Postemergence Broadleaf Weed Control with EH1587.

Field experiments were conducted in GA on buckhorn plantain, while research in TN was conducted on purple deadnettle and hairy bittercress. Herbicide treatments were initiated in GA on June 3, 2016 and TN on March 4, 2016. Treatments consisted of EH1587 (halauxifen-methyl + fluroxypyr + dicamba) (0.11 kg ai ha^-1, 0.21 kg ai ha^-1, and 0.31 kg ai ha^-1), 2,4-D + mecoprop + dicamba (Triplet) at 1.58 kg ai ha^-1, and 2,4-D + triclopyr + dicamba + pyraflufen-ethyl (4-Speed XT) at 1.4 kg ai ha^-1. EH1587 at 0.21 and 0.31 kg ai ha^-1 resulted in 57 to 60% purple deadnettle control 14 DAT, while applications at 0.11 kg ai ha^-1 only provided 47% control. Hairy bittercress control was 57 to 67% 14 DAT, regardless of EH1587 rate. Buckhorn plantain exhibited the highest level of control 14 DAT in response to applications of EH1587. Control was 79 to 89%, regardless of EH1587 rate. Higher control of buckhorn plantain in GA may be attributed to June application timings compared to applications made during March in TN. Triplet at 1.58 kg ai ha^-1 resulted in 33% purple deadnettle control, 53% hairy bittercress control, and 87% buckhorn plantain control 14 DAT, while 4-Speed XT resulted in 70% purple deadnettle control, 67% hairy bittercress control, and 92% buckhorn plantain control. Excellent broadleaf weed control (98 to 100%) was observed 28 and 35 DAT in response to EH1587, regardless of rate or broadleaf weed species. Control of hairy bittercress and buckhorn plantain with Triplet and 4-Speed XT was also excellent (97 to 100%) 28 and 35 DAT; however, control of purple deadnettle never exceeded 50% in response to Triplet. Purple deadnettle control in response to 4-Speed XT was 90% 28 DAT, but control declined to 77% 35 DAT as weeds began to recover from previous applications.