Harrington Seed Destructor: A New Nonchemical Weed Control Tool for Global Grain Crops
Michael Walsh, Ray Harrington & Stephen Powles (Crop Science)
Harvest weed seed control is a very important strategy in the integrated weed management (IWM) tool kit, and can be achieved by collecting chaff and processing it, or burning narrow windrows to reduce the weed seed burden. The Australian Herbicide Resistance Initiative’s (AHRI) latest paper, published in Crop Science, explores the previously unrealised opportunity of intercepting and destroying weed seeds that exit the grain harvester in the chaff fraction during harvest.
The Harrington Seed Destructor (HSD) provides over 90 per cent destruction of ryegrass, wild radish, wild oat, and brome grass seeds when utilised during the commercial harvest of wheat, barley and lupin crops.
Extensive field trials of the HSD system are currently being conducted across a broad range of agricultural systems. The HSD system aims to have a dramatic impact on agriculture not only in Australia, but around the globe.
Synergistic effects of atrazine and mesotrione on S and R wild radish (Raphanus raphanistrum) populations and the potential for overcoming resistance to triazine herbicides.
Michael Walsh, Karrie Stratford, Kent Stone & Stephen Powles (Weed Technology)
Earlier research by Sutton et al. (2002 Pest Management Science) and Hugie et al. (2008 Weed Science) established the powerful synergy achieved in a mixture of an HPPD and PS2 herbicide. This new AHRI research publication by Walsh et al. (2012 Weed Tech) confirms this synergy in the very economically damaging weed in Australia, wild radish. Sutton et al. (2002) also made the very important discovery that remarkably the HPPD/PS2 mixture is synergistic even on triazine resistant weed species. This was confirmed by Hugie et al. (2008) and also found in triazine resistant wild radish by Walsh et al. (2012). Commercially, HPPD plus PS2 herbicide mixtures are achieving synergy in various parts of the world. In Australia the wheat selective herbicide Velocity (Bayer) is a synergistic mixture of the HPPD herbicide pyrasulfatole and the PS2 herbicide bromoxynil.
Simulation modelling identifies polygenic basis of herbicide resistance in a weed population and predicts rapid evolution of herbicide resistance at low herbicide rates. Crop Protection 2012, Vol 40, 114-120
Manalil S, Renton M, Diggle A, Busi R, Powles SB (2012)
This paper utilises our PERTH resistance model (Renton et al 2011, Jnl. Theoretical Biology) and our field experiments on low herbicide dose (Manalil et al 2011, Weed Science) to model that low, below label, herbicide use rates can lead to rapid resistance evolution in cross pollinated Lolium. This modelling analysis adds to our increasing biological data of the adverse impact of low, below label, herbicide use rates in resistance evolution in genetically diverse, cross pollinated Lolium. We emphasise that this low dose resistance evolution is much more likely in obligate cross pollinated species than in self-pollinated species, as cross-pollinated species can easily and additively accumulate gene traits through cross-pollination. Of course, herbicide resistance evolution will occur at high herbicide use rates due to major effect genes but low, below label, herbicide use rates should be avoided as resistance evolution can be rapid and non-target site mechanisms such as enhanced metabolism are enriched which can endow resistance across dissimilar herbicide chemistries. | 
