Blue lupin may have brightly coloured flowers, but its cerulean blossoms hold no appeal for many growers of grain lupin crops in Western Australia.
Also known as sandplain lupin, blue lupin (Lupinus cosentinii) has hard seeds which persist in the soil and germinate to compete with narrow-leaf and albus lupin crops - particularly in the Geraldton port zone.
Although still used for soil improvement and sheep feed in some areas where there are infertile deep sands, most western region growers now consider it a weed - and no registered herbicides will selectively control it in grain lupin crops.
The area of production of grain lupin crops averages 550,000 hectares per year in Australia and the crop is uniquely well suited to the deep, acid sandy soils that occur over large areas of WA - and which are particularly common in the state's northern grainbelt.
In the spotlight
Blue lupin is a particular focus of a new GRDC investment to review whether there are any possible chemical options for the management of broadleaf weeds of narrow-leaf and albus lupin.
GRDC crop protection manager - west, Georgia Megirian, says the research - being conducted this year by Independent Consultants Australia Network (ICAN) - would inform any potential future research, development and extension (RD&E) investments into broadleaf weed management in lupin.
"Chemical use in-crop and maximum residue levels (MRLs) are increasingly under scrutiny in our industry, so freedom to operate and market access are crucial considerations in any herbicide research," she says.
"This review is a critical step in seeking additional solutions for broadleaf weed control in grain lupin, as it will potentially identify particular chemistries that have registrant support and any data requirements necessary for regulatory approval of use.
"It will help to prevent the scenario where costly, and potentially unusable, bulk screenings of herbicides are undertaken in field trials.
"Rather, any necessary screenings in the field can be focussed and more likely to produce a scenario where growers can benefit from them."
Ms Megirian says chemical control options for blue lupin in grain lupin crops were not easy to identify due to the similarity between these species.
"The feasibility of other management strategies for blue lupin, including non-chemical options, are continuing to be explored," she says.
GRDC Research Code ICN2004-004CAX
More Information: Georgia Megirian, GRDC crop protection manager - west, 0439 575 900, firstname.lastname@example.org