This is a summary of two years of research in Pennsylvania on Mechanical String Thinners to remove blossoms.

1. Innovative ThinKingProgress with Two Mechanical Fruit Thinners Jim Schupp and Tara Baugher Penn State University Steve Miller USDA-ARS 2009

2. GOAL: To Increase Crop Valueby Reducing Hand Thinning and Increasing Fruit Size

4. Peach trees trained to perpendicular V (2007, 2008) or vase (2008) Horticultural and Economic Evaluations

6. May 2008 covers: AFG, WFG & FGN

7. White Lady Hand Thinned Blossom Thinned with String Thinner

8. USDA Specialty CropResearch Initiative Innovative Technologies for Thinning of Fruit PSU, UC Davis, Clemson, WSU, UMD, UIL, USDA Non-Selective and Selective Thinning

10. Modifying Pruning Practices to Improve Access by Mechanical Thinners

13. 2009 – First Year of Trials for Multi-State Cooperators-Second Year of Trials in 12 PA Orchard Blocks

14. New String Technology 2009

15. Four On, Four Off

16. 2 On, 2 Off Opposing 2 On, 2 Off

17. New Strings Compared to OldPerp V

18. New Strings Compared to OldVase

19. 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

20. Timing Study 2009 Hand thinned control String thin, 80% bloom String thin, pink, 1 pass String thin, pink, 2 passes String thin, petal fall

21. String Thinner Timing2009

22. 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

23. Pruning Studies 2008-09 Perpendicular V Standard, HTC Standard Fan Partial Detail Non-pruned Open Center Standard, HTC Standard Partial Detail

24. Pruning EffectsPerp. V 2009

25. Pruning EffectsOpen Center 2009

26. Perpendicular V and Open Center Most Consistent Results Detail Pruning

27. New Drum Shaker

28. Thinning Combinations, 2009 Hand thinned control String thin, 60% bloom NEW Drum Shaker, 60% bloom NEW Drum Shaker, 35 DAFB NEW Drum Shaker, 60% B + 35 DAFB

29. Peach Drum Shaker 2009

30. 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

31. 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

32. 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. Kuntz11Penn 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 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.

33. The authors acknowledge the valuable contributions ofA. 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 ofThe 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

34. For more information, please visithttp://www.abe.psu.edu/scri/