herbicide resistance

This study provides examples showing that target-site resistance to POST herbicides and non-target-site resistance to PRE herbicides can be overcome by offering direct evidence across many L. rigidum populations screened. Evolved resistance to binary herbicide mixtures in individual plants may require the accumulation of multiple traits (at least two genetic traits) conferring resistance to each herbicide component applied at the maximum recommended dosage.

Glyphosate is often tank-mixed with auxinic herbicide 2,4-D for grass and broadleaf weed control. In this paper, the authors examined the possible interaction of 2,4-D and glyphosate in barnyard grass, Echinochloa colona. The results showed that 2,4-D antagonizes glyphosate remarkably in glyphosate resistant populations but only marginally in susceptible populations. This antagonism is related to reduced glyphosate uptake and (to a lesser extent) translocation. As 2,4-D has multiple, unpredictable effects on other herbicides, care must be taken when tank-mixing herbicides with 2,4-D.

This Special Issue of Plants comprises papers that describe the current status and future outlook of herbicide resistance research and development in weedy and domestic plants, with topics covering the full spectrum from resistance mechanisms to resistance management.

This study provides evidence that trait(s) enabling efficient trifluralin metabolism in Lolium rigidum are purged from the population under prosulfocarb recurrent selection.

It is speculated that survival to prosulfocarb via a lack of metabolic herbicide activation, and survival to trifluralin conferred by enhanced herbicide metabolism, are mutually exclusive.

In this work AHRI researcher Dr. Mechelle Owen surveyed and quantified weed seed infestation of the crop seed that farmers would be planting. In Australia, farmers save their own crop seed (wheat, barley, pulse crops, non-hyrbid canola) for planting in the subsequent growing season. Farmers produce their saved crop seed on low weed burden crop fields, so as to minimise weed seed contamination. This survey was done in 2015. This is the third AHRI survey, with the first conducted in 1998 (Powles & Cawthray 1999) and a larger second survey in 2009 (Michael, Owen & Powles 2010). In this third survey in 2015, Mechelle Owen surveyed 81 crop seed samples, each of 10 kg crop seed (wheat, barley, canola, lupins).

Resistance to the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) in wild radish (Raphanus raphanistrum) appears to be due to a complex, multifaceted mechanism possibly involving enhanced constitutive plant defence and alterations in auxin signalling. Based on a previous gene expression analysis highlighting the plasma membrane as being important for 2,4-D resistance, this study aimed to identify the components of the leaf plasma membrane proteome that contribute to resistance. Key results included: two receptor-like kinases of unknown function (L-type lectin domain-containing receptor kinase IV.1-like and At1g51820-like) and the ATP-binding cassette transporter ABCB19, an auxin efflux transporter, were identified as being associated with auxinic herbicide resistance.

Herbicide resistance in weeds is perhaps the most prominent research area within the discipline of weed science today. Incidence, management challenges, and the cost of multiple-resistant weed populations are continually increasing worldwide.

Six years of survey data taken from 184 paddocks spanning 14 million ha of land used for crop and pasture production in south-west western Australia were used to assess weed populations, herbicide resistance, integrated weed management (IWM) actions and herbicide use patterns in a dryland agricultural system. Key findings were that weed density within crops was low, with 72% of cropping paddocks containing fewer than 10 grass weeds/m2 at anthesis.

The evolution of herbicide resistance in weedy plants leads to various adaptation traits including flowering time and seed germination.

Cinmethylin is a new (old) herbicide being commercialised by BASF that is pre-emergent selective in wheat. Cinmethylin has been shown to be an inhibitor of acyl ACP thioesterase (Campe et al 2018).