1. Cadre and Cotton “A Peanut Producer’s Dilemma” E. P. Prostko, A. S. Culpepper, T. L. Grey, C. W. Bednarz, and W. D. Duffie University of Georgia Tifton

2. Cadre in Peanuts F discovered (1981) F field tested (1989) F EUP’s (1993-95) F labeled (1996) F excellent control of nutsedge complex F G-E control of many other species 18 Month Cotton Rotation

3. Cotton in Georgia Planted Acres 1989-2001 Source: GASS

4. Cadre Injury Symptoms F stunting F shortened internodes F yellowish-orange leaf color (lime) F unpredictable

5. What do we know about Cadre?

6. Cadre Behavior in Environment F 120 day half life F upper 12-18” F degradation * microbial * photolysis?? Source: WSSA Herbicide Handbook

7. Factors that Promote Microbial Degradation of Pesticides F adequate moisture F warm soil temperatures (75-90 0 F) F favorable soil pH (> 5.5) F good aeration

8. Other Soil Properties that Influence IMI Persistence F higher OM soils F heavier soils (i.e. more clay) F low pH ( < 5.5) F Why? * Increased adsorption which reduces herbicide availability for microbial degradation * Increased adsorption which reduces herbicide availability for microbial degradation

9. Now you see it, now you don’t?

10. Seed Cotton Yield Response to Cadre Residues in North Carolina York et al., 2000 DES 119

11. How much Cadre does it take to cause injury?

12. Cotton Yield Response to PPI Applications of Cadre Averaged over 2 varieties (DP33B, SG501BG/RR) Tifton, GA 2000LSD 0.05 = 336 * *

13. Cotton Yield Response to PRE Applications of Cadre Averaged over 2 varieties (ST4892RR/BG, ST4691BG) Plains, GA 2000LSD 0.05 = 712 * * *

14. How much yield loss does Cadre carryover actually cause?

15. Cadre Carryover in Cotton Brooks County, GA - 2000 674 lbs 770 lbs 1540 lbs1348 lbs1220 lbs 738 lbs/A (lint yield) 1369 lbs/A 6/09/00

16. Are there variety differences?

17. Cotton Variety Response to Cadre at 8 PPB - 9 WAT Tifton, GA ef fg def fg def fg g

18. Cotton Variety Response to Cadre at 16 PPB - 9 WAT Tifton, GA a ab a abc ab a abc cde bcd a

19. Summary F cotton tolerant of 1/16-1/8X rates F carryover caused 46% yield loss F no significant variety differences * AP 6101 * AP 6101 * GA 161 (Phytogen) * GA 161 (Phytogen)

20. What can growers do? F follow 18 month restriction F reduced rates of Cadre? F banded applications F Cadre on irrigated fields only? F foliar fertilization? F optimum pH and nutrient levels F plant suspect fields last

21. University of Georgia Extension Weed Science (gaweed.com)