Pre-Emptive Eradication of Weedy Tropical Forages

Summary

Project B.NBP.0356 is the third phase of a twelve-year plant eradication program begun during 1999. The eradication program was instigated following concerns by government researchers and grazing industry representatives that some of the legumes evaluated in Beef Industry and state and federal plant evaluation programs may become significant weeds of north Australian grasslands. 
This project concerns four perennial legumes: 
Acacia angustissima syn. Acaciella angustissima, Aeschynomene brasiliana, Aeschynomene paniculata and Indigofera schimperi. 
All are well adapted to (various) large areas of northern Australia, prolific producers of long-lived seed and have either moderate (A. brasiliana) or low (other three species) palatability to livestock. Each can form dense stands, which often exclude companion plants, and are considered to have no, or very limited, production value. Acacia angustissima is currently a Class 1 Declared Weed in Queensland (along with other exotic Acacia) and A. paniculata has since been recognised as a national Sleeper Weed ie. a plant with the potential to have a significant impact on the economy should it become widely naturalised (Cunningham et al., 2003). The potential cost, in terms of lost beef production and costs of plant eradication of A. paniculata, alone, was estimated at over $350 M (Brinkley and Bomford, 2002). The other two legumes were rejected prior to release because of concerns of becoming non-productive contaminants of grazing lands.