Interaction of Flumioxazin with Dimethenamid or Metolachlor in Peanut (Arachis hypogaea L.)¹

Field studies were conducted in various peanut growing regions of Texas and Georgia to study peanut response to flumioxazin alone or in combination with dimethenamid or metolachlor. In south Texas during 1997, flumioxazin plus metolachlor resulted in greater than 45% peanut stunt, while flumioxazin plus dimethenamid caused ≤20% peanut stunt. This stunting was attributed to cool, wet growing conditions. Peanut yields in flumioxazin plus metolachlor-treated plots were reduced 58% from peanut in the non-treated check. In 1999 and 2000, flumioxazin plus dimethenamid or metolachlor resulted in 15% or greater peanut stunt, but stunting was not constant across weather conditions or locations. In west Texas and Georgia no peanut stunting with flumioxazin was noted. At the Levelland, TX location, flumioxazin at 0.07 kg/ha plus metolachlor at 1.1 kg/ha reduced peanut yield 32% when compared with the non-treated check; while at the Pearsall, TX location, metolachlor or dimethenamid at 1.1 kg/ha, flumioxazin at 0.07 kg/ha plus dimethenamid at 1.5 kg/ha, and flumioxazin at 0.1 kg/ha plus dimethenamid at 1.1 kg/ha reduced peanut yield 24 to 48% when compared with the non-treated check. No yield reduction was noted in Georgia.