1. Al Kovaleski February, 2014 Summer pruning southern highbush blueberries in Florida University of Florida Horticultural Sciences Department

2. Blueberry summer pruning 2 No removal of flower buds Long growing season in FL Pruning promotes increased vigor More support for reproductive structures

3. Objectives 3 Determine the effects of timing and severity of summer pruning: Vegetative traits: Regrowth Cane breakage Timing of defoliation Incidence of leaf spots Incidence and severity of stem blight Reproductive traits: Flower bud initiation Fruit set Yield Quality of fruit

4. Plant material 4 Two cultivars ‘Emerald’ and ‘Jewel’ Seven year old plants Commercial cultural practices PSREU – Citra, FL

5. Treatments 5 No summer pruning control Prune 30% early June Prune 30% mid-July Prune 30% early June+tip Prune 60% early June+tip Detailed hand pruning control www.caes.uga.edu

6. Treatments 6 30%60%Unpruned

7. Vegetative traits 7 Canopy volume Regrowth Condition of fall foliage Time of defoliation Leaf spot

8. Vegetative traits 8 Incidence and severity of Stem Blight

9. Reproductive traits 9 Re-growth shoots collected to assess timing of flower bud initiation – Late summer until defoliation

10. Reproductive traits 10 Harvest Period Yield Fruit quality Total soluble solids Titratable acidity Firmness Average berry weight picturesbychristopher.wordpress.com Labmate-online.com

11. R ESULTS TO DATE 11

12. Regrowth volume - Jewel 12

13. Cane breakage - Freezes 13

14. Leaf spots - Jewel 14

15. Environmental Conditions 15 2011201220132014

16. Leaf spots - Jewel 16

17. Defoliation - Jewel 17 No significant defoliation in ‘Emerald’ until December

18. Flower bud initiation 18

19. Flower bud initiation 19

20. Flower bud initiation 20 Emerald – Sep 8 th Jewel – Oct 20 th

21. Flower bud initiation 21 Important: Develop management strategies to enhance flowering Regulate fruit load Yield! First sign of transition detectable

22. Stem blight 22 Jewel was not affected No differences among treatments in Emerald 25% incidence

23. Berry quality 23 Average weight - Jewel Reduction in the 60%+tip 1.9g  1.4g Others averaged 1.7g pH, acid and sugar content, anthocyanins, firmness No differences

24. 24 Yield - Emerald

25. Yield - Jewel 25

26. Yield - Jewel 26

27. Acknowledgements 27 Dr. Darnell and Dr. Williamson Dr. Olmstead and Dr. Harmon

28. 28 Thank you!