Weed age affects chemical control of Conyza bonariensis in fallows

Boucher, Luke; Cook, Tony; Davidson, Bill; McLean, Andrew; Widderick, M.

doi:10.1016/j.cropro.2012.03.008

Cited by 21 publications

(15 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this research, the timing of the sequential applications was not explored. The first herbicide application always was applied when most of the plants were pre-to early-tillering.A recent study showed that 1 and 2 month old C. bonariensis plants were controlled better than 3 month old C. bonariensis plants with sequential herbicide applications (Walker et al 2012).The results of this study also suggest that it is likely that poorer control of E. colona would be achieved if the first herbicide application was delayed until most of the plants were mid-to late-tillering. In this situation, glyphosate would be less effective and more reliance would be placed on paraquat, particularly if applied to glyphosate-resistant plants.…”

Section: Sequential Applicationsupporting

confidence: 70%

“…A recent study showed that 1 and 2 month old C. bonariensis plants were controlled better than 3 month old C. bonariensis plants with sequential herbicide applications (Walker et al . ). The results of this study also suggest that it is likely that poorer control of E. colona would be achieved if the first herbicide application was delayed until most of the plants were mid‐ to late‐tillering.…”

Section: Discussionmentioning

confidence: 97%

See 1 more Smart Citation

Control by glyphosate and its alternatives of glyphosate‐susceptible and glyphosate‐resistant Echinochloa colona in the fallow phase of crop rotations in subtropical Australia

Widderick

Bell

Boucher

2013

Weed Biology and Management

View full text Add to dashboard Cite

Echinochloa colona is the most common grass weed of summer fallows in the grain‐cropping systems of the subtropical region of Australia. Glyphosate is the most commonly used herbicide for summer grass control in fallows in this region. The world's first population of glyphosate‐resistant E. colona was confirmed in Australia in 2007 and, since then, >70 populations have been confirmed to be resistant in the subtropical region. The efficacy of alternative herbicides on glyphosate‐susceptible populations was evaluated in three field experiments and on both glyphosate‐susceptible and glyphosate‐resistant populations in two pot experiments. The treatments were knockdown and pre‐emergence herbicides that were applied as a single application (alone or in a mixture) or as part of a sequential application to weeds at different growth stages. Glyphosate at 720 g ai ha−1 provided good control of small glyphosate‐susceptible plants (pre‐ to early tillering), but was not always effective on larger susceptible plants. Paraquat was effective and the most reliable when applied at 500 g ai ha−1 on small plants, irrespective of the glyphosate resistance status. The sequential application of glyphosate followed by paraquat provided 96–100% control across all experiments, irrespective of the growth stage, and the addition of metolachlor and metolachlor + atrazine to glyphosate or paraquat significantly reduced subsequent emergence. Herbicide treatments have been identified that provide excellent control of small E. colona plants, irrespective of their glyphosate resistance status. These tactics of knockdown herbicides, sequential applications and pre‐emergence herbicides should be incorporated into an integrated weed management strategy in order to greatly improve E. colona control, reduce seed production by the sprayed survivors and to minimize the risk of the further development of glyphosate resistance.

show abstract

Section: Sequential Applicationsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 97%

Control by glyphosate and its alternatives of glyphosate‐susceptible and glyphosate‐resistant Echinochloa colona in the fallow phase of crop rotations in subtropical Australia

Widderick

Bell

Boucher

2013

Weed Biology and Management

View full text Add to dashboard Cite

show abstract

“…The joint application of non‐chemical control (i.e. tillage, plant residue) before emergence with post‐emergence herbicides (amitrole+ammonium thiocyanate, glyphosate mixed with 2,4‐D amine plus picloram or three sequential application treatments of glyphosate mixtures followed by paraquat plus diquat) at the seedling stage (Bhowmik & Bekech, ; Wu et al ., ; Walker et al ., ) is an effective way to control the species. Control could be enhanced by carefully timing weed control measures at early growth stages.…”

Section: Discussionmentioning

confidence: 99%

A hydrothermal seedling emergence model for Conyza bonariensis

2013

View full text Add to dashboard Cite

Summary Conyza bonariensis is a South American native annual Asteraceae that has been introduced to the Mediterranean, where it behaves as a ruderal plant and a weed that is difficult to control in several crops. The development of predictive models can contribute to control measures at early growth stages, but currently there are no studies to predict seedling emergence of Conyza species. Our objectives were to develop and evaluate a model for predicting emergence response of C. bonariensis to the soil hydrothermal environment. A hydrothermal seed germination model was fitted to time course germination data from germination tests carried out at different constant temperatures and water potentials with the aim of establishing the hydrothermal parameters characterising C. bonariensis seed germination. The relationship between cumulative seedling emergence and cumulative hydrothermal time under field conditions was analysed using the Gompertz function. Model development was based on 2 years' data from a field experiment. Base temperature and base water potential for seed germination were estimated at 10.6°C and −0.70 ± 0.151 MPa, respectively. The emergence model showed a very good fit to the experimental data. According to this model, seedling emergence starts at 15 accumulated hydrothermal time (HTT) after sowing, and 50 and 95% emergence is completed at 53 HTT and 105 HTT, respectively. For model evaluation, independent field experiments were carried out in two localities. Cumulative seedling emergence was accurately predicted by the model. Results indicate that this model can be useful as a predictive tool contributing to effective control of C. bonariensis populations.

show abstract

“…Both direct and indirect effects of environmental conditions on weed response to herbicides have been the subject of extensive studies. The toxicity of foliar‐applied and soil‐applied herbicides has been examined with regard to the effects of ambient humidity, soil condition, irradiance, temperature regime and growth stage . For instance, the sensitivity of the response of annual weeds to particular herbicides may decrease or increase with age and/or increase with high temperatures (before and after treatment).…”

Section: Introductionmentioning

confidence: 99%