Commercial Safened ALS-herbicide Formulation Effects on ALS-sensitive Field Corn Hybrids

摘要

Research was conducted in 2014 and 2015 to determine if two common commercial acetolactate synthase (ALS) inhibitor herbicide formulations, that contain the crop safener isoxadifen, could be used on field corn (Zea mays L.) hybrids with reported ALS sensitivity. Two ALS-sensitive field corn hybrids (DEKALB DKC 62-08 and DKC 64-69) were treated 18 to 21 days after planting with nicosulfuron + rimsulfuron + isoxadifen or thiencarbazone + tem-botrione + isoxadifen at 1x and 2x labeled rates. No interactions were observed between herbicide treatment and field corn hybrid. When averaged over herbicide treatment, DKC 62-08 produced less aboveground biomass and was shorter in height than DKC 64-69. However, no difference in grain yield between hybrids wasobserved. When averaged over corn hybrid, only the 2x rate of tembotrione + thiencarbazone methyl + isoxadifen caused a significant reduction (19%) in aboveground biomass. Nicosulfuron + rimsulfuron + isoxadifen and tembotrione + thiencarbazone + isoxadifen, at both 1x and 2x rates, reduced plant height up to 3 inches 26 days after treatment (DAT). However, only the 2x rates of these safened herbicides caused significant height reductions 62 DAT. Both herbicide formulations at 1x and 2x labeled rates caused corn yield losses of 11 to 16 bu/acre. These data suggest that these particular commercial herbicide formulations can cause crop injury and subsequent yield loss when used on ALS-sensitive field corn hybrids.