Pasture dieback is a condition killing large areas of sown and native summer growing pasture in Queensland. The size of areas affected varies. It starts as small patches and can spread to affect large areas. In some cases whole farms have been affected. It is not limited by landscape or soil type. Livestock avoid grazing these areas making them unproductive (Figure 1).
Pasture dieback was first identified in Central Queensland and has now spread from Far North Queensland to the NSW border. Suspected pasture dieback was reported on a property in northern NSW in autumn 2019.
Pasture dieback affects summer growing grasses, both sown and native. It has not been reported in temperate grasses, with the exception of a single case of an annual ryegrass forage crop.
Sown species known to be affected include:
Other species known to be affected include:
There are potentially more grass species that could be affected.
Symptoms are most evident when pastures are actively growing during spring, summer and autumn. Symptoms of pasture dieback include:
Many of the dieback plant symptoms can be caused by a range of other factors. Including: mineral deficiency, drought, herbicide damage, water logging and nematodes. It is important to eliminate these before assuming dieback. However a combination of symptoms, including a rapid increase of the affected area following significant rainfall are good indicators of pasture dieback.
It appears to be the result of a complex interaction of multiple contributing factors, including environmental conditions. A couple of insects are currently also under investigation.
A number of techniques have been tried to control pasture dieback but no successful outcome has been resolved to date. Research is ongoing.
Movement of affected grass hay is one potential cause of spread. Source hay from reputable suppliers, especially pasture grass hay e.g. Rhodes grass.
Put in place best practice biosecurity actions to prevent entry, establishment and spread:
If you suspect symptoms of pasture dieback you can: