Sequential herbicide treatments for large crabgrass (Digitaria sanguinalis) and goosegrass (Eleusine indica) control in bermudagrass (Cynodon dactylon) turf

Preemergence (PRE) and postemergence (POST) herbicides were sequentially applied to common bermudagrass over a two-year period to determine the lowest herbicide rates required to maintain acceptable large crabgrass and goosegrass control. Large crabgrass control was consistently higher in late August when MSMA at 2.2 kg ha-1was applied to plots previously treated with dithiopyr at 0.3 kg ha-1(99%) in 1991, and either pendimethalin at 1.1 kg ha-1(95%) or oxadiazon at 1.1 kg ha-1(94%) in 1992 than when either herbicide was applied alone (≤ 79%). Goosegrass control was also higher in late August when MSMA plus metribuzin at 2.0 + 0.14 kg ha-1was applied to plots treated with pendimethalin at 1.7 kg ha-1(71%) in 1991, with oxadiazon at ≤ 2.2 kg ha-1(≤ 89%) in 1992, and with dithiopyr at 0.4 kg ha-1(≤ 96%) both years than when the herbicides were applied alone. Diclofop at 1.1 kg ha-1applied alone as POST controlled ≥ 96% goosegrass throughout the two-year period.