Keep An Eye Out For Pasture Dieback This Spring

Queensland graziers are being urged to keep an eye out for pasture dieback and consider management options.

Department of Agriculture and Fisheries (DAF) principal pasture agronomist Gavin Peck said the condition, which caused premature death of tropical and sub-tropical grasses, spread to new areas last year.

“Previously, pasture dieback generally affected high-yielding sown-grass pastures in regions with more than 600mm of average annual rainfall,” Mr Peck said.

“However, last summer it spread into western districts of southern, central and northern
Queensland where there was good summer rainfall.”

Mr Peck encouraged graziers to check early growth and condition now so they had time to manage towards assisting natural recovery, or to renovate or replace the pasture if required. 

“Initial symptoms of pasture dieback include leaf discolouration and unthrifty growth, before the pasture dies in patches.

“The dead patches are then colonised by broadleaf weeds or legumes—both of which are unaffected by pasture dieback.

“Some grass species recover and re-establish very well from the soil seed bank. Other moresusceptible species such as Kikuyu don’t seed readily and can struggle to recover without intervention.”

Mr Peck said graziers should check dieback-affected pastures for natural recovery and decide if they needed to replace the pasture.

“Paddocks that have surviving plants or good density of new grass seedlings can rapidly recover, especially with the use of broad-leaf herbicides to control weed competition.

“Severely affected pastures that do not have good grass seedling density or have had chronic multi-year pasture dieback can be renovated or replanted to legumes and more tolerant grasses.

“Given the early season break some areas have experienced, there is still time to kill the surviving grass (with chemical or cultivation) and start a fallow to establish a new pasture.”

DAF principal pasture agronomist Stuart Buck, who leads pasture dieback research in Queensland, said the condition was caused by pasture mealybug, a sap-sucking insect which was mostly spread by wind.

“Pasture dieback is likely to occur when pasture mealybugs are present in warm and wet conditions with a dense body of susceptible grass,” he said.

“Suspected pasture dieback can be reported through the Pasture Dieback App, which can be downloaded for free from the App Store or Google Play, or by calling DAF on 13 25 23.

“Reporting pasture dieback through our app takes less than 5 minutes.

“By uploading photos and describing the pasture species affected, you will help us better understand the spread of dieback.”

DAF has a range of dedicated tools and resources to help graziers identify and manage pasture dieback including the Queensland Pastures newsletter and pasture dieback workshops available on the FutureBeef website.

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Principal pasture agronomist Stuart Buck in dieback-affected pasture in Central Queensland. Photo credit: DAF

Bisset mealybugs

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