MSMA for Weed Control in Wheat (Triticum Aestivum)

Postemergence applications of MSMA (monosodium methanearsonate) for weed control in spring wheat ( Triticum aestivum L.) were evaluated in the field, greenhouse, and controlled environmental chamber. MSMA controlled weeds better when applied to wheat at the four- to five-leaf stage than when applied at the two- to three-leaf stage. MSMA, tank mixed with barban (4-chloro-2-butynyl- m -chlorocarbanilate) or diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid}, controlled wild oat ( Avena fatua L.), green foxtail, [ Setaria viridis (L.) Beauv.] and broadleaf weeds better than did MSMA applied alone. Wild oat control with tank-mix applications of MSMA and difenzoquat (1,2-dimethyl-3,5-diphenyl-1 H -pyrazolium) was variable. Weed control with MSMA was enhanced by 30 C air temperatures, 90% relative humidity, and adequate soil moisture. A simulated rainfall of 0.5 mm within 0.5 h or 4 mm with 4 hr after application reduced wild oat control with MSMA.