HERBICIDE PROGRAMS FOR RED RICE (ORYZA-SATIVA) CONTROL IN SOYBEAN (GLYCINE-MAX)

A study was conducted in 1994 and 1995 at two Mississippi locations to evaluate preplant incorporated (PPI) and preemergence (PRE) applicati ons of alachlor, clomazone, SAN 582, metolachlor, pendimethalin, and t rifluralin, and postemergence (POST) applications of AC 263,222 and im azethapyr alone or followed by clethodim late postemergence (LPOST) fo r red rice control in soybean. Applications of 110 g ai/ha clethodim i ncreased red rice control when following any earlier herbicide applica tion at one location that harbored a high natural infestation. In 1 yr at one location, red rice seedhead suppression from PPI and PRE herbi cide applications alone was greater than 95% due to high activity from herbicides and drought conditions during red rice seedhead developmen t. Early postemergence (EPOST) applications of 30 g ae/ha AC 263,222 s uppressed at least 95% of red rice seedheads, regardless of year, loca tion, or clethodim LPOST application. At one location, any treatment w here 110 g/ha clethodim followed an earlier herbicide application supp ressed red rice seedheads at least 95%. Compared to the nontreated con trol, only AC 263,222 injured soybean (30%) and reduced soybean yield (200 kg/ha).