•
SECTION 12 RESEARCH & EXTENSION This section brought to you in association with
R E S E A R C H
&
E X T E N S I O N
B Y
I N C I T E C
P I V O T
F E R T I L I S E R S
•
Burr breakthrough: Insights into Noogoora
A
ustralian scientists have developed a new biological control method for Noogoora burr, a troublesome weed with the ability to spread Verticillium. While a range of herbicides are available to control Noogoora burr, all can cause offtarget damage and are inappropriate for use in sensitive situations such as the riverine areas where the burr is often found. It is a serious threat to riverine ecosystems, habitats and native species, impacting 36 vegetation communities, including 11 Endangered Ecological Communities in NSW alone. The burr is also a known host of the pathogen that causes Verticillium wilt, and through this project its presence was confirmed in all Noogoora species.
The Australian Government in collaboration with NSW DPI, Murrumbidgee Irrigation, University of Queensland and CRDC supported the project Biological control and taxonomic advancements for management in the Noogoora burr complex. It was jointly led by NSW DPI’s Graham Charles and Dr Stephen Johnson, with NSW DPI cotton pathologist Dr Karen Kirkby.
Bio breakthrough Bioherbicides contain naturally occurring fungal pathogens specific to the target weed. Among their many benefits they are safe for use in sensitive environmental and production areas and are highly cost effective to develop and use when compared to traditional herbicides. But the pathogens typically in bioherbicides require free water from dew or rain for the fungi to develop and cause plant death. In dry areas this presents obvious limitations. “We have overcome this limitation, which we see globally, through the use of a complex emulsion,” Graham said. “Sourced through scientists from the University of Melbourne, and combining it with our pathogen, Alternaria zinniae, we were able to kill all Noogoora burr species and hybrid plants in our trials.” To get the technology into the field, the researchers will now partner with land managers in testing the product as it moves toward commercial viability. Future research could also extend the use of the emulsions to other pathogen/weed combinations to achieve bioherbicide control of other established weeds in primary production and environmental ecosystems, both in Australia and globally.
Clearer identification
CottonInfo Gwydir REO Janelle Montgomery collecting Noogoora burr samples for the breakthrough research. 152 — COTTON YEARBOOK 2019
Prior to this project, there were four species in the Noogoora burr complex recognised in Australia, but only a single species in the US where the burr came from, which raised questions for the researchers. “Clearly the identification of this weed was confused, and we were concerned this might have had implications for the control and disease-host status of the weed,” Graham said. “Initially, our research sought to better understand the taxonomy within the species complex since such uncertainty can constrain biological control efficacy.
