FOUR weeds commonly found in various areas across Western Australia's grainbelt are being targeted by a collection of management packages which are being developed to control the major threats to agricultural production.
The Department of Primary Industries and Regional Development is undertaking the final year of a five-year research project to better understand and control matricaria, stinking love grass, marshmallow and Feathertop Rhodes grass, with co-investment from the Grains Research and Development Corporation.
As the project commences its final year, a series of Paddock Practices factsheets will be produced to assist landholders manage these weeds and minimise their impact on production and the environment.
Project leader Alex Douglas has been examining the weeds' biology to develop integrated weed control management strategies and said relatively little was known about the weeds and how they responded to herbicides and other typical control measures.
"While not currently widespread, these weeds can be a threat to crops and pastures, as they use soil nutrients and soil moisture required for crop establishment and yield optimisation," Ms Douglas said.
A fact sheet is being developed for matricaria, a winter growing weed with yellow ball flowers found across the eastern grainbelt.
Ms Douglas said while the weed was first noted in the eastern grainbelt in the 1960s, it has proliferated since the advent of reduced tillage practices in the 1990s, less livestock, bigger farms and a changing climate.
"This broadleaf weed has a pungent odour that smells like a cross between football socks and cat wee," she said.
"Sheep do not like to eat it so it is best controlled by a selective broadleaf herbicide, with field trials demonstrating that the timing of the herbicide treatments is crucial.
"The research has also found selective herbicides are best applied to small plants, while, in fallow situations, a knockdown is preferable when mixed with other herbicides to act as a spike."
Marshmallow is another winter weed, sometimes found in summer, which has proliferated through the grainbelt with the advent of minimum tillage practices.
"Marshmallow seeds are woody and as a result can survive in the soil for years until conditions are right for germination," Ms Douglas said.
"There are some residual herbicides that may extend the effective control period for marshmallow in specific crops."
Stinking love grass is another aromatic summer weed found in the eastern and northern grainbelt, Ms Douglas said.
"Stink grass, as it is sometimes shortened to, is not toxic and can be eaten by sheep when young as a management measure," she said.
"Grass selective herbicides are effective in controlling stinking lovegrass, as well as the knockdown herbicides, glyphosate and paraquat."
Feathertop Rhodes grass is a common summer weed that grows alongside many regional roadsides from Esperance to Geraldton.
"Seed survival studies have shown a high level of germination and low levels of dormancy," Ms Douglas said.
"Sheep love it, providing an effective non-chemical management option.
"Trials have shown some resistance to glyphosate and some selective herbicides."
As the project commences its final year, a series of Paddock Practices factsheets will be produced to assist landholders manage these weeds and minimise their impact on production and the environment.
