Bitou bush aerial spraying in New South Wales - what have we learned?
John TothA and Marion A. WinklerB
A Management of Environmental Weeds Pty Ltd, PO Box 330, Mona Vale, New South Wales 1660, Australia.
B Pest Management Unit, Department of Environment and Climate Change, PO Box 1967, Hurstville, New South Wales 1481, Australia.
Developing the aerial boom spraying methodology. Bitou bush (Chrysanthemoides monilifera subsp. rotundata (DC.) T.Norl.) is a significant environmental weed in coastal New South Wales (NSW). Control of extensive infestations of bitou bush within native vegetation can be undertaken using aerial herbicide application. Aerial spraying to control bitou bush proved to be a suitable control option following herbicide studies on native plant species which showed they were tolerant to the aerial application at very low rates during winter months (Toth et al. 1993). This technique was developed following ground based herbicide trials carried out in the late 1980s near Jervis Bay, NSW, in which six herbicides were initially trialled for the control of bitou bush. At the same time, a permit was granted to deliberately apply the same herbicides to seven native plant species, being Acacia longifolia subsp. sophorae (Labill.) Court, Banksia integrifolia L.f., Casuarina glauca Sieber ex Spreng., Leptospermum laevigatum (Gaertn.) F.Muell., Leucopogon parviflorus (Andrews) Lindl., Monotoca elliptica (Sm.) R.Br. and Lomandra longifolia Labill., to determine their response to off-target damage associated with bitou bush control. The results showed that only herbicides containing glyphosate or metsulfuron methyl as the only active ingredient were effective for controlling bitou bush (Toth et al. 1996). In addition, the effect of low rates of
glyphosate on the native species produced no measurable damage, and low rates of metsulfuron methyl resulted in only ephemeral damage to L. laevigatum and L. parviflorus. Hence these two herbicides proved sufficiently selective for bitou bush (Toth et al. 1993).
Plant Protection Quarterly (2008) 23 (1) 43-44.