Understanding of dieback in grasspastures across Queensland

Abstract

Pasture dieback is a condition currently causing death of a range of sown and native pastures across more than 200,000ha of Queensland’s productive grazing lands. Observations have occurred from the Atherton Tablelands in north Queensland, throughout eastern Queensland to the south-east corner of the state. Pastures affected by this condition are rendered unproductive, leading to significant financial stress for affected graziers.
The current dieback event was first observed around 2012 where buffel grass (Cenchrus ciliaris) and creeping bluegrass (Bothriochloa insculpta) were initially impacted across large areas of central Queensland and Burnett districts respectively. Now, almost every sown grass species found in Queensland has been affected. Prior to this current outbreak, pasture dieback was reported between 1993-4 mainly in buffel grass across central Queensland. Despite research studies at that time, the causal agent(s) were unable to be identified. Recent studies are still inconclusive but there are indications mealy bugs may have a role.
Dieback in pastures is a complex condition. Similar symptoms in grass-pastures across Queensland have been reported previously however confirming similarities has been problematic. Further, establishing consistent symptoms has also been difficult due to inconsistencies derived from the interaction of immediate and past seasonal conditions together with landscape and grazing management. Investigations into potential causes and management solutions have been conducted, or are underway, with mixed results. Continuing research is required to confirm the causal agent(s) and determine effective management options to restore productivity.