Amitrole Translocation in Agropyron repens Increased by the Addition of Ammonium Thiocyanate.

The mechanism for the enhancement of amitrole activity on quackgrass (Agropyron repens) by the addition of ammonium thiocyanate was studied. Absorption and translocation of C(14)-amitrole after applications to foliage were determined by a direct count of the radioactivity in the wash solution and plant extracts. Regardless of the time of application, the addition of ammonium thiocyanate did not alter the amount of C(14)-amitrole absorbed. Ammonium thiocyanate (5000 parts per million) greatly increased the amount of carbon-14 translocated. This increase may account for the greater herbicidal effectiveness of the mixture of amitrole and ammonium thiocyanate.