Publications

Rigid ryegrass (Lolium rigidum Gaudin) is the most problematic weed in Australia, with evolved resistance to multiple herbicide sites of action. Selection pressure by cinmethylin (Group 30, a fatty acid thioesterase inhibitor) has been limited because few populations have been exposed to the herbicide since its introduction in 2019. In this study, we examined the sensitivity of L. rigidum populations to this new herbicide.

We have previously demonstrated that an aldo-keto reductase (AKR) from Echinochloa colona (EcAKR4-1) can metabolize glyphosate and confers glyphosate resistance. This study aims to investigate if the EcAKR4-1 orthologs from Lolium rigidum also play a role in glyphosate resistance in non-target-site based, glyphosate-resistant (R) L. rigidum populations from Western Australia.

Experiments were conducted to evaluate the single effect of soybean competition and its combined effect with a glyphosate field dose (1,080 g a.e. ha-1) on the growth and fitness of plants carrying glyphosate resistance endowing target site mutations.

We report here the first case of field resistance to HPPD-inhibiting herbicides in R. raphanistrum (wild radish), caused by 12 years of continuous reliance on that mode of action.

Cinmethylin, a pre-emergence herbicide inhibiting fatty acid thioesterase activity, has recently been introduced to Australian cereal cropping for the control of Lolium rigidum Gaud. (annual ryegrass). To date, there have been no confirmed cases of cinmethylin resistance identified in this species, but some populations exhibit reduced sensitivity to this herbicide.

This study evaluates the interaction among developing herbicide resistance, seed size and seed dormancy of ripgut brome, wild oat and hare barley collected from within intensively-managed fields (in-crop) in comparison with populations in surrounding ruderal (non-crop disturbed) areas with no history of exposure to herbicides within the Western Australian grainbelt.