12903 research outputs found
Sort by
Comparing traditional and unmanned aerial vehicles (UAV) assessment methodologies in aquatic weed control research
No full textWeed control research involves pre and post treatment measurement of various plant attributes to determine treatment efficacy. Aquatic systems are challenging environments presenting specific risks, such as crocodiles, when conducting aquatic weed control trials in tropical Australia. The rapid emergence of technologies such as unmanned aerial vehicles (UAV’s) provides the opportunity to remotely collect data via the capture of high-definition imagery; therefore reducing risks whilst conducting research within aquatic systems. UAVs collect data in various parts of the electromagnetic spectrum including visible and infrared (which is particularly relevant to plants due to chlorophyll production). The use of drone-based assessment technology has the potential to augment, if not replace, traditional methods of determining herbicide efficacy. This study compared traditional ground-based (live stems counts and visual damage scores) collected data with remotely sensed UAV (Red Green Blue (RGB) and multispectral images for photogrammetry processing) data to determine whether UAVs could be used to assess the efficacy of field herbicide treatments on the ponded pasture species, Aleman grass (Echinochloa polystachya) (Kunth) Hitch.
There was a strong correlation between on-ground and aerial efficacy assessment results for some of the treatments. The correlation was consistent across the higher levels of treatment damage. The use of remotely captured imagery obtained via the UAV proved to be a reliable method for assessing treatment effects over time
Herbicide resistance in summer grasses and fleabanes – results from a national survey
No full textHerbicide resistance continues to be a major challenge in the effective control of weeds in Australian broadacre cropping. As part of a national survey, seeds of awnless barnyard grass (Echinochloa colona), feathertop Rhodes grass (Chloris virgata), sweet summer grass (Brachiaria eruciformis) and fleabane (Conyza bonariensis and C. sumatrensis) were collected from survivors in crop and fallows and screened for resistance against commonly used herbicides to quantify the extent of resistance. These summer growing weeds were predominantly found in the northern cropping region of Queensland and New South Wales.
All species were screened for resistance to glyphosate (Group 9) and paraquat or paraquat + diquat (Group 22). In addition, grass weeds were screened against haloxyfop (Group 1) and fleabane was screened against 2,4-D (Group 4). Treatments were applied at the upper label recommended rate and weed growth stage using a motorised spray cabinet. Populations were characterised for resistance according to percent survival where susceptible = 0%, developing resistance = 1 – 19% and resistant >19% survival.
Results have shown glyphosate resistance is common in these species with 100% of fleabanes, 99% of feathertop Rhodes grass, 58% of sweet summer grass and 48% of awnless barnyard grass populations resistant to glyphosate. Paraquat resistance was found in 8% of feathertop Rhodes grass populations and in 2 populations of tall fleabane. Favourably, no resistance has been found to Group 1 herbicides in summer grass weeds and 2,4-D in fleabane.
The discovery of Group 22 resistance in both feathertop Rhodes grass and tall fleabane is of particular concern as these herbicides are commonly used alone or as a second knock partner for double knock of these weeds. Alternative control tactics are required to manage these weeds.
Ongoing surveillance for herbicide resistance is required so the grains industry can make informed weed management decisions
Optimisation of a Stem-Implanted Herbicide Capsule System for Effective Management of Chinee Apple (Ziziphus mauritiana)
No full textThere has been a recent appreciation for “sustainability” and environmental stewardship within the agricultural industry driven by concerns of herbicide-resistance, unbalanced ecosystems, and food security. This has underscored the urgency for more novel solutions in weed management, with a particular focus on the reduced reliance of synthetic herbicides. In the last decade, a proprietary stem-implantation system has been developed for the encapsulated delivery of a fungal bioherbicide in parkinsonia (Parkinsonia aculeata). This technology has since expanded to the targeted, readily calibrated application of synthetic dry-formulations in several other woody weed species. More recently, a preliminary study investigated the compatibility of this technology for the management of Chinee apple (Ziziphus mauritiana Lam.) in rangeland environments. Although this research only “scratched the surface”, there were two synthetic formulations identified (330 mg/capsule metsulfuron-methyl and 1000 mg/capsule picloram) for further evaluation under field conditions. A replicated trial (n = 315) was established among a naturally-occurring population of Z. mauritiana near Mulgrave, northern Queensland to explore (i) the potential synergism of the two efficacious synthetic herbicides (i.e., combined formulation), and (ii) the placement of the capsules themselves. Each of three synthetic treatments (i.e., metsulfuron-methyl, picloram, and the combination herbicide) were applied at the very base of the stem and approximately one metre from ground-level. There was a significant effect (p 90% of treated plants) was observed among the encapsulated synthetic formulations delivered at the stem base. Theoretically, these compounds are more likely to be translocated downwards to the root system of the target species under the closest placement to ground-level. There was no significant differences (p >0.05) in the performance of the three synthetic formulations themselves at this optimised height of application
The tale of the Jatropha leaf-miner, Stomphastis thraustica in Australia
No full textImported into quarantine from Peru in late 2014 for the biological control of bellyache bush, Jatropha gossypiifolia, the path to the release in Australia of the Jatropha leaf-miner has been thwart with twists and turns. Initially thought to be a new species to science, in 2021 the identity of the insect was determined to be Stomphastis thraustica. Around the same time a leaf-miner found on bellyache bush in Australia was also identified as S. thraustica, though DNA analysis later demonstrated that it is a separate Stomphastis species. Given the time and effort already committed to the project by this point, the decision was made to proceed with the release of S. thraustica. Approval to field release the leaf miner was granted in September 2022. Field releases commenced in October 2022. To date, the leaf miner has been released at 33 sites across Queensland and the Northern Territory. Repeated releases are being made at these sites. The moth is believed to be an adept disperser and once it has established it will readily disperse to other infestations. Stomphastis species cannot be easily differentiated morphologically. The undescribed Stomphastis sp. already present in Australia is widespread, found at nearly all sites where S. thraustica has been released in Queensland, and the Northern Territory. Trials where the two species were forced to interbreed resulted in progeny only when Stomphastis sp. females were crossed with S. thraustica males and these progeny produced offspring. To confirm the establishment of S. thraustica and whether interbreeding occurs between the two species in the field, we will collect larval samples from release sites towards the end of the wet season in 2025 (≥ 2 years after initial releases) for DNA analysis
Effect of water stress on the growth and development of feathertop Rhodes grass (Chloris virgata)
No full textAnecdotal observations suggest that feathertop Rhodes grass (Chloris virgata) matures earlier when growing under water-stressed conditions. To investigate this claim, field capacities (FCs) aligning with severe (15, 25, 37.5% FC), moderate (50, 62.5, 75% FC) and no stress (100% FC) were imposed on plants in two consecutive growth cabinet experiments. The objectives of the study were to investigate if the growth and development parameters of feathertop, along with seed production and viability were impacted by FC. Under severe stress, feathertop tillered at 15% FC before dying, whereas plants at 25% FC matured and produced viable seed. Tiller production in plants grown at 37.5% FC and above were not significantly different and ranged from 18 to 22 tillers/plant before panicle initiation. The greatest dry weight biomass (8.20 g/plant) occurred with 75% FC, but this was not significantly different from biomass at 100% FC (7.44 g/plant). Plants grown under these conditions produced significantly heavier plants than at lower FCs (0.12 to 6.2 g/plant). Feathertop grown under severe stress took longer to mature; between 110 and 83 days (25% and 37.5% FC respectively) compared to between 58 and 77 days for plants grown at 50% FC and above. While plants grown at 25 and 37.5% FC remained vegetative for longer, once panicles were produced, they matured within 7 - 13 days, comparative to other FCs (10 - 13 days). Plants grown under severe stress produced between 1274 to 7351 seeds/plant (25% and 37.5% FC respectively) compared to seed production of 8891 seeds/plant (50% FC) and 15776 seeds/plant (75% FC). This research showed that soil water availability had a significant impact on the growth and development of feathertop Rhodes grass. In soils with a field capacity as low as 25% feathertop can survive and produce significant quantities of seed which return to the seed bank
Breeding new rootstocks for the Australian citrus industry
No full textRootstocks have shaped the history of world citrus production perhaps more than in any other food or fiber plant used by humans. For example, historically important issues such as phytophthora and Citrus tristeza virus (CTV) at one time appeared insurmountable but have been solved through new rootstocks that offered genetic resistance. There are few other crops where so many important commercial traits are influenced by the choice of rootstock. Within the Australian context, growers already have access to rootstocks with good tolerance to CTV and phytophthora, and there is an increasing availability of new options with salt tolerance and graft compatibility. The challenge for breeders is to develop new hybrids that capture all of these currently available features but offer additional benefits such as increased productivity, low vigour, improved fruit quality and resistance to newly emerging disease threats. This project sought to achieve this by generating hybrids from unique parents and then benchmarking these against recent releases from other international breeding programs and currently available commercial rootstocks. It used a strategy that involved multiple generations of crossing, and the production of bridging hybrids to overcome fertility barriers, followed by a sequence of large field trials with multi-year assessment of tree health, vigour, productivity and fruit quality. Information from these field trials was immediately used to guide the selection of parents in the annual hybridization activities, providing a feedback loop for constant improvement, and has resulted in a rich pipeline of germplasm to help secure the future of Australian citrus production. The conscious decision to detour from the very narrow genetic base of parents (sweet orange, mandarin, pummelo, trifoliate orange) universally used by other rootstock breeding programs is beginning to show benefits, and places the Australian rootstock breeding program in a strong position to deliver ongoing benefits to Australian growers
Australian Wheat Sustainability Framework: A Bottom-Up Model
No full textSustainability frameworks are essential for assessing the impact of technologies, practices, and policies on agricultural systems, incorporating biophysical, economic, and community values. In Australia, several frameworks, such as the Australian Agriculture Sustainability Framework (ASSF) and the Australian Grains Industry Sustainability Framework (GSF), exist, but they may not fully capture the diversity of grain-based systems or recognise the sustainable practices of growers. New tools and models are required to address these gaps. This paper presents a model that sets sustainability standards for wheat-based systems across various Australian regions. The model consists of six modules: Farm Management, Soil Health Management, Crop Management, Workplace Management, Biodiversity Management, and Capacity and Leadership. Each module uses parameters and a scoring system based on machine-learning models to evaluate sustainability at various geographical levels and within specific market categories. The model incorporates feedback from stakeholders in academia and industry. While initially designed for wheat production, this model can be applied to other crops leviable by the Grains Industry Research and Development Corporation (GRDC), including coarse grains, oil seeds, and pulses, extending its applicability and relevance. In conclusion, this model provides a strategy for improving sustainability within the Australian wheat industry while aligning with macro-level frameworks like ASSF. It offers mechanisms for growers to seek incentives from government, industry, and consumers for their practices, involving them in the sustainability process through a supportive approach. This model represents a significant step forward in the pursuit of sustainability in the Australian grain industry
Coleoptera of Brazil: what we knew then and what we know now. Insights from the Catálogo Taxonômico da Fauna do Brasil
No full textIn 2000, Cleide Costa published a paper presenting the state of knowledge of the Neotropical Coleopte-ra, with a focus on the Brazilian fauna. Twenty-four years later, thanks to the development of the Coleoptera section of the Taxonomic Catalog of the Brazilian Fauna (CTFB – Catálogo Taxonômico da Fauna do Brasil) through the collaboration of 100 coleopterists from all over the globe, we can build on Costa’s work and present an updated overview of the state of knowledge of the beetles from Brazil. There are currently 35,699 species in 4,958 genera and 116 families known to occur in the country, including representatives of all extant suborders and superfamilies. Our data show that the Brazilian beetle fauna is the richest on the planet, concentrating 9% of the world species diversity, with some estimates accounting to up to 15% of the global total. The most diverse family in numbers of genera is Cerambycidae (1,056 genera), while in number of species it is Chrysomelidae (6,079 species). Conotrachelus Dejean, 1835 (Curculionidae) is the most species-rich genus, with 570 species. The French entomologist Maurice Pic is the author who has contributed the most to the naming of species recorded from Brazil, with 1,794 valid names in 36 families, whereas the Brazilians Ubirajara R. Martins and Maria Helena M. Galileo are the only ones among the top-ten authors to have named species in the 21st century. Currently, approximately 144 new species of Brazilian beetles are described each year, and this average is projected to increase in the next decade to 180 species per year, or about one new Brazilian beetle every two days. © 2024 The Authors
Adaptation and plasticity of yield in hybrid and inbred sorghum
Get PDFLocal adaptation and genotype by environment (G×E) interactions affect the expression of phenotypes in crop species. An investigation on the interplay between adaptation and G×E on sorghum heterosis phenotypes is lacking. To address this question, a set of 112 diverse grain sorghum hybrids and their 22 inbred parents of local and exotic origins, representing the primary female and male heterotic groups, were tested in five contrasting sorghum growing environments across two years in Queensland, Australia. Plant height, days to flowering, seed yield, grain weight, and grain number were measured and used in the estimation of heterosis. Mid parent heterosis for yield ranged from -25 to 217% and was highly influenced by grain number. In contrast to observations in maize the magnitude of heterosis for yield was not associated with site mean. Striking differences were observed in heterosis in hybrids from locally developed inbred parents compared with hybrids that were developed from exotic inbred parents developed in other countries. Heterosis in the latter combination was higher on average across all the test environments for the majority of traits. We hypothesise maladaptive phenotypic plasticity in the exotic parents contributed to the observed differences in heterosis estimates. These data confirm that heterosis estimates in sorghum must be obtained and interpreted in relevant genetic and environmental contexts. Breeders in developing countries with low sorghum hybrid seed uptake will find these insights useful when selecting hybrids for broader adaptation, improving efficiency of their breeding programs. This article is protected by copyright. All rights reserve
Current status of insect resistance and Resistance Management Strategy
Get PDF• GRDC National Resistance Monitoring Project (2022-25)
• Resistance Management Strategy
• Trends in phosphine resistance
• Update on sulfuryl fluoride monitoring
• Update on grain protectant monitoring
• Key findings
• Industry interactions
• Ongoing research and future directio