Field and glasshouse trials on the control of bracken (Pteridium aquilinum) in Victoria

Abstract

Many herbicides have been tested against bracken (Pteridium aquilinum var. esculentum (Forst.) Kuhn.) growing in the glasshouse and in the field. Many of the systemic herbicides, and in particular MCPA, 4-CPA, 2,4,5-T, and amitrole, were very effective at rates between 2 and 10 lb an acre when sprayed on glasshouse-grown material. However, neither the compounds mentioned above nor any other compound yet tested was able to give a significant and permanent reduction when applied to bracken growing in the field. Various formulations of 4-CPA and amitrole, alone and in combination, gave highly significant reductions in fronds (as much as 80-90 per cent) for as long as six months after treatment, but by the end of twelve months, all treatments were indistinguishable from the controls. It is concluded that none of the systemic herbicides tested to date will eradicate field bracken with one treatment, and, although repeated sprayings would undoubtedly kill the plant, it is unlikely that such treatments would be economically sound.