Efficiency of aerial techniques for long term control of serrated tussock (Nasella trichotoma)

Abstract

In three experiments near Rockley and Gunning, New South Wales, non-arable areas of serrated tussock (Nassella trichotoma) were aerially sprayed with 2,2-DPA in late summer and, in the following autumn, aerially fertilized and sown with pasture species. Measurements of tussock density and the botanical composition of the pastures were made for up to ten years after sowing. The experiments commenced in 1963, 1964 and 1966. About 90 per cent of the tussock plants were killed by applying the herbicide at 16.6 kg a.e. ha-l; higher rates effected little improvement. Aerially sown pastures further reduced tussock numbers and provided long term control. Best results were obtained on fertile soil and where tussock has not been retarded by burning. Of the pasture species sown Trifolium subterraneum and Phalaris tuberosa were the most effective for long term control.