Control of Florida Betony (Stachys floridana Shuttlew.) Emerging From Tubers

Abstract Derby (metolachlor + simazine), Pennant (metolachlor), and Princep (simazine) were tested at two sites to determine if they would provide control of Florida betony (Stachys floridana Shuttlew.) similar to Barricade (prodiamine). These herbicides were applied twice to containerized Florida betony grown from tubers—a preemergent application in September, 1992 and a postemergent application in November, 1992. Only Barricade (prodiamine) provided 14 weeks of good to excellent control at both sites. Pennant (metolachlor) at 5.4 kg ai/ha (4.8 lb ai/A) provided control equivalent to Barricade (prodiamine) 6 weeks after the initial application at one site and poorer but acceptable control at the other site. Derby (metolachlor + simazine) and Pennant (metolachlor) tended to reduce number of shoots and/or percent coverage compared to an untreated control but generally provided poor control. Princep (simazine) was ineffective.