12903 research outputs found
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Improving bycatch reduction strategies and escape vents in Queensland crab fisheries
No full textThe Queensland Crab Fishery is an iconic fishery, which encompasses the harvest of mud crabs (Scylla serrata, the Giant Mud Crab, and Scylla olivacea, the Orange Mud Crab) and Blue Swimmer Crabs (Portunus armatus and Portunus pelagicus), predominately using baited crab pots of various designs. The Fishery has a limited entry commercial sector that requires a C1 symbol to catch these species of crabs, plus possession of appropriate quota to catch mud crabs on the Queensland East Coast (EC1), Queensland Gulf of Carpentaria (GC1) or Blue Swimmer Crabs anywhere in Queensland (BC1). The Fishery also has a significant recreational sector, that uses similar apparatus and does not require a licence, but does have in possession limits.
The current research investigated the performance of escape vents in crab pots targeting Giant Mud Crabs to determine if current Queensland fisheries regulations should be revised to provide better commercial outcomes (i.e., retention of legal mud crabs – male and 150 mm carapace width or greater), whilst minimising the bycatch of non-legal crabs, finfish and other bycatch species, such as water rats. The research focussed on the Giant Mud Crab as it comprises greater than 99% of the commercial harvest of mud crabs in Queensland.
The ongoing issue of marine turtle interactions with crabbing apparatus, including a recent increase of stranding reports, led to the research also collating available information about these interactions to support a risk mitigation strategy for the fishery’s interaction with protected marine turtle species.
Results are to be considered by management, Fisheries Queensland and the Crab Working Group as part of the Harvest Strategy arrangements for the Queensland Crab Fishery
Herbicide resistance in wild radish, brome and barley grass populations randomly collected in Australian surveys
No full textThe GRDC-funded random surveys conducted in Australia at harvest in 2020 reveal that herbicide resistant weed populations are common. However, the incidence of resistance varies significantly for weed species both within cropping regions and across Australia. Nationally, 130 wild radish, 382 brome grass and 251 barley grass populations were collected from cropping fields in WA, SA, Vic, Tas, NSW and QLD at harvest and were treated with a range of herbicides.
In wild radish, high levels of resistance to chlorsulfuron, imazamox+imazapyr (Intervix) and 2,4-D were detected. For the ALS-inhibiting herbicide chlorsulfuron, 71% of populations were resistant, with 47% of populations having cross resistance to the ALS herbicide mixture Intervix. Resistance to the synthetic auxin 2,4-D was observed in 37% of populations. Resistance to other herbicides was low, 15% of populations were resistant to diflufenican, only 3% of populations (all from WA) were resistant to atrazine, while developing resistance to pyrasulfotole+bromoxynil was observed and no resistance to glyphosate was detected. Herbicide resistant wild radish populations were more common in WA than in the other states.
Brome grass and barley grass were screened to quizalofop, clethodim, Intervix, sulfosulfuron and glyphosate. For brome grass, 29% of populations were classed as resistant to sulfosulfuron and a further 10% classed as developing resistance. Sulfosulfuron resistance was found in all states, although resistance to the other herbicides was low and varied between states. For barley grass (screened with paraquat in addition to the herbicides listed above), resistance was generally low for all herbicides across all states, although no resistance to glyphosate was detected. Continual monitoring of the distribution, incidence and frequency of herbicide resistance, and analysis of changes over time, will aid management decisions of farmers and agronomists
Reducing non-target damage to native emergent plants when managing aquatic weeds
No full textUrban wetland restoration requires planting native species that are consistent with the existing regional ecosystem. These young wetlands are particularly prone to weed invasion due to ongoing urban disturbances, implying herbicides may be used for maintenance purposes later. This study evaluated the aquatic herbicide sensitivity of common emergent macrophyte species in Queensland to inform planting choices in wetland restoration areas. Six native emergent plant species commonly used for restoration were selected: Baumea articulata, Boboschoenus caldwellii, Lepironia articulata, Eleocharis acuta, Philydrum lanuginosum and Cyperus exaltatus. They were grown in outdoor ponds located in Brisbane, Australia. Replicated mature plants of each species were sprayed with three aquatic herbicides at various doses up to their maximum label rate: flumioxazin (0, 25, 50, 105, 210 g ai/ha), glyphosate (0, 360, 720, 1440, 2160, 3240 g ai/ha) and florpyrauxifen-benzyl (0, 2.5, 5, 10, 15, 30 g ai/ha). Five months after treatment, all plants were harvested above substrate level and the dry mass of remaining live matter weighed. Glyphosate was the most destructive of the three herbicides tested as it significantly reduced the dry mass or completely removed 4 of the 6 species, while flumioxazin affected only 1 species and florpyrauxifen-benzyl did not affect any of them. E. acuta was sensitive to both glyphosate and flumioxazin. P. lanuginosum and C. exaltatus were the least sensitive species with no significant differences between controls and any of the three herbicides tested. At the time of writing, florpyrauxifen-benzyl is not yet registered for aquatic use in Australia. Plants that are more resistant to currently registered products can be selected for wetland restoration. At established sites, non-target damage can be predicted, and a suitable herbicide selected to reduce damage. Ongoing management of weeds that 'hide' among emergents, e.g. salvinia, can be effective without sacrificing natives
Dynamic spatial network simulation accounting for multiple ecological factors provides practical recommendations for biosecurity early detection and rapid response (EDRR) strategies
No full textBACKGROUND Globally the spread of invasive pests is being facilitated by increased human mobility and climate change. Simulation modelling can help assess biosecurity strategies for early detection and rapid response (EDRR), but has struggled to account for important factors in the invasion process, such as spatial and temporal variability in habitat suitability and connectivity; population dynamics; and multiple dispersal pathways. We developed a novel dynamic spatial network simulation approach based on spatial network theory that enables integration of a wider range of spatio-temporal factors than previous studies, calibrated it against extensive historical trapping data, and applied it to comprehensively analyse the EDRR strategy for Oriental fruit fly (Bactrocera dorsalis; OFF) in northern Australia. RESULTS Simulations indicated that the chance of OFF reaching the mainland in the next 20 years could be up to 20% under the current EDRR strategy, depending on how optimistic or pessimistic model assumptions are, and highlighted possible improvements to the EDRR strategy for further consideration. Simulations under optimistic assumptions indicate that transport via wind is most important in OFF reaching the mainland, but under pessimistic assumptions transport via people carrying infected fruit becomes more important. CONCLUSION Our new dynamic spatial network simulation approach can account for a wide range of spatio-temporal ecological factors to provide practical real-world recommendations. At a minimum, this approach only requires weather and population data, both of which are available globally from a variety of free and open sources, making it broadly applicable to assessing the EDRR strategies in place for different species in other locations. © 2024 Society of Chemical Industry
Epidemiology and Molecular Characterisation of Multidrug-Resistant Escherichia coli Isolated from Cow Milk
No full textAntimicrobial resistance (AMR) is a growing global concern and poses a significant threat to public health. The emergence of multidrug-resistant organisms, including Escherichia coli, also presents a risk of transmission to humans through the food chain, including milk. This study aimed to investigate the prevalence of E. coli in raw milk in the Chattogram metropolitan area (CMA) of Bangladesh and their phenotypic and genotypic antimicrobial resistance patterns. A total of 450 raw cow milk samples were collected from 18 farms within the CMA. The isolation and identification of E. coli were performed following standard bacteriological methods. Antimicrobial susceptibility testing (AST) was conducted using the Kirby–Bauer disc diffusion method. Molecular detection of E. coli and antimicrobial resistance genes was performed using the Polymerase Chain Reaction (PCR). This study found 134 (29.77%) milk samples that tested positive for E. coli. Antimicrobial susceptibility testing (AST) revealed the highest resistance rates (69.40%) to be for ampicillin, amoxicillin–clavulanic acid, cephalothin, and cephalexin, with the lowest resistance (21.64%) being for norfloxacin. A significant correlation (r = 1) was observed between ciprofloxacin and ceftazidime resistance among the antimicrobials tested. All E. coli isolates were classified as multidrug-resistant (MDR), being resistant to three or more antimicrobial classes, with a multiple resistance index >0.2. PCR amplification showed that the blaTEM gene had the highest prevalence (74.19%) among the ESBL and antimicrobial resistance genes tested. In contrast, the blaCMY-1 gene had a lower prevalence (6.45%) among the ESBL genes, while the tetD gene had the lowest prevalence (2.9%) among the resistance genes tested. Positive correlations were observed between antimicrobial resistance and the presence of these resistance genes. This study emphasises the high prevalence of MDR E. coli in raw cow milk and its significant potential impact on public health. It underscores the urgent need for strategic interventions to effectively manage and mitigate AMR in the Bangladeshi dairy sector, focusing on the prudent use of antimicrobials and implementing enhanced AMR surveillance
What do lettuce chlorosis virus, yambean mosaic virus and an unknown cogu virus have in common?
No full textDuring a 2021 disease survey of the beautiful Northern Peninsular Area (NPA) of Australia with some talented Northern Australian Quarantine strategy (NAQS) staff and Indigenous rangers, a sample of calopo (Calopogonium mucanoides) or wild ground nut, was taken. This unsuspecting calopo plant was hanging out on a wire fence in Umagico hiding its secrets within. But a couple of plant pathologists noticed its wrinkled leaves and mild mosaic pattern which alerted them to something being a bit suspicious. The leaves of the calopo were taken to a not so secrete lab in Brisbane where testing revealed a poty virus was hiding. A general poty PCR revealed it to be yambean mosaic virus (YBMV) not previously reported in Australia. Don’t worry, biosecurity was alerted! It could have all stopped there, but some pathologists need to know more (or don’t know when to stop), so the calopo RNA was sent for high throughput sequencing and then the true secrets were revealed. This plant had not just one new incursion, but three! A plant virologist dream (or is it a nightmare?). The findings and implications will be discussed
High Throughput Sequencing, Biosecurity and Policy in Plant Virus Diagnostics
No full textThe goal of the High Throughput Sequencing Working Group (HTSWG), a working group for the Subcommittee on Plant Health Diagnostics (SPHDs) is to facilitate the implementation of high throughput sequencing (HTS) standards and guidelines for plant health diagnostics in Australian jurisdictions and inclusion in National Diagnostic Protocols (NDPs). The uses of HTS in plant health diagnostics are many and varied. These cover anything from amplicon sequencing protocols to whole genome sequencing and even metagenomics. This means there is no one size fits all approach to assessing risk, meeting obligations under biosecurity at both state and federal levels and in developing new policy to ensure the results of HTS applications are reproducible, meaningful and relevant to our stakeholders. There is an increased risk of unintended consequences when complete sets of plant virus HTS data are uploaded to public databases owing to the fact they are often actually a plant metagenome, containing a wealth of other information which was never the original aim or target of the experiment. In this presentation, members of the working group hope to highlight the challenges with navigating the use of new methods in the plant virus diagnostics space where the policy and guidelines don’t always keep pace with new developments in technology. We discuss, and challenge everyone to consider these potential unintended or incidental findings that could be lurking in your data
Managing potyviruses in cucurbit crops by host resistance
No full textThree potyviruses: Papaya ringspot virus(PRSV), Watermelon mosaic virus (WMV) ,Zucchini yellow mosaic virus (ZYMV) (family Potyviridae: genus Potyvirus) cause major economic damage to cucurbit crops in all States. Zucchini and melon crops are particularly susceptible. PRSV dominates in Queensland and ZYMV in Western Australia. Insecticide applications have little effect on the rapid, non-persistent transmission of these viruses. Altering planting dates and crop hygiene can help but their influence is variable. Host resistance provides effective, economic control. Eighteen zucchini (Cucurbita pepo) varieties were recently assessed for virus resistance in a trial in south-east Queensland. All plants in two replicates were inoculated with PRSV at the cotyledon stage and the two replicates of the same varieties were not inoculated. Plants were assessed for symptom severity, total yields and yields of marketable fruit over five weeks with three harvests/ week. Four varieties were superior to the most widely grown virus tolerant variety in both inoculated and non-inoculated plots. Previous work has shown that varieties with good resistance to PRSV are also resistant ZYMV. Highly resistant zucchini varieties are commercially available and can largely prevent losses from potyvirus. Limitations identified in trial work include only average potential yields from some virus resistant varieties and mild leaf symptoms are not always well correlated with lack of fruit symptoms. Potyvirus resistant watermelon (Citrullus) and squash remain a challenge as no suitable material has been identified in greenhouse and field trials
Biology of Aproida balyi Pascoe, 1863 (Coleoptera: Chrysomelidae: Cassidinae: Aproidini) on its host plant, Eustrephus latifolius R. Br. ex Ker-Gawl (Asparagaceae) in Australia
No full textWithin the leaf-beetle subfamily Cassidinae (Coleoptera: Chrysomelidae), Aproida Pascoe, 1863 (Aproidini) from Australia has been considered a transitional genus between mining cassidines ('hispines') and exophagous cassidines ('tortoise beetles'). To illuminate this transition, a detailed study was conducted over one year of the biology of Aproida balyi Pascoe, 1863 on the host plant, Eustrephus latifolius R. Br. ex Ker-Gawl (Asparagaceae). Distribution maps of the host plant and three Aproida species are provided. The life cycle of A. balyi comprises single eggs in a foamy ootheca, three larval instars that feed openly, a pupa suspended from the larva III exuvia, and sexually dimorphic adults. The larva''s green color resembling the host and the narrow body fitted to the narrowed leaf blade allow them to camouflage. They possess a single long caudal process, unlike the paired processes of most other tortoise beetles. Fecal pellets are observed sometimes on this process, but accumulation is rare and lacks the permanent structure of exuvio-fecal shields that distinguishes the ten tribes of tortoise beetles. The larvae exhibit adhesive lobes on the abdominal sternites that appear to help their locomotion, a novel feature in Cassidinae. The pupa is suspended from the larva III exuviae and together they resemble the host''s pendant flower buds, suggesting mimicry. Males have the profemora and protibiae toothed. Both sexes can fly, unlike flightless Aproida cribrata Lea, 1929. These many morphological and behavioral findings contribute potential novel characters that underscore the aberrant nature of Aproidini within Cassidinae and point to another Australian evolutionary oddity
Temperatures above 30 degrees C decrease leaf growth in strawberry under global warming
No full textProductivity in strawberry is dependent on carbon assimilation in the leaves. The main scenarios for climate change include an increase in the concentration of CO2 in the atmosphere and an increase in temperature. This review examined the relationship between leaf growth and temperature in strawberry. Leaf growth follows a linear, sigmoid or Gaussian pattern over the season or is variable depending on the weather. There was a linear increase in leaf growth with temperatures below 26°C, and a linear decrease in growth with temperatures above 26°C. In other studies, the mean lower optimum for 90% of maximum growth was 18.3°?±?3.9°C, the median was 19.6°C, and the range was from 7.2° to 22.0°C (N?=?11). The mean higher optimum was 27.3°?±?3.6°C, the median was 27.4°C, and the range was from 21.1° to 33.5°C (N?=?12). Leaf growth was higher under 30°C and lower above 30°C. Limited studies suggest that elevated CO2 will not counteract the impact of high temperatures on growth. Climate change will increase leaf growth in cool areas and decrease growth in warm areas. The decrease in leaf growth in locations with temperatures above 30°C will contribute to lower yields under global warming