2018

Identity and Activity of 2,4-Dichlorophenoxyacetic Acid Metabolites in Wild Radish (Raphanus raphanistrum)

Synthetic auxin herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D), are widely used for selective control of broadleaf weeds in cereals and transgenic crops.

Download PDF

Effect of crop residues on interception and activity of prosulfocarb, pyroxasulfone, and trifluralin

Crop residue retention on the soil surface in the no-tillage system can intercept pre-emergent herbicides and reduce their efficacy. Three experiments were conducted to investigate the effect of crop residue amount (0, 1, 2 and 4 t ha–1), moisture (wet versus dry), type (wheat, barley, canola, chickpea and lupin) and age (fresh or aged for one year) on the interception and subsequent leaching of prosulfocarb, pyroxasulfone, and trifluralin from the residue into soil.

Download PDF

Influence of Crop Competition and Harvest Weed Seed Control on Rigid Ryegrass (Lolium rigidum) Seed Retention Height in Wheat Crop Canopies

The obvious evolutionary reality is that persistent use of harvest weed seed control (HWSC) is a selection pressure for any mechanisms enabling L. rigidum seed to avoid HWSC. For example, seed shatters before grain harvest or a greater percentage of retained seed at a height below that at which the crop is cut in the harvesting operation.

Download PDF

2,4-D and dicamba resistance mechanisms in wild radish: subtle, complex and population specific?

An overall finding of this study of auxinic herbicide resistance, at least in Raphanus R populations, is that conclusions on mechanisms cannot be made from studying just a few R populations. There are very clear differences between and within resistant populations. This research is ongoing in an attempt to reveal the important mechanisms that can endow resistance to 2,4-D and dicamba in plants.

Download PDF

Glyphosate Resistance in Tridax procumbens via a Novel EPSPS Thr- 102-Ser Substitution

In this research, it was first established that Tridax, a global tropical weed species, evolved glyphosate resistance in the Ord River irrigation area in north-western Western Australia. This is the first report of glyphosate resistance in Tridax. The mechanism of glyphosate resistance was studied.  Various possible resistance mechanisms were NOT responsible for resistance (EPSPS gene amplification, different glyphosate uptake or translocation). In this glyphosate-resistant Tridax population, the glyphosate resistance mechanism is a mutation in the EPSPS gene causing substitution at amino acid 102 (Thr-102-Ser). 

Download PDF

Non-target-site glyphosate resistance in Echinochloa colona from WA

Earlier papers by Gaines et al 2012 Weed Technology and Goh et al 2016 Pest Management Science, documented a glyphosate resistance Echinochloa population from the irrigated north-west Ord River irrigation region of Western Australia. AHRI PhD student Sou Sheng Goh studied this population for his PhD research. Among other studies, Goh completed excellent work to identify the mechanistic basis of glyphosate resistance in this Echinochloa population. Goh examined for but did not find EPSPS resistance gene mutations and/or EPSPS gene amplification. Thus Goh established that glyphosate resistance in this particular resistant biotype is NON-target site based. 

Download PDF

Pyroxasulfone resistance in Lolium rigidum is metabolism-based

This study shows that the resistance mechanism endowing pyroxasulfone resistance in this Lolium rigidum population is enhanced rates of pyroxasulfone metabolism. This enhanced rate of pyroxasulfone metabolism is associated with over-expression of two glutathione transferases. Thus, the resistance mechanism in this Lolium population of enhanced rates of pyroxasulfone metabolism suggests GST-catalysed increased rates of glutathione conjugation. More work is required for definitive evidence of specific responsible GSTs.

Download PDF

2,4-D and dicamba resistance mechanisms in wild radish: subtle, complex and population specific?

Danica Goggin

In an Australian Research Council funded Linkage project with Nufarm as the industry partner, AHRI researcher Danica Goggin combined a transcriptomic and biochemical approach to investigate the diversity of 2,4-D resistance mechanisms in 11 resistant populations of wild radish. All of these wild radish populations had a relatively high level of resistance to 2,4-D and dicamba, although there were differences between populations in the level of resistance.

Download PDF

Modeling the Impact of Harvest Weed Seed Control on Herbicide-Resistance Evolution

In this modeling work, Gayle Somerville evaluated the value of HWSC in minimising the rate of herbicide resistance evolution. The modeling clearly showed the benefit of HWSC in minimising resistance evolution. There is a real benefit in having the diversity tactic of the non-chemical HWSC in minimising the rate of resistance evolution. HWSC reduces weed numbers over time and helps achieve greater sustainability and longevity of important herbicide resources.

Download PDF

iHSD Mill Efficacy on the Seeds of Australian Cropping System Weeds

The term “harvest weed seed control” is used to describe several techniques (narrow windrows burnt, chaff carts, grain harvest chaff & straw baling, chaff-lines, chaff decks, HSD) that can be used at grain harvest in Australian grain cropping.  These techniques target destruction of weed seed harvested during the grain harvest.  The majority of the weed seed processed by the grain harvester usually exits in the chaff fraction. This work quantified the efficacy of the iHSD to destroy the seed of a range of crop weeds.

Download PDF

1 2

Get access to short and sharp insights into the world of more crop, fewer weeds with AHRI Insight.
Subscribe Now