Rice (Oryza sativa) response to clomazone plus bensulfuron and halosulfuron

A field study was conducted in 2002 and 2003 to evaluate the effect of clomazone at 448 g ai/ha plus bensulfuron at 10, 21, 31, and 42 g ai/ha or halosulfuron at 13, 26, 39, and 53 g ai/ha on rice. Herbicide treatments were impregnated onto urea fertilizer and applied at rooting (AR) in a water-seeded production system. Comparison treatments included clomazone AR followed by bensulfuron at 42 g/ha or halosulfuron at 53 g/ha POST. At 7 d after AR (DAAR), rice foliar bleaching decreased from 42% with a single application of clomazone to 23 to 30% with any rate of bensulfuron or halosulfuron impregnated with clomazone. Barnyardgrass and broadleaf signalgrass control did not decrease with the addition of bensulfuron or halosulfuron to clomazone. A single application of clomazone did not control rice flatsedge at 28 DAAR; however, rice flatsedge control was greater than 76% for all bensulfuron and halosulfuron treatments at 28 DAAR. There were no differences in rice yield among herbicide treatments.