Keep an eye out for pasture dieback
Now’s the perfect time for eastern Queensland graziers to check for pasture dieback—a condition that stunts growth and kills productive tropical grass pastures. And, to help with identification and proven management strategies, the Department of Agriculture and Fisheries has released three new videos.
Department of Agriculture and Fisheries principal pasture agronomist Stuart Buck said dieback typically affects high-yielding sown-grass pastures in regions that receive more than 600mm of average annual rainfall.
“Accurate identification of pasture dieback is not always straightforward during the initial stages because of similarities with other conditions,” Mr Buck said. “However, it can be easier to spot after rainfall, when surrounding pasture is greener.”
Pasture dieback is characterised by patches of otherwise healthy grasses exhibiting leaf discolouration, followed by unthrifty growth, premature death and colonisation by broadleaf plants such as weeds and legumes.
“Although pasture dieback starts in very small patches, it can spread quickly within one season,” he said.
Current research suggests there may be more than one agent causing pasture dieback.
“Research indicates the pasture mealy bug can cause pasture dieback, but a range of other pathogenic organisms, environmental factors and pasture management practices are also thought to play a role,” continued Mr Buck.
While pasture dieback is a complex issue there are a range of management activities land managers can do to assist their land to recover depending on the situation.
“Experience by graziers, and findings from research trials, demonstrate pastures can recover without re-sowing where new plants establish from the existing seedbank. Recovery can be sped up by conducting a forage budget so stocking rate is matched to pasture production and spelling the paddock if new pasture plants are establishing. Another useful practice is to spray out broad leaf weeds if present in dieback patches, where machinery is available and the landscape is suitable,” explained Mr Buck.
If legumes are not already present in the pasture then dieback can provide an opportunity to get these established.
“Annual and perennial legumes are not affected by pasture dieback and can provide high quality feed in the short and long-term. Species chosen will depend on soil type and climatic zone but perennial options such as desmanthus, sylos, bufferfly pea, siratro or leucaena can be good options,” said Mr Buck.
In the third video, Owen Price from Hillyvale, located in the Arcadia Valley, describes how pasture dieback has impacted their business, and how they are managing grazing to assist recovery. The Prices have been heavily impacted by pasture dieback but through advice and some experimentation have had success by re-sowing paddocks with desmanthus legume.
DAF is hosting two pasture dieback field days at and Moura and Middlemount in March, to showcase the findings of trials looking at management options for dieback. Trial plots across the two properties include spay, fertiliser and cultivation treatments, and grass and legume species selection.
Interested producers are invited to join the Pasture Dieback Industry Network.