MCP on Fruit Drop of
Golden Delicious - 2005
NAA, AVG, and 1-MCP applied on Sept. 21, one week
before harvest NAA at 8 oz/100 gal. AVG at 11.7
oz/100 gal. 1-MCP at 396 ppm
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Golden Delicious
Oct. 24, 2005
Control
1-MCP
NAA AVG
NAA
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Summary

• The combination of ReTain and NAA applied 4 and 2
  weeks BH, respectively, had a better effect than
  NAA or ReTain alone in reducing preharvest fruit
  drop.
• NAA stimulates fruit softening, but the
  combination of ReTain and NAA had better fruit
  quality than control or NAA alone.

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Advancing fruit ripening and increasing red color
with ethephon
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Ethephon and AVG on Pink Lady
Ethephon at 280 ppm applied 2 weeks before
harvest AVG at 125 ppm applied 5 weeks before
harvest
Whale et al. 2008 from Australia
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Ethephon on McIntosh apples
Flesh firmness (lb)
Red color ()
Ethephon (ppm)
0 (Control)
35 c
14.8 a
57 b
14.3 b
125
250
73 a
14.2 b
Ethephon was applied on 11 Aug. and fruit were
harvested on 25 Aug.
Greene et al., 1977
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NAA and AVG on fruit drop caused by ethephon in
Delicious apples
Ethephon, NAA, AVG were applied on 15 Sept.
Byers, 1997
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Summary

• Ethephon should be applied between 1 and 3 weeks
  before normal harvest or 1 to 2 weeks before
  desired harvest date at concentration from 125 to
  270 ppm.
• Increased color will be noted within 5 -7 days
  after ethephon treatment.
• NAA at 10 to 20 ppm is used to reduce fruit drop
  caused by ethephon.
• Ethephon-treated fruit have a shorter storage
  life than regular fruit.

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Delaying fruit ripening in apples
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AVG and 1-MCP on Imperial Gala apples
xDays before anticipated harvest date which was
27 Aug. 2007.
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Summary

• AVG or sprayable 1-MCP can effectively delay
  fruit ripening, thereby extending harvest window.

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Acknowledgement

• David H. Carbaugh
• Amelia G. Engelman

• Virginia Apple Research program
• Virginia Agricultural Council

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THANK YOU !HAVE A GOOD YEAR!