1. Non-Selective Herbicides for Winter Weed Control in Non-overseeded Bermudagrass Dr. Tim R. Murphy Extension Weed Specialist University of Georgia Griffin

2. Traditional Control Program l Triazine - based l Annual broadleaf weeds + annual bluegrass l Flexible application timing l Low in cost

3. Triazine Issues l Under special review - EPA l Toxicological implications l Triazine-resistant weeds l Ground and surface water detects l Chattahoochee River study - USGS

4. Chattahoochee - USGS

5. 2,4-D Controversy l Non-Hodgkins Lymphoma

6. Need for Alternatives

7. Non-Selective, Non-Residual l Broad spectrum l Fast-acting - Reward LS, Scythe l Slow-acting - Roundup Pro l No soil residual l Repeat applications ?? l Effect on spring transition

8. Non-selective Options l Roundup Pro - glyphosate l Reward LS - diquat l Finale - glufosinate l Scythe - pelargonic acid

9. Scythe l Fast-acting, membrane disrupter l Soil persistence - < 2 days l Rate - 5 to 10% v/v l Applications at < 60 F. may be less effective

10. Reward LS l Fast-acting, membrane disrupter l Soil persistence - T1/2 = 1,000 days l Immobile in soil l Sorption - almost irreversible l Rate - 0.25 to 0.5 lbs. ai/acre

11. Roundup Pro l Slow acting, inhibits amino acid synthesis l Soil persistence - T 1/2 = 47 days l Very low leaching potential l Rapid adsorption to soil l Rate = up to 0.5 lbs. ai/acre

12. Finale l Intermediate activity l Inhibits nitrogen metabolism l Soil persistence - T 1/2 = 7 days l Highly mobile in soils l Rapid microbial degradation l Rate - 0.5 to 1.5 lbs. ai/acre l NL in dormant turf - 1997

13. Effect of dormant applications on green-up NS LSD 11 *

14. Effect of transition applications on green-up LSD 6 LSD 11 LSD 15 ** * * * ** * * *

15. Effect of dormant applications on henbit control. * LSD 11 NS

16. Effect of transition applications on henbit control * * LSD 15 NSLSD 9

17. Effect of dormant applications on common chickweed control * LSD 7 NS LSD 17 * *

18. Effect of transition applications on common chickweed control LSD 19 NS *

19. Effect of dormant applications on corn speedwell control * LSD 12 LSD 14 LSD 12 * * *

20. Effect of transition applications on corn speedwell control LSD 11 LSD 12 * * *

21. Effect of dormant applications on parsley- piert control * LSD 23 LSD 28 * * *

22. Effect of transition applications on parsley- piert control LSD 22 NSLSD 27 * *

23. Effect of dormant applications on white clover control LSD 13 LSD 23 LSD 30 * * * * * * * * *

24. Effect of transition applications on white clover control LSD 21 LSD 30LSD 20 * * * * * * ** *

25. Summary - Green-up l No effect for dormant applications. l Applied at 40% green-up, length of delay was: 4 Reward 0.25 lbs. - 14 days 4 Reward 0.25 + 0.25 lbs. - 21days 4 Reward 0.5 lbs. - 21 days 4 Roundup Pro - 42 days (58) 4 Finale - 34 days

26. Summary - Henbit l Reward & Finale > Roundup Pro 7 DAA l At 21 DAA all products equally effective

27. Summary - Common Chickweed l Applied to dormant turf, Reward > Roundup Pro & Finale at 7 DAA l No difference at 14 DAA l At 42 DAA, Reward 0.25 < Reward at 0.5, Roundup Pro & Finale l Applied during transition, Reward & Finale > Roundup Pro at 7 DAA only

28. Summary - Corn Speedwell l Applied to dormant turf, Reward and Finale > Roundup Pro at 7 DAA l Reward at 0.25 (40%) and 0.5 (47%) < Roundup Pro (95%) and Finale (83%) at 42 DAA l Applied during transition, Reward and Finale > Roundup Pro 14 DAA l Reward at 0.5 (98%) and Finale (100%) > Roundup Pro (85%) at 21 DAA

29. Summary - Parsley-piert l Applied to dormant turf, Reward and Finale > Roundup Pro at 7 DAA l Reward at 0.25 (53%) and 0.5 (60%) < Roundup Pro (97%) and Finale (98%) at 42 DAA l Applied during transition, Reward and Finale > Roundup Pro 14 DAA l No differences at 21 DAA

30. Summary - White Clover l Applied to dormant turf, Finale > Reward and Roundup Pro from 7 through 42 DAA l Applied during transition, Reward at 0.25 (48%) and 0.5 (67%) and Finale (72%) > Roundup Pro (23%) at 7 DAA l Finale (99%) > Reward (<50%) and Roundup Pro (67%) at 21 DAA

31. Methods l Established ‘Tifway’ bermudagrass l Plots 6.5 by 15.0 ft. l RCBD, 3 replications l Non-irrigated site

32. Methods l Dormant applications - February 18, 1997 l Transition applications - March 11, 1997 l CO 2 Backpack l 25 gpa

33. Application information