The Right Cropload, Precision Apple Thinning · The Right Cropload, Precision Apple Thinning Philip...

1Philip Schwallier

The Right

Cropload,

Precision Apple

Thinning

Philip SchwallierDistrict Horticulture Agent

Clarksville Research Center

Precision Orchard Management

Precision Cropload

Management

nAdjusting cropload is most

important practice.

nPredicting Fruitset Model

Precision Crop Load ManagementIt is a Strategy to achieve a IDEAL number of

fruit/tree by using information and orchard

practices.

• Use pruning

• Use chemical thinning

• Gather & use information

• Use predictive models, Predicting Fruitset.

• Use hand thinning.

Prune to a 1.5x budload of target fruit/tree

Precision Crop Load Management

Steps Example

Tall Spindle

Apples/tree

Determine the IDEAL cropload. 100

Dormant prune to a specific

budload.

150 (1.5x)

Michigan’s Target Budload 2x or 200

Precision Thinning

• Initial Flower Load 400

clusters/tree

• Target Cropload, MI

100 fruit/tree

• Prune bud Load to 2x target 200

buds/tree

• WA= 1x, NY= 1.5x

Statewide Precision Thinning

Initial Flower Load 400 clusters/tree

Target Cropload, MI 100 fruit/tree

Therefore Target 1.5x

70% Underpruned 2x to 3x (5x)

30% Pruned close 1x to 1.25x

Chem Application 1 to 3 Apps

Hand Thinning 30%

A fruit bud

BeforeTarget 100/tree

500 clusters

AfterTarget buds

1.5x

Mark Clusters

n 15 clusters/tree on 5 trees

n 75 total clusters

n Pink to bloom

n Representative clusters

n Not high not low

Kim Kropf

Jill BlattnerBethany Blattner

Recording Fruitlet Diameters

for Fruitset Model 2013

Bridget Engelsma

Nicole Engelsma

Initial Flower Load

Bloom

Petal Fall

10 mm

16 mm

Target Fruit Number

Hand Thinning

Carb Model

Carb Model

Carb Model

Carb Model

Carb Model

Fruit Set Model

Fruit Set Model

Fruit Set Model

Precision Cropload Flow Chart

Predict if a Fruit Will Persist or Abscise

• Persist: A fruit was predicted to persist if the growth

rate over the measurement period was at least 50%

or greater of the fastest growing fruit.

• Abscise: A fruit was predicted to abscise if the

growth rate of the fruit slowed to 50% or less of the

growth rate of the fastest growing fruit.

DAYS AFTER NAA APPLICATION

0 2 4 6 8 10 12 14

FR

UIT

DIA

METER

(M

M)

8

10

12

14

16

18

20

22

Persist

Abscise

** *** *** ***

Predicting Percent Fruitset

Initial Flower Load

Bloom

Petal Fall

10 mm

16 mm

Target Fruit Number

Hand Thinning

Carb Model

Carb Model

Carb Model

Carb Model

Carb Model

Fruit Set Model

Fruit Set Model

Fruit Set Model


Natural Apple Background

Sensitivity to Thinning

We applied S+M and S+N every 3.5 days to

determine when thinning occurred.

Started at PF and ended 28 days later

To Gala for 8 years.

0

20

40

60

80

100

120

140

0 10 20 30 40 50

Pe

rce

nt

DAFB

Natural Apple Backgound Sensitivity to Thinning

Cropload Poly. (Cropload)

CROPLOAD = % FRUIT/TREE OF UTC DAFB=Days After Full Bloom

Pe

tal

Fall

6 m

m

8 m

m

10

mm

12

mm

15

mm

20

mm

24

mm

30

mm

Fu

ll B

loo

m

Nibble or Precision Thinning Concept

Precision Thinning

–Start thinning early

–Plan multiple sprays.

31Philip Schwallier

Initial Flower Load

Bloom

Petal Fall

10 mm

16 mm

Target Fruit Number

Hand Thinning

0 to 5%

10 to 20%

35%


5%

100 Apple/tree Target

Yet 400 cluster/tree or 2000 flowers/tree

Precision Thinning

We will often let the early thinning window go

by because we are unsure of fruit set.

– Trees and fruits are resilient

– Frost, bee activity, pollination, fertilization is

unknown.

– All make us unsure of set.

– Abundant initial flower numbers will follow with

abundant fruit numbers.

Philip Schwallier

Precision Thinning

Lets thin a little at every opportunity

Less Risk

More Success

More Confidence

35Philip Schwallier

0

20

40

60

80

100

120

140

0 5 10 15 20 25 30 35

Pe

rce

nt

DAFB

Natural Apple Backgound Sensitivity to Thinning

Fu

ll B

loo

m

CROPLOAD = % FRUIT/TREE OF UTC

Pe

tal Fa

ll

6 m

m

8 m

m

10

mm

12

mm

15

mm

20

mm

24

mm

Precision Thinning

Kim Kropf

Predicting Fruitset Project 2014

Precision Cropload

Management

n Start dormant, set target

n Prune to correct budload

n Thin early, Full Bloom and Petal Fall

Precision Cropload

Management

n Nibble the cropload down

n Use models and Information

n Re-thin where needed.

Mark Clusters

n 15 clusters/tree on 5 trees

n 75 total clusters

n Pink to bloom

n Representative clusters

n Not high or low in tree

Jill BlattnerBethany Blattner

Predicting Fruitset Project 2014

Theory of Fruitset

– Temperature affect demand of energy (carbon) from fruit and other tree growth.

– When fruitlets demand energy that exceeds supply, the weakest fruitlets drop.

– When energy is abundant, fruitlets set and resist thinning.

MaluSim Carbohydrate Model

n Carbohydrate Model of Cornell University

– Alan Lakso

– Terence Robinson

n Predicts Tree Carb Balance

– Max, Min, Solar Radiation, Latitude

MaluSim Sparta Carbohydrate Model 2013

-100

-80

-60

-40

-20

0

20

40

60

80

100

5/15 5/17 5/19 5/21 5/23 5/25 5/27 5/29 5/31 6/2 6/4 6/6 6/8 6/10 6/12 6/14 6/16

Ca

rbo

hy

dra

te B

ala

nce

MaluSim Sparta 2013

Carb Bal 4 Day Ave

Petal Fall

6 m

m

10 m

m

12 m

m

14 m

m

22 m

m

25 m

m

35 m

m

Full Bloom

72 62 73 33 25 7 22 0 0% Thinning

Stress Stress

No Stress

Honeycrisp Timing Thinning 2013

0

50

100

150

200

250

300

350

0

50

100

150

200

250

300

350

400

450

500

AFW (g)

Fruit/Tree

Cropload AFW

Petal Fall

6 m

m

10 m

m

12 m

m

14 m

m

22 m

m

25 m

m

35 m

m

Full Bloom

Stress Stress

No Stress

-80

-60

-40

-20

0

20

40

605

/15

/14

5/1

7/1

4

5/1

9/1

4

5/2

1/1

4

5/2

3/1

4

5/2

5/1

4

5/2

7/1

4

5/2

9/1

4

5/3

1/1

4

6/2

/14

6/4

/14

6/6

/14

6/8

/14

6/1

0/1

4

6/1

2/1

4

6/1

4/1

4

6/1

6/1

4

6/1

8/1

4

6/2

0/1

4

6/2

2/1

4

g c

arb

on

/da

ySparta Carb 2014 6-17-14

Balance 4 Day Ave

Petal Fall

6 m

m

10 m

m

14 m

m

24 m

m

26 m

m

28 m

m

32 m

m

Full Bloom

Thinning applications.

Full Bloom, #3 NAA 15 ppm, #4 Maxcel 100 ppm

All other treatments, Odd # S+N 1 pt + 15 ppm

Even # S+M 1 pt + 50 ppm

67 18 48 35 43 42 80 124 112Cropload

Stress StressNo Stress

0

50

100

150

200

250

300

350

0

50

100

150

200

250

300U

TC

HT

N 1

5

M 1

00

S+N

S+M

S+N

S+M

S+N

S+M

S+N

S+M

S+N

S+M

S+N

S+M

S+N

S+M

S+N

S+M

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

AFW (g)

Fruit/Tree

Honeycrisp Timing Thinning 2014

Fruit/Tree Ave Fruit Weight

Petal Fall

6 m

m

10 m

m

14 m

m

24 m

m

26 m

m

28 m

m

32 m

m

Full Bloom

Stress StressNo Stress

NAA 15 ppm Full Bloom Honeycrisp

MaxCel 100 ppm Full Bloom Honeycrisp

What is Precision Cropload

Management?

1. Set a Tartget Cropload/Tree.

2. Prune to a Precise Budload/Tree.

3. Start Chemical Thinning Early.

4. Use Models to Predict Set.

5. Repeat Chemical Thinning as needed.

6. Hand Thin

apples.msu.edu

SummaryIt is a Strategy to achieve a IDEAL number of

fruit/tree by using information and orchard

practices.

• Use pruning

• Use chemical thinning

• Gather & use information

• Use predictive models, Predicting Fruitset.

• Use hand thinning.

The Right Cropload, Precision Apple Thinning · The Right Cropload, Precision Apple Thinning Philip...

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