Weed control and soil persistence studies with dimethenamid in maize.
Five field trials were conducted with maize on 2 soil types (sandy loam at Horotiu and clay loam at Hamilton) in 1988-92 to evaluate the efficacy, crop tolerance and residual activity of a new chloracetamide herbicide, dimethenamid (SAN 582H). Dimethenamid, applied pre-em. at 1.4 or 2 kg/ha, followed by a post-em. application of atrazine or dicamba, provided excellent control of annual summer grasses (mostly Digitaria sanguinalis, Panicum dichotomiflorum and Echinochloa crus-galli) and all broadleaved weed species present except Datura stramonium (i.e. Polygonum persicaria, Amaranthus powellii, Chenopodium album, Solanum nigrum, Rumex obtusifolius, Fumaria officinalis, Stachys arvensis and Spergula arvensis). The crop sustained no visual damage at any stage, and grain yields were not affected by the highest rate tested (72 kg). At probable field use rates, dimethenamid persisted in both soils at phytotoxic levels for 8-12 weeks.