Sign up to Wool.com and create your own personal wool hub.
Image courtesy of NSW Department Of Industries
Pasture dieback is a condition which predominantly affects sub-tropical sown grass species and some native grasses, resulting in significant pasture production losses over time and, subsequently, reduced carrying capacity.
Pasture dieback has been detected across a range of soil types, landscape locations and grass species in eastern Queensland and northern NSW. Pasture dieback is currently estimated to be affecting over 30,000 ha of land in Queensland.
What is pasture dieback?
Pasture dieback is defined as areas of grass dying without an obvious cause even in areas where rainfall has been recorded. Pasture dieback can be detected in pastures that are productive initially when sown or planted in suitable or fertile soils. However, the productivity and health of the plant will decline over time.
Pasture dieback has been identified in several grass species including bahia, buffel, creeping bluegrass, sabi grass, signal grass, para grass, paspalum, pangola, setaria, rhodes grass, panics and some native grasses such as black speargrass, forest bluegrass and golden beard grass.
It has been identified that the spread of pasture dieback is significantly higher in warmer, wetter months than in cooler months, making early identification and management crucial.
Initial signs of dieback include:
There are several indicators and symptoms of pasture dieback. Careful assessment of your pastures should be undertaken. Several of the more common symptoms include:
- Leaf discolouration (yellowing or reddening). This could be evident in patches, streaks or spots and leading to purple tones as the disease progresses.
- Root systems may appear in poor condition with dead areas or limited root systems.
- Affected pastures often turn grey and disintegrate when dead.
- Livestock may avoid grazing affected plants.
- Severe symptoms are often identified along fencelines and other areas of thick grass.
- Broadleaf weeds and legumes are concentrated in the areas affected by dieback.
What causes pasture dieback?
There are no firm answers to this question. However, it has been identified that pasture mealybugs may contribute to pasture dieback in these regions.
Other detrimental factors to plant health (including disease, fungi, insects and nutrition) are also being explored to understand more about what causes outbreaks.
How to minimise your risk:
If you have identified possible pasture dieback on your property it is essential that a farm plan be developed and put in place to reduce the possibility of the disease spreading. Regular monitoring of pasture and livestock grazing patterns is essential is highly recommended.
Developing a farm biosecurity plan that all staff and visitors abide by is essential. Reporting of any suspicious symptoms should be undertaken with the relevant reporting bodies.