Making mass harvesters more productive with an

abscission agent

Jackie BurnsCitrus Research and Education

Center, UF-IFASjkbu@ufl.edu

(863) 956-1151

Citrus Research and Education Center

Continuous Canopy Shake and CatchTrunk Shake and Catch

Two types of mechanical harvestersare operating in Florida today

Citrus Research and Education Center

‘tractor-drawn’ canopy shaker

Citrus Research and Education Center

The tractor-drawn canopy shaker is also being used commercially in Florida.

Fruit are dropped to the ground and recovered by a hand ‘gleaning’ crew.

Citrus Research and Education Center

Fruit removal with mass harvesters is very good.

With an abscission agent, fruit removal will improve.

CMNP is a selective abscission agent- only loosens mature fruit

Can harvest 3 to 5 days after application

Easier fruit removal means- faster harvesting- successful late season harvest

Citrus Research and Education Center

Abscission increases speedof mechanical harvesting

Requirements:

‘selective’ abscission agenthigh volume applicationaverage force MH

Outcomes:

excellent uniform mature fruit removal2-4-fold increase in speed of removalincreased harvesting capacity

no abscission CMNP

Mat

ure

fru

it r

emo

val (

%)

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a

a

a a a

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1.0 mph

1.5 mph

2.0 mph

Citrus Research and Education Center

Abscission increases speed of mechanicalharvesting

Increasing MH capacity:

More fruit removedin the same time period(a day, a month, a season)

Canopy shaker harvestApril 19, 2004

Removing the impediment to late season harvest

• ~30% Valencia acreage remains to be harvested after May 1-processors: fruit delivered into June

• Mechanical harvesting past May 1st reduces yield thenext season by asmuch as 50%

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The problem:

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Abscission makes late seasonmechanical harvesting a success

Requirements:

‘selective’ abscission agenthigh volume applicationlow force MH

Outcomes:

excellent mature fruit removallow immature fruit removallittle yield reduction the next year

Citrus Research and Education Center

Late season Valencia mechanical harvestinga reality with low force + CMNP

70

75

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con

tro

l

+ a

bsc

con

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+ a

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han

dp

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ruit

re

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)

1.0

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4.8 Hz 8.0 Hz 4.8 Hz 8.0 Hz

Trunk shaker harvestMay 25, 2004

Yield – May 6, 2005a

bb

b

c

aaa

bb

Low force

5-chloro-3-methyl-4-nitro-1H-pyrazoleaka ‘CMNP’

What is CMNP, and what are theconsequences of its application?

Citrus Research and Education Center

•Harvest 3-5 days after application•Peel injury on blossom end•Injury restricted to flavedo

Valencia treated with 250 ppmCMNP, 5 days after application

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Juice quality and CMNP

Canopies were sprayed with CMNP, harvested 5 daysafter application, then held 5 days at 70oF

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Fractions and residues

Harvest 3-5 days after application

CMNP penetrates no further than the peel

CMNP rapidly metabolized to inactive compounds

The FDOC actively engaged in registration of CMNP• Studies that determine residues in fractions

are among the first conducted• If significant ‘red-flags’ are indicated, registration

will be abandoned• If this occurs, UF/IFAS has additional abscission

candidates to pursue

Citrus Research and Education Center

From AgroSource, Magnolia Consulting