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Weeds research

Feathertop Rhodes grasss in a crop

The Agri-Science Queensland weed science team is at the cutting edge of research into Queensland cropping weed issues. Highly respected throughout the Australian weed scientist community, we conduct valuable research into:

  • best-practice weed management for Queensland agriculutre
  • weed ecology
  • non-chemical options for weed control.

The weed research program is based at the Leslie Research Facility, Toowoomba, with field research activities conducted throughout the northern grain belt and cotton region.  

Herbicide resistance

Several weed species have developed resistance to herbicides, and this is one of the most pressing issues in weed science worldwide. Our weed science team is at the forefront of analysis on this issue, researching resistance in Australian weed populations. Over the past decade, we have quantified risks associated with the development of herbicide resistance in weeds of the northern grain region, and have made recommendations for avoiding and managing weed populations resistant to important herbicides.

New tactics have been developed for managing herbicide resistant weeds, including the double-knock tactic. In addition, our research has produced a model of herbicide resistance evolution in grain and cotton farming systems of the northern grain region. Unlike previous models produced in other parts of Australia, the model enables simulation of a wide variety of weed species, agronomic practices and weed control tactics to help understand and explain the impact of agricultural decision-making on the rate of evolution of herbicide resistance.

Through a combination of investigation, modelling and information delivery, we are safeguarding Queensland cropping from potentially disastrous resistance to economically important herbicides. With the recent confirmation of several glyphosate-resistant common sowthistle populations in the northern region, we are now researching effective management options and conducting a field survey to identify how widespread this resistance is.

Weed ecology

A proper understanding of the ecology and population dynamics of important weed species is critical for us to provide useful recommendations on weed control to Queensland farmers. 

Several research projects are shedding light on aspects of the ecology of key weed species in Queensland, including:

  • wild oat
  • sowthistle
  • barnyard grass 
  • liverseed grass
  • feather-top Rhodes grass
  • windmill grass
  • fleabane

A survey of fleabane species distribution across the northern grain region was undertaken in 2006, in addition to experiments assessing fleabane populations for their herbicide tolerance.

Morphological variability in Queensland's barnyard grass populations was investigated in a PhD project, including whether there is a genetic basis for the differences observed in this weed.

Valuable information on factors influencing the germination, growth, and seed persistence of sowthistle was produced in another PhD project.
Experiments on the impact of crop sequences and agronomic practices on the seed-bank dynamics of key weeds began in 2009.

Non-chemical weed management 

We are actively pursuing and testing non-chemical management options for key weeds. In national collaborations, we are investigating the role of crop competition factors, harvest weed seed control and targeted tillage as new tactics for managing Queensland weeds.

Best-practice weed management

We have been particularly active in investigating the best management options for a range of problem weeds in Queensland grain and cotton farming systems. 

There have been several projects on the management of key weeds, both in-fallow and in-crop, for southern and central Queensland regions, particularly:

  • fleabane
  • sowthistle
  • barnyard grass
  • feather top Rhodes grass
  • sweet summer grass.

Our weed scientists have also made significant contributions to national projects as part of Cooperative Research Centres for Australian Weed Management, including the widely respected Integrated weed management manual and other publications promoting best-practice weed management.

As Queensland farming practices continue to change in response to various environmental, economic, and social factors, so the weed challenges faced by farmers will change. Our team is well placed, through a combination of approaches, collaborations and skills, to play a major role in assisting Queensland farmers adapt to change and improve profitability.

Further information