Virginia buttonweed is a difficult-to-control weed in southern turfgrass. Typically, auxin-type herbicides are considered to be the standard treatment for this species. Field experiments were conducted to compare the efficacy of flazasulfuron, a sulfonylurea herbicide, to pyridine herbicides on Virginia buttonweed. Treatments included single and sequential applications of flazasulfuron (0.05 or 0.08 kg ai/ha). The sequential applications were applied 3 and 6 wk after initial treatment (WAIT). Three applications of 0.05 and 0.08 kg/ha flazasulfuron controlled Virginia buttonweed greater than 93% at 10 WAIT. Both treatments were comparable to 0.6 kg ai/ha triclopyr 0.2 kg ai/ha clopyralid (80% control). These studies indicated that increased application of flazasulfuron increased Virginia buttonweed control regardless of application rates evaluated.

Nomenclature: Clopyralid, flazasulfuron, triclopyr, bermudagrass Cynodon dactylon (L.) Pers. ×Cynodon transvaalensis Burtt-Davy ‘Tifway 419’, Virginia buttonweed, Diodia virginiana L. DIQVI