Innovative ThinKingProgress with Two

Mechanical Fruit Thinners

Jim Schupp and Tara Baugher Penn State University

Steve MillerUSDA-ARS

2009

GOAL: To Increase Crop Valueby Reducing Hand Thinning

and Increasing Fruit Size

GOAL: To Increase Crop Valueby Reducing Hand Thinning

and Increasing Fruit Size

o4 mechanical thinner prototypes

oPeach trees trained to perpendicular V (2007, 2008) or vase (2008)

Horticultural and Economic Evaluations

May 2008 covers: AFG, WFG & FGN

White Lady

Blossom Thinned with String Thinner

Hand Thinned

USDA Specialty CropResearch Initiative

Innovative Technologies for Thinning of Fruit PSU, UC Davis, Clemson, WSU, UMD, UIL, USDA

Non-Selective and Selective Thinning

Non-Selective Thinning Investigations

In Cooperation with WSU, UC Davis, Clemson, USDA

o Mechanical Thinning at Various Bud Stageso Modifying Pruning Practices to Improve Access by

Mechanical Thinnerso Various combinations of labor efficient thinning

methods

2009 – First Year of Trials for Multi-State Cooperators

-Second Year of Trials in 12 PA Orchard Blocks

New String Technology 2009

Four On, Four Off

VarietyRotations

Per Minute

Miles Per Hour

Red Haven 200 1

2 On, 2 Off

Variety TimingRotations

Per Minute

Miles Per

Hour

White Lady Pink 150 &

180 2

PF 17 Pink 180 2

2 On, 2 Off Opposing

Variety TimingRotations

Per Minute

Miles Per

Hour

Red Haven Pink 160 1

New Strings Compared to OldPerp V

Upper Lower Upper Lower Upper Lower0

5

10

15

20

25

30

35

40

45

2 on 2 off, opposing sides, 150 rpm

2 on 4 off, 180 rpm (old strings)

2 on 2 off, opposing sides, 180 rpm

Scaffold Portion

Perc

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f Blo

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New Strings Compared to OldVase

Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower0

10

20

30

40

50

60

70

4 on 4 off, 200 rpm (old strings)

2 on 2 off, 150 rpm

Full 9 strings, 150 rpm

Selected Branch

Perc

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Timing Study- 2008

• Blossom thinning with the string thinner more effective between 20% bloom and petal fall than at earlier bud stages – Flower removal– Fruit set– Hand thinning requirement

• All timings effective for increasing fruit size

Timing Study 2009

1. Hand thinned control2. String thin, 80% bloom3. String thin, pink, 1 pass4. String thin, pink, 2 passes5. String thin, petal fall

String Thinner Timing2009

Flowers Set Hand thin0

5

10

15

20

25

30

35

40

45

80% FBP 150P 120PF%

Red

uctio

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Timing Summary 2008-09

• Easier visual assessment of flower removal when bloom is open

• Pink (08): greater set - similar increase in size• Pink (09): more thinning than at 80% bloom• PF (09): more effective than earlier stages

Pruning Studies 2008-09Perpendicular V1. Standard, HTC2. Standard3. Fan4. Partial5. Detail6. Non-pruned

Open Center7. Standard, HTC8. Standard9. Partial10. Detail

Pruning EffectsPerp. V 2009

Flowers Set Hand Thinning0

10

20

30

40

50

60

NoneStandardDetail

Pruning EffectsOpen Center 2009

Flowers Set Hand Thinning0

10

20

30

40

50

60

70

PartialStandardDetail

Perpendicular V and Open Center

Most Consistent Results

Detail Pruning

New Drum Shaker

Thinning Combinations, 2009

1. Hand thinned control2. String thin, 60% bloom3. NEW Drum Shaker, 60% bloom4. NEW Drum Shaker, 35 DAFB5. NEW Drum Shaker, 60% B + 35 DAFB

Peach Drum Shaker 2009

Fruit set Hand thinning time0

5

10

15

20

25

30

35

40

45

DS 35 DAFBDarwin 60 BDS 60 BDS 60B + 35%

Red

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Combinations Summary 2008-09

• String thinner at bloom / drum shaker for green fruit thinning an effective combo

• Need more work on drum shaker at bloom / drum shaker for green fruit thinning

• New drum shaker at green fruit stage more consistent than previous citrus shaker prototypes– Smaller rods, tilting drums, front or side-mount

Implications for Growers

• Mechanical thinners are consistent in both reducing labor costs and increasing fruit size

• Blossom thinning with string thinner is viable and commercially available option

• Green fruit thinning with drum shaker is promising/ under development

• In future, combinations of bloom and fruit thinners may – help growers better target fruit loads with little hand thinning– Reduce risk of over-thinning

Penn State College of Agricultural Sciences research, extension, and resident education programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.

Where trade names appear, no discrimination is intended, and no endorsements by Penn State Cooperative Extension is implied.

This publication is available in alternative media on request.The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. It is the policy of the University to maintain an academic and work environment free of discrimination, including harassment. The Pennsylvania State University prohibits discrimination and harassment against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, gender identity, or veteran status. Discrimination or harassment against faculty, staff, or students will not be tolerated at The Pennsylvania State University. Direct all inquiries

regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 328 Boucke Building, University Park, PA 16802-5901; Tel 814-865-4700/V, 814-863-1150/TTY.

J. Schupp1,T. Auxt Baugher2, S. Miller3, K. Ellis2, Edwin Winseler1,

K. Reichard1, J. Remcheck2, S. Wolford3, M. Schupp1, C. Musselman2, A. Leslie2, R. Rohrbaugh2, J. Koan2, C. Anders2, E. Moore1, T. Kon1, C.

Kuntz1

1Penn State Fruit Research and Extension Center, Biglerville, PA2 Penn State Cooperative Extension in Adams County, Gettysburg,

PA3 USDA-ARS Appalachian Fruit Research Station, Kearneysville, WV

The authors acknowledge the valuable contributions of

A. Betz, S. Betz, D. Kilmer, R. Fitzpatrick, P. Baugher, S. Aguilar, C. Baugher, J. Cline, A. Diaz, B. Hollabaugh, D. Kuhn, K. Lesser,

J. Lott, D. Lott, C. McCleaf, D. Mickey, E. Rankin, T. Salada, D. Wenk, and B. Wenk The authors greatly appreciate the financial support of

The State Horticultural Association of Pennsylvania Extension Committee, the Washington State Tree Fruit Research Commission,

The USDA Specialty Crops Research Initiative Program, the Pennsylvania Department of Community and Economic Development First

Industries Program, the Penn State College of Agriculture Seed Grant and Sunday Grant Programs,

the Pennsylvania Peach and Nectarine Board, the California Canning Peach Association, and the Robert C. Hoffman Foundation

For more information, please visit

http://www.abe.psu.edu/scri/