Publications

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.

Herbicides classified as synthetic auxins have been most commonly used to control broadleaf weeds in a variety of crops and in non-cropland areas since the first synthetic auxin herbicide (SAH), 2,4-D, was introduced to the market in the mid-1940s.

The incidence of weed species resistant to SAHs is relatively low considering their long-term global application with 30 broadleaf, five grass, and one grass-like weed species confirmed resistant to date.

An understanding of the context and mechanisms of SAH resistance evolution can inform management practices to sustain the longevity and utility of this important class of herbicides.

This research documented target site resistance in a Lolium population resistant to trifluralin and other dinitroaniline herbicides. Target site resistance in this particular population is endowed by changes at Arginine 243 of the alpha tubulin gene.

This research paper, “iHSD mill efficacy on the seeds of Australian cropping system weeds” by M Walsh, J Broster, S Powles, quantifies the efficacy of Harrington Seed Destructor (HSD) mills in destroying weed seed in the grain harvester chaff fraction.

PAM is a bio-economic model focussed on simulations of Palmer amaranth control practices that can be used to control this devastating weed in US crop production farming systems. PAM was produced at the University of Arkansas (M Bagavathiannan now at Texas A & M), particularly involving the program led by Jason Norsworthy.

This study was done with an Eleusine indica population originating from Malaysia that evolved resistance to glyphosate. This population was studied by AHRI PhD research student Adam Jalaludin. He established that this population exhibits extremely high-level glyphosate resistance (Jalaludin et al, 2014, Weed Research). Subsequent AHRI mechanistic studies found that this high-level glyphosate resistance is conferred by a double mutation within the EPSPS gene, known as TIPS, 102 Ile/106 Ser (Yu et al, 2015, Plant Physiology). Thus far, this is the only known case of this novel glyphosate resistance endowing double TIPS mutation evolving in weed plants under glyphosate selection.