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Publications (61)
Weeds are a significant threat to agricultural productivity and the environment. The increasing demand for sustainable weed control practices has driven innovative developments in alternative weed control technologies aimed at reducing the reliance on herbicides. The barrier to adoption of these technologies for selective in-crop use is availabilit...
Many advanced, image-based precision agricultural technologies for plant breeding, field crop research, and site-specific crop management hinge on the reliable detection and phenotyping of plants across highly variable morphological growth stages. Convolutional neural networks (CNNs) have shown promise for image-based plant phenotyping and weed rec...
For more than two decades, glyphosate has been relied on to control summer annual weeds in fallow systems in Australia’s northern grains region. With numerous cases of glyphosate resistance reported in weed species collected from this region, there are concerns about the future viability of this herbicide. A random seed collection survey of summer...
Site-specific weed control (SSWC) can provide considerable reductions in weed control costs and herbicide usage. Despite the promise of machine vision for SSWC systems and the importance of ground speed in weed control efficacy, there has been little investigation of the role of ground speed and camera characteristics on weed detection performance....
As highly adaptable plants, weeds have evolved numerous mechanisms to evade control in agroecosystems. For example, reliance on herbicides has resulted in widespread evolution of resistance in many species. Minimising weed adaptation is a major driver for integrated weed management strategies. Crop mimicry is a notable example of weed adaptation, w...
Weeds are a major impediment to crop and pasture production and profitability in Australian farming systems, and knowledge of their occurrence is vital in devising weed management solutions. This study examined the relationships between weed and crop species from observations made during surveys of randomly selected fields in grain and/or pasture p...
The past 50 years of advances in weed recognition technologies have poised site-specific weed control (SSWC) on the cusp of requisite performance for large-scale production systems. The technology offers improved management of diverse weed morphology over highly variable background environments. SSWC enables the use of non-selective weed control op...
Rigid ryegrass is a problematic weed species in winter crops and winter fallow; however, recently, this weed species has been observed in summer crops and fallow. These observations warrant the evaluation of different postemergence herbicides for its control. Outdoor pot studies were conducted during the spring-summer of 2021-22 to determine the pe...
Pressure is mounting on the agricultural sector to reduce reliance on herbicides for weed control leading to increased interest in the potential of cover crops to control weeds in summer fallows. The weed suppression ability of three summer cover crop species, buckwheat, millet and teff, was evaluated in field trials at two sites near Camden, NSW i...
Italian ryegrass is a major weed in winter cereals in the south-central United States (US). Harvest weed seed control (HWSC) tactics that aim to remove weed seed from crop fields are a potential avenue to reduce Italian ryegrass seedbank inputs. To this effect, a four-year, large-plot field study was conducted in College Station, Texas and Newport,...
The introduction of harvest weed seed control (HWSC) techniques and associated machinery has enabled the routine use of an alternative weed control technology at a novel weed control timing in global grain cropping fields. Driven by the significant threat of widespread populations of annual ryegrass (Lolium rigidum) with multiple-herbicide resistan...
The use of a fallow phase is an important tool for maximizing crop yield potential in moisture limited agricultural environments, with a focus on removing weeds to optimize fallow efficiency. Repeated whole field herbicide treatments to control low-density weed populations is expensive and wasteful. Site-specific herbicide applications to low-densi...
Wild radish is the most problematic broadleaf weed of Australian grain production. The propensity of wild radish to evolve resistance to herbicides has led to high frequencies of multiple herbicide resistant populations present in these grain production regions. The objective of this study was to evaluate the potential of mesotrione to selectively...
The use of a fallow phase is an important tool for maximizing yield potential in moisture limited environments. There is a focus on ensuring these phases are maintained weed-free as even low weed densities can be detrimental to fallow efficiency. Repeated whole field herbicide treatment to control low-density weed populations is expensive and waste...
Junglerice and feather fingergrass are major problematic weeds in the summer sorghum cropping areas of Australia. The objectives of this study were to investigate the growth and seed production of junglerice and feather fingergrass in crop-free (fallow) and under competition with sorghum planted in 50 cm and 100 cm row spacings at three sorghum pla...
Annual ryegrass (Lolium rigidum Gaud.), traditionally utilised as a pasture species, has become the most problematic and difficult-to-control weed across grain production regions in Australia. Annual ryegrass has been favoured by the adoption of conservation tillage systems due to its genetic diversity, prolific seed production, widespread dispersa...
Annual ryegrass (Lolium rigidum Gaud.), traditionally utilised as a pasture species, has become the most problematic and difficult-to-control weed across grain production regions in Australia. Annual ryegrass has been favoured by the adoption of conservation tillage systems due to its genetic diversity, prolific seed production, widespread dispersa...
Resistance to herbicides and the lack of new herbicide options have led researchers to explore alternate methods to manage weed populations in large-scale cropping systems. Crop competition is an effective weed management approach that can reduce the pressure on herbicides. Faba bean (Vicia faba L.) is an important winter legume crop in Australia....
Seed shattering refers to the natural shedding of seeds when they ripe, a phenomenon typically observed in wild and weedy plant species. The timing and extent of this phenomenon varies considerably among plant species. Seed shattering is primarily a genetically controlled trait; however, it is significantly influenced by environmental conditions, m...
Weeds are a significant threat to the agricultural productivity and the environment. The increasing demand for sustainable agriculture has driven innovations in accurate weed control technologies aimed at reducing the reliance on herbicides. With the great success of deep learning in various vision tasks, many promising image-based weed detection a...
The scale of herbicide resistance within a cropping region can be estimated and monitored using surveys of weed populations. The current approach to herbicide resistance surveys is time‐consuming, logistically challenging and costly. Here we review past and current approaches used in herbicide resistance surveys with the aims of (i) defining effect...
Increasing concern for the ongoing availability and efficacy of herbicides is driving interest in the development of alternative physical and thermal weed control methods. Fortunately, improvements in weed detection through advancements in computing hardware and deep learning algorithms are creating an opportunity to use novel weed control tools, s...
Sorghum halepense is a problematic weed with global occurrence in environmental, pasture, and warm-season cropping areas. High seed production, an ability to regrow from rhizome fragments, and herbicide resistance all contribute to difficulties in management. Infested crops have drastic yield losses, with secondary problems due to S. halepense func...
Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of weed seed containing chaff material into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the...
Robotic weed control through weed detection has become increasingly important due to mounting pressure on herbicides from resistance and the large impact of weeds on agricultural productivity. One of the major challenges is accurate classification of weed species for selective targeting in crop situations, whilst the existing studies are often cond...
Harvest weed seed control (HWSC) tactics are being investigated for herbicide resistance management by reducing the number of weed seeds entering the soil seedbank. Weed seed retention and the location where weed seeds exit the combine (chaff, straw, or grain) are factors influencing potential HWSC success. An experiment was conducted in 2014 and 2...
Narrow-windrow burning has been a successful form of harvest weed seed control in Australian cropping systems, but little is known about the efficacy of narrow-windrow burning on weed seeds infesting U.S. cropping systems. An experiment was conducted using a high-fire kiln that exposed various grass and broadleaf weed seeds to temperatures of 200,...
Australian conservation cropping systems are practiced on very large farms (~3000 ha) where herbicides are relied on for effective and timely weed control. In many fields though there are low weed densities (e.g. <1.0 plant 10 m ⁻² ) and whole field herbicide treatments are wasteful. For fallow weed control, commercially available weed detection sy...
Using energy requirements to compare the suitability of alternative methods for broadcast and site-specific weed control – CORRIGENDUM - Guy R. Y. Coleman, Amanda Stead, Marc P. Rigter, Zhe Xu, David Johnson, Graham M. Brooker, Salah Sukkarieh, Michael J. Walsh
Weed management is an essential element of successful crop production. In recent times, an exponential rise in human population and drastic changes in climate and production techniques have intensified the crop production systems and increased the weed infestations. The evolution of herbicide resistance in a large number of weed species across the...
In Australia, junglerice and feather fingergrass are problematic weeds in sorghum. The high seed production potential of these weeds increases their seedbank in the soil and makes weed control practices more difficult and expensive particularly when weeds have evolved resistance to herbicides. A study was conducted to evaluate the seed production a...
Downy brome ( Bromus tectorum ), feral rye ( Secale cereale ), and jointed goatgrass ( Aegilops cylindrica ) are problematic winter annual grasses in central Great Plains winter wheat production. Integrated control strategies are needed to manage winter annual grasses and reduce selection pressure exerted on these weed populations by the limited he...
The loss of herbicide options due to resistance and lack of herbicide discovery has delivered the realisation that herbicides are a finite resource and weed control alternatives are desperately needed. In Australian conservation cropping the only available alternatives suited to routine use are the recently introduced harvest weed seed control (HWS...
Junglerice [ Echinochloa colona (L.) Link] is a problematic weed in the northern grain region of Australia. Two pot experiments (Experiment 1 and Experiment 2) were conducted in a screen house to evaluate the growth and reproductive behavior of two biotypes (A, collected from a cotton ( Gossypium hirsutum L.)–fallow; B, collected from a fence near...
The widespread use of herbicides in cropping systems has led to the evolution of resistance in major weeds. The resultant loss of herbicide efficacy is compounded by a lack of new herbicide sites of action, driving demand for alternative weed control technologies. While there are many alternative methods for control, identifying the most appropriat...
Echinochloa colona and E. crus-galli are two important annual grass weeds distributed throughout the summer cropping regions of Australia. Both species are highly problematic weeds, responsible for yield losses of up to 50% in summer grain crops. The success of Echinochloa species as weeds is attributed to their rapid growth, prolific seed producti...
Brassica tournefortii is an important broadleaf weed of the winter season in the northern grain region of Australia. Knowledge of germination ecology of this weed would help in implementing effective weed control programs. A series of experiments were conducted to study the germination and dormancy behavior of four biotypes of B. tournefortii seeds...
African turnipweed ( Sisymbrium thellungii O. E.Schulz) is an emerging problematic broadleaf weed of the northern grain region of Australia. Laboratory experiments were conducted to evaluate the effects of temperature, light, salinity, pH, seed burial depth, and the amount of wheat crop residue on germination and emergence of two Australian S. thel...
Sisymbrium thellungii O. E. Schulz is an emerging problematic weed in the northern grain region of Australia. Several different biotypes exist in this region but not all biotypes exhibit the same growth and reproduction behavior. This might be due to local adaptation to the different agro-ecosystems, however, information on this aspect is limited....
Herbicide resistant weeds have been observed since the early years of synthetic herbicide development in the 1950's and 1960's. Since that time there has been a consistent increase in the number of herbicide resistance cases and the impact of herbicide resistant (HR) weeds. While the nature of crop production varies widely around the world, herbici...
In Australia, widespread evolution of multi-resistant weed populations has driven the development and adoption of harvest weed seed control (HWSC). However, due to incompatibility of commonly used HWSC systems with highly productive conservation cropping systems, better HWSC systems are in demand. This study aimed to evaluate the efficacy of the in...
The opportunity to target weed seeds during grain harvest was established many decades ago following the introduction of mechanical harvesting and the recognition of high weed seed retention levels at crop maturity; however, this opportunity remained largely neglected until more recently. The introduction and adoption of harvest weed seed control (...
Weed population simulations can be useful to predict the effects of alternative management practices on herbicide resistance (HR) evolution. Almost all previous simulations have ignored the possibility of within-field spatial structure in a weed population, instead making the implicit assumption of perfect dispersal and spatial homogeneity in popul...
Herbicide-resistant weeds affect every major cropping system today. Worldwide, there are 47 and 51 confirmed cases of herbicide-resistant weed populations in soybean [Glycine max (L.) Merr.] and rice (Oryza sativa L.) production systems, respectively. Alternatives to herbicides are necessary to help combat herbicide-resistant weeds. The integrated...
HWSC systems that target weed seed production during harvest have been in use in Australian crop production systems for over 30 years. Until recently, though, grower adoption of these systems has been relatively low. It is now apparent with the introduction of a range of new weed seed targeting systems that there is renewed grower interest in the u...
Harvest weed seed control (HWSC) systems have been developed to exploit the high proportions of seed retained at maturity by the annual weeds rigid ryegrass, wild radish, bromegrass, and wild oats. To evaluate the efficacy of HWSC systems on rigid ryegrass populations, three systems, the Harrington Seed Destructor (HSD), chaff carts, and narrow-win...
Mechanical weed seed destruction during harvest is an effective method of reducing viable weed seed inputs to the seedbank. The commercialized Integrated Harrington Seed Destructor (iHSD) was developed for destroying weed seeds contained in the chaff residue exiting the harvester. Considered state-of-the-art in harvest weed seed control (HWSC), wee...
Development of 2,4-D-resistant Brassica napus varieties is valuable for conservation tillage and post emergence control of broadleaf weeds. This research documents successful production and transfer of 2,4-D resistance from Raphanus raphanistrum (wild radish) into, Brassica napus via embryo rescue.
A large-plot field experiment was conducted at Keiser, AR from fall of 2010 through fall
of 2013 to understand to what extent soybean in-crop herbicide programs and postharvest
fall management practices impact Palmer amaranth population density and
seed production. The effect of postemergence-only (glyphosate-only) (POST) or
preemergence (PRE) foll...
Two of the most problematic Amaranthus species in soybean production today are waterhemp and Palmer amaranth. This study determined the percentage of waterhemp and Palmer amaranth seed that was retained by the weed at soybean maturity to assess the likelihood of using at- harvest weed seed control tactics for soil seedbank management. Palmer amaran...
With dryland cropping regions (<500 mm annual rainfall) comprising a substantial proportion (≈40 %) of the world’s land area the production from these regions defines global food supply. Therefore, it is imperative that weeds, the major constraint to dryland crop production, are controlled to reduce their impact on food supply. With soil moisture a...
Transgenic glyphosate-resistant canola was first commercially grown in Western Australia (WA) in 2010, providing an opportunity to obtain important baseline data regarding the level of glyphosate resistance in weeds following the exclusive use of glyphosate for in-crop weed control. In this study, two surveys (2010 and 2011) were conducted across t...
Seed production of annual weeds persisting through cropping phases replenishes/establishes viable seed banks from which these weeds will continue to interfere with crop production. Harvest weed seed control (HWSC) systems are now viewed as an effective means of interrupting this process by targeting mature weed seed, preventing seed bank inputs. Ho...
Phenoxy herbicides such as 2,4-dichlorophenoxy acetic acid (2,4-D) and 4-chloro-2-methylphenoxy acetic acid (MCPA) are selective herbicides used extensively in agriculture for weed control. Wild radish (Raphanus raphanistrum) is a problem weed across the globe and heavily infests crop fields in Australia. Phenoxy herbicides are used to selectively...
The phenoxy herbicides (e.g. 2,4-D and MCPA) are used widely in agriculture for the selective control of broadleaf weeds. In Western Australia, the reliance on phenoxy herbicides has resulted in the widespread evolution of phenoxy resistance in wild radish (Raphanus raphanistrum) populations. In this research the inheritance and mechanism of MCPA r...
The recently developed technique of burning narrow windrows to kill weed seeds has been extensively adopted by WA crop producers. A chute mounted to the rear of the grain harvester concentrates harvest residues including weed seed into narrow windrows in preparation for burning the following autumn. Preliminary kiln studies determined that temperat...