1. Squash Tolerance to Sandea and Applying Sandea Through Drip Tape Dr. Ted Webster Weed Scientist USDA-ARS Tifton, GA

2. Purple and Yellow Nutsedges: Primary Weeds in a Plasticulture System

3. What Did We Want to Find Out? Will Sandea injure squash?Will Sandea injure squash? Does application method matter?Does application method matter? What kind of nutsedge control can we expect?What kind of nutsedge control can we expect?

4. Greenhouse Study Squash cultivars:Squash cultivars: –3 zucchini –2 yellow crookneck –1 yellow straightneck Rates of Sandea:Rates of Sandea: –0.33 oz/A –0.66 oz/A –1.00 oz/A Application Methods:Application Methods: –PRE –POST –Split Planting Methods:Planting Methods: –Transplants –Direct Seeded

5. Visual Squash Injury (32 DAP) Sandea __ Direct Seeded __ ____ Transplant ____ (oz/A)PREPOSTSplitPREPOSTSplit ___________ % Visual Crop Injury ___________ 0.33 15 c 13 c 15 c 14 c 13 c 0.66 23 b 17 bc 22 b 17 bc 12 c 15 c 1.00 35 a 19 bc 33 a 17 bc 13 c 32 DA-PRE, 16 DA-POST **

6. Sandea Applied PRE to Direct-Seeded Zucchini Squash (Tigress) 0.33 oz/A 1.0 oz/ANontreated Control

7. Visual Squash Injury (32 DAP) Squash Cultivar Direct Seeded Transplant ___ % Visual Crop Injury ___ Dixie (cn) 20 c-e 18 c-g Lemondrop (sn) 18 c-f 13 g-l Senator (z) 17 c-h 14 f-k Spineless Beauty (z) 24 ab 13 h-l Supersett (cn) 28 a 13 h-l Tigress (z) 21 bc 15 e-i * * * *

8. 60 Lb. Pressure Valve Air Relief Valve Backflow Valve Low Pressure Drain Filter Pressure Regulator (20 lb) DRIP TAPE INJECTION SYSTEM Tifton, GA Pump (125 ml/min) Field Studies

9. Treatments (Applied 14 days prior to transplanting/seeding) Metam (75 gal/A) Non-treated: Black Plastic mulch Non-treated: Bareground Sandea (PRE) – prior to laying plastic Sandea (Drip) – applied through Drip Tape –0.75 oz/A in 1 gal. of water, injected for 30 min. –Flush system for 1 hour Webster 2000 & 2001

10. Field Study: Crop and Weed Responses CropNutsedge(shoots/plot)Treatment Diameter (cm) Early Season Late Season Sandea:Drip47* 2* 2* 28* 28* Sandea:PRE45* 4* 4* 38* 38* Metam58 1* 1* 27* 27* Non-treated49*15*113 Bareground42*71 ___ ___ PLSD 0.05 716 52 52

11. MetamSandea PRE Sandea: DripNontreated Bare Ground Nontreated

12. Field Study: Total Crop Yields (lbs/plot) 20002001TransplantSeededTransplantSeeded Sandea:Drip 31 31 34* 34* 75 75 58* 58* Sandea:PRE 25* 25* 32* 32* 62* 62* 51* 51* Metam 37 37 42 42 89 89 78 78 Non-treated 28* 28* 27* 27* 67* 67* 55* 55* Bareground 11 11 1 45 45 37 37 PLSD 0.05 ________ 8 ________ ________ 8 ________ __________ 16 __________ __________ 16 __________

13. Culpepper 2001

15. PRE 20 DAE 30 DAE 10 DAE

16. Conclusions Sandea caused early season squash injury.Sandea caused early season squash injury. Variable response of squash to Sandea:Variable response of squash to Sandea: –Greenhouse: Early growth of transplanted squash more tolerant of Sandea than direct- seeded squash. –Field: Differences among planting methods in response to Sandea were not detected in terms of crop yield. –Field: Older/larger plants appear to be more tolerant of Sandea applications.

17. Conclusions Preliminary: similar nutsedge suppression from: Metam (75 gal/A) and Sandea (0.75 oz/A); Is tuber population affected?Preliminary: similar nutsedge suppression from: Metam (75 gal/A) and Sandea (0.75 oz/A); Is tuber population affected? Early season: 80% fewer nutsedge shoots in black plastic UTC vs. bareground UTCEarly season: 80% fewer nutsedge shoots in black plastic UTC vs. bareground UTC

18. What’s next? Future research questions Will Sandea through drip tape kill emerged nutsedge ?Will Sandea through drip tape kill emerged nutsedge ? Will cucurbits tolerate POST Sandea applications through drip tape?Will cucurbits tolerate POST Sandea applications through drip tape? How many purple nutsedge does it take to reduce squash yields?How many purple nutsedge does it take to reduce squash yields?

19. Acknowledgements We acknowledge the technical skills and efforts of James Davis in coordinating these studies.We acknowledge the technical skills and efforts of James Davis in coordinating these studies. We also thank Eddie Sklany and the numerous student workers for their assistance in plot establishment and harvest.We also thank Eddie Sklany and the numerous student workers for their assistance in plot establishment and harvest. This work was supported in part by the IR-4 Minor-Use Crops Research Project.This work was supported in part by the IR-4 Minor-Use Crops Research Project.