Pasture team on a Western Queensland run talking about dieback

Pasture dieback was detected in new areas across western Queensland in the 2023/2024 summer, including the Mitchell, Charleville, Blackall and Jericho districts. Pasture dieback causes the death of productive sown grasses like Buffel grass, however other grasses can also be affected.

Dieback can be tricky to identify and manage, so Charleville Extension Officer Bec Brayley planned some information days to raise awareness ahead of the summer rainfall and pasture growth season. Bec said the information days at Mitchell, Augathella and Blackall were designed to show graziers what to look for and which management options can help.

“When dieback was first shown to me in Charleville in March 2024 I realised I had been driving past patches of dieback on roadsides all season and not known what it was. I figured most graziers would be the same as me, so thought we best have some information days so we all know what to look for and how to manage it.”

“We don’t have a lot of knowledge about dieback in this area and we really need to raise awareness, so I invited the DPI pasture dieback team out to share with us what they have learnt from managing dieback further East.”

The key messages about pasture dieback shared with attendees:

• Pasture dieback is easiest to identify in summer when grasses are actively growing – initial symptoms in affected buffel grass include reddening and yellowing of leaves, before plants become sick and die. Learn more about the symptoms of pasture dieback here.
• Plants that show symptoms will not always die – so don’t panic! Monitor the area multiple times throughout the season to determine if plants continue to be affected and die, or if they recover.
• Gayndah and American buffel are highly susceptible. Biloela buffel is more tolerant.
• Legumes are resistant.
• The most susceptible areas where symptoms are likely to be seen first are areas of thick, dense Gayndah or American buffel. Other grass species are susceptible, but Gayndah and American buffel are the most common sown grass in Western Qld. Dieback is more likely in areas that are not grazed often like laneways, dam squares and weaner paddocks so these should be closely monitored. Learn more about species susceptibility here.
• Pasture mealybugs cause dieback – they are small and white in colour. They feed by sucking on plant sap and are often found on the underside of leaves showing symptoms.
• Pasture mealybugs have natural predators including specific types of lady beetles, wasps and lacewings.
• Burning has limited impact on the mealybugs. There are no recommended chemical control options for pastures.
• Long term, the most sustainable control for pasture mealybugs is to have a pasture with tolerant grass species and resistant legumes. A summary of management options for pasture dieback can be found here.
• In country that can be cultivated, planting a forage crop to break the pest cycle can work well.

Many participants indicated pasture dieback has been in buffel grass at these locations in western Queensland for some time, potentially years. The area impacted is considered small at this stage but is likely to be increasing. Feedback from participants highlighted that their knowledge on dieback was low in these areas. Participants learned about the lifecycle of the mealy bug, how to identify dieback, pasture management and how important biosecurity is, in areas that are currently unaffected but susceptible.

As well as explaining the basics of Dieback identification and management, DPI Extension officer Ted Callanan highlighted the range of pastures that are susceptible to dieback. He emphasised “it’s not just limited to buffel grass, dieback has caused pasture collapse in kikuyu, Rhodes, green panic, bambatsi, signal, bisset bluegrass, some native grasses and more”.

Producers were shown the pasture dieback app and DPI Pastures Extension Officer Kylie Hopkins explained “when you log a location in the app the data comes directly to me. I am the one that evaluates the data, which we use to update our maps and prioritise our activities”

As pasture dieback is spreading into areas where it has not been seen before, producers were asked to be on the lookout for dieback particularly in Mitchell grass pastures. While no reported sightings of pasture dieback in Mitchell grass have occurred to date, any evidence of this occurring will be important to know so prompt investigations can take place.

These events are supported through the Queensland Pasture Resilience Program, a partnership between the Department of Primary Industries, Meat & Livestock Australia, and the Australian Government through the MLA Donor Company.