Goosegrass (Eleusine indica) Control in Bermudagrass (Cynodonspp.) Turf by Diclofop

Abstract

Greenhouse and field experiments were performed to investigate diclofop rate and mowing height interactions on goosegrass control and ‘Tifgreen’ and ‘Tifdwarf’ bermudagrass tolerance. In greenhouse experiments, greatest goosegrass control was achieved with diclofop when plants were maintained at 1.3 cm. Increased diclofop rates were required to suppress goosegrass mowed higher than 1.3 cm or unmowed. Greater than 90% goosegrass control was achieved with the combination of 1.3-cm mowing height and 0.6 kg ai ha–1of diclofop. In field experiments, a minimum of 2 weeks was necessary for complete herbicidal activity. Diclofop at 1.1 kg ha–1provided >90% control of goosegrass mowed between 1.9 to 2.5 cm. The addition of nonionic surfactant (0.25% by vol) to diclofop did not influence control. The addition of metribuzin (0.1 kg ai ha–1) to diclofop resulted in initial increased control, but it was transient The addition of MSMA (2.2 kg ai ha–1) to diclofop reduced goosegrass control an average of 18% compared to diclofop treatments alone. Tifdwarf bermudagrass was more sensitive to diclofop compared to Tifgreen. Seven to 14 days were required for Tifdwarf to recover from initial injury. This injury, although significant, was acceptable for bermudagrass used for golf greens. Clipping weights following treatment were also less for Tifdwarf than Tifgreen.