Weeds of Significance to the Grazing Industries of Australia

Summary

119 weed species were listed as relevant to Australian grazing lands. This list includes annual and perennial grasses and forbs, shrubs, trees and aquatic plants. Together these weeds seriously affect a very large though undetermined proportion of Australian grazing lands in a variety of ways. Many are unpalatable or toxic to livestock. Others compete with more desirable pasture species and so reduce livestock carrying capacities. Some inhibit effective animal husbandry. Many of the species relevant to grazing industries are also significant environmental weeds.

Forty-eight species or species groups are listed being especially significant to Australian grazing lands. The species of greatest significance vary between bioclimatic zones. In the monsoon tropics the greatest need is to develop and promote systems approaches to the management of the unpalatable perennial grasses gamba grass, mission grass and giant rat's tail grass and the perennial forbs calotrope, sida and hyptis. In the tropical rangelands invasive exotic trees and shrubs are the highest priorities.

Research is most needed for parkinsonia, lantana and bellyache bush to cover critical aspects of their ecology and control, including biological control. Further work on biological control of mesquite and prickly acacia is also required. The rat's tail grasses and other unpalatable perennial grasses are also high priority and management strategies are required for noogoora burr in regions where current biological control measures are ineffective. Approaches to the sustainable management of proliferating native trees and shrubs are also important in the tropical rangelands.

High priorities in tropical and sub-tropical east coast grazing lands are the rat's tail grasses, lantana and creeping lantana. Parkinsonia is of medium priority in this zone, as are lippia, tobacco weed and sicklepod. In the temperate rangelands, African boxthorn is the highest priority exotic woody weed. Biological control may be a viable option for the management of this species. Two perennial forbs, lippia and mother-of-millions, should be given high priority, requiring effective management techniques and strategies. The annual forbs onion weed and saffron thistle also warrant research. In the cropping/pasture zone the greatest need is for the development of systems approaches to the management of a complex of weeds that includes annual grasses and annual and perennial forbs. Silverleaf nightshade and prairie ground cherry are high priorities at the species level.

The situation on the perennial pasture zone is similar to that in the cropping/pasture zone with a complex of annual and perennial grasses and forbs being high priority weeds and the greatest need being for systems approaches and improved management and extension material. African lovegrass, Chilean needlegrass, browntop bent, Parramatta grass, serrated tussock, silverleaf nightshade and prairie ground cherry are the most significant species. Measures to counter emerging weed problems should be high priority.