WEED SCIENCE Tropical Spiderwort (Commelina benghalensis L.) Control and Emergence Patterns in Preemergence Herbicide Systems

Tropical spiderwort is an exotic, invasive weed in the southern USA that has become one of the most troublesome cotton weeds in Georgia and Florida. Due to the continuous emergence pattern of tropical spiderwort, successful management will require a multi-component approach that includes an effective herbicide with soil residual activity. Field studies were conducted in Georgia and North Carolina to evaluate the effectiveness of several preemergence herbicides in suppressing tropical spiderwort emergence. The most effec-tive (≥80 % control) herbicides in 2002 at 6 wk after treatment (WAT) were clomazone at 0.42 and 1.05 kg ai/ha, fluometuron at 1.68 kg ai/ha