Comparison of herbicides and times of spraying for the control of blackberry (Rubus fruticosus)

Abstract

Six herbicides were compared for the control of blackberry at ten sites in southern Victoria. When applied as a single spray, picloram and amitrole plus ammonium thiocyanate had a more persistent effect than 2,4,5-T, or the dimethylamine salt of polychlorobenzoic acid. Prometone had little effect. At the rates tested, mixtures of picloram plus amine 2,4,5-T were no more effective than ester 2,4,5-T. There was also no consistent improvement in the apparent kill of blackberry due to addition of amine 2,4-D to picloram when compared with picloram applied at the same rate. Seven times of application were compared. The best results were obtained during the summer, and the worst during the winter dormant period. Amitrole plus ammonium thiocyanate, and picloram were more effective than 2,4,5-T, particularly at times other than during the summer. The trials demonstrate the lack of persistence of herbicidal effects, and the need for more than one application.