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Development and application of rapid molecular assays for cotton pathology.
No full textSeveral endemic cotton diseases cause yield and economic losses in many Australian co on growing regions. Exotic diseases also present significant biosecurity risks. Traditional mycology methods can take days to weeks for a diagnosis and standard PCR methods for viral diseases can still take 1-2 days to complete. Rapid diagnostics such as new Loop-mediated isothermal amplification (LAMP) provide an opportunity to provide diagnostics within 1-2 hours from sampling symptomatic issue. This can provide a significant me saving in the lab and greatly reduce turnaround me to advise affected growers, leading to better management outcomes.
We have targeted pathogens that are either emerging, pose a biosecurity threat or may be difficult to distinguish from other diseases by symptoms alone. We have developed LAMP assays for endemic diseases co on bunchy top virus 1 and 2 (CBTV-1, -2), Eutypella sp., Fusarium Fov, and Ramularia pseudoglycines affecting co on, We have also developed diagnostics for the exotic co on leafroll dwarf virus (CLRDV) for incursion preparedness.
These LAMP assays are already proving useful for rapid turnaround diagnostics for CBT samples which increased in incidence in many areas in the 2022-23 season. We are beginning to apply the Eutypella LAMP to search for alternative hosts and pathogen reservoirs in the environment. The Ramularia LAMP was used to confirm infections in WA cotton, not reported in that region for several decades
Biological control of weeds in Australia: The last 120 years
Get PDFThe development of the field of biological control of weeds in Australia is described, from the first attempts in 1903 to the present day. The interest sparked by the obvious success of prickly pear program, apparent from 1930 to 1935, resulted in several programs during the next 20 years, followed by a decline in activity until the 1970s when activity increased enormously following the success of the skeleton weed program and the effective use of a plant pathogen for the first time. This momentum was maintained until the beginning of the present century with several successes and was marked by several important advances in genetic profiling, host-specificity testing, economic evaluation, conflict of interest resolution and the ecology of insect/plant interactions, including evaluation of the effectiveness of individual introductions. Biological control has proved to be a valuable and effective approach to weed management in Australia with 39% of all programs considered to produce complete or near-complete control, 30.5% partial control and an average benefit–cost ratio of 23:1. Funding for research has been variable with a decline from the late 1990s but with a significant increase again since 2020
Feral pig (Sus scrofa) activity and landscape feature revisitation across four sites in eastern Australia
No full textQuantifying feral pig movements and understanding the fine-scale ecological drivers of feral pig landscape use are important factors for optimising pest management programs. We tracked 59 GPS-collared feral pigs at four sites in eastern Australia between 2017 and 2021, for a mean of 375 ± 277 (s.d.) days. The mean number of successful GPS fixes was 15 577 ± 11 833 (s.d.) and these were recorded at 30-min intervals. We calculated mean hourly and daily distances travelled to determine feral pig activity and investigated the influence of sex, site, season and time of day on this activity. We also investigated the proximity of highly active sites to habitat covariates, along with intensity and frequency of site use. Male daily movement, 4.9 km (95% CI = 4.2, 5.6 km), was significantly greater than it was for females, 3.6 km (95% CI = 3.0, 4.1 km) and males maintained a high level of activity all night, while female activity was predominantly crepuscular. Study site was a significant determinant of daily movement, but season was not, across either sex or site. Highly-visited site selection was negatively associated with distance from creeks, dams, cultivation, open herbaceous vegetation and medium woody vegetation. Both medium woody vegetation and dam sites had the longest duration of use (3 and 2.7 h respectively) and the shortest time between visitations (14.5 and 13 h respectively). Quantifying feral pig activity and key habitat feature preference are important steps in improving management programs. Better prediction of feral pig movement and behaviour allows for more targeted placement of control tools, potentially increasing encounter rates
Assessment of Termite Damage in Cross-laminated Timber Sections Using Micro-computed Tomography and Vibration Analysis
Get PDFThe durability of engineered wood products (EWPs) is a parameter yet to be fully investigated and understood. This is specifically important for mass timber structures and cross-laminated timber (CLT) panels. The effect of termites and scale of damage on radiata pine sawn boards have been previously investigated. However, the effects of glue line and the layered structure of CLT exposed to termite feeding in the field in Australia have not been studied. A total of 420 CLT specimens with different exposed faces and layer arrangements were exposed to termite attack in the field. Microcomputer tomography and vibration analysis were used to assess sample conditions before and after 20 weeks exposure. The observed changes showed damage patterns within samples where a glue line and different growth ring patterns were present. The termites created continuous damage along the longitudinal cells through the length and width of the samples. The 3D data showed that the edge gap on the face of panels could potentially act as a pathway for termites entering the core or mid-layers of the panel. The vibration frequency values were lower for samples after the termite exposure. The vibration analysis results showed significant effects of sample direction exposed to termite attack, and percentage of mass loss had significant effects on internal friction and damping values determined. © 2023, North Carolina State University. All rights reserved
Reproductive performance of northern Australia beef herds. 7. Risk factors affecting mortality rates of pregnant cows
Get PDFContext: There are multiple reports of high annual cow mortality rates in northern Australia, but no reports clearly indicating the overall rates and the impact of primary risk factors.Aims: The research aimed to determine which measured region-, property-, management group- and animal-level risk factors are associated with missing pregnant females.Methods: Risk factors for the annual rate of pregnant-cow mortality were investigated in an epidemiological study using outcomes for 21 554 cows from 52 beef herds in 2009 and 2010 in four primary country types within the mostly-dry tropical north Australian environment. Modelling of 2001–2011 Australian beef-herd statistics was used to corroborate and further quantify findings.Key results: In the epidemiological study, the overall predicted annual mean incidence of missing pregnant cows, a surrogate for mortality, was 10.9%, including lost tags and unrecorded cow movement that were estimated to constitute up to 9% missing cows. Risk factors associated with higher pregnant-cow mortality were as follows: not having follow-up rainfall more than 30 days after the first wet-season storms (4 percentage point increase); <2 t/ha of available pasture biomass in the early dry season (2–6 percentage point increase); pasture dry-season biomass <2 t/ha interacting with less than moderate mid-dry-season body condition score (3–10 percentage point increase); and, calving between April and September (non-significant trend for a 1–2 percentage point increase). Feed-quality measures did not affect mortality rate. Population modelling of Australian beef herd statistics suggested an average annual cow mortality rate in the Northern Forest region of ~7% compared with 2% in more nutritionally endowed regions.Conclusions: The major risk factor for cow mortality is under-nutrition, related either to generally-low soil fertility, seasonally-dry conditions, or management that exposes animals to poor nutrition. Annual mortality of pregnant cows appears 6–9 percentage points higher in the low-fertility Northern Forest region than elsewhere.Implications: Beef cow mortality is a major business cost in northern Australia. The efficacy of targeted management to achieve high cow performance was demonstrated by losses in a third of studied businesses in the Northern Forest being kept to the same or lower levels as median loss in endowed regions
Movement behavior of swordfish provisions connectivity between the temperate and tropical southwest Pacific Ocean
Get PDFSwordfish (Xiphias gladius) are a widely distributed (45°N–45°S) large pelagic fish targeted by fisheries worldwide. Swordfish that occur at high latitudes tend to disproportionately be large adults, so their movements have implications for population dynamics and fisheries management. In the southwest Pacific, little is known about this subset of the stock and existing evidence suggests limited movement from the subtropics into cooler high latitude waters. Here, we capitalize on the recent emergence of a recreational swordfish fishery off temperate southeast Australia to characterize movements of swordfish caught in the fishery with pop-up satellite archival transmitting tags. Data were recovered from tags deployed for 56–250 days on 11 swordfish (50–350 kg) tagged between 38 and 43°S in the western Tasman Sea. Five swordfish entered the Coral Sea (< 30°S), with four reaching north to 11–24°S, up to 3275 km away from location of capture. Behavior modelling suggests these four individuals rapidly transited north until encountering 23–27 °C water, at which point they lingered in the area for several months, consistent with spawning-related partial migration. One migrating swordfish still carrying a tag after the spawning season returned to ~ 120 km of its release location, suggesting site fidelity. Movements toward the central south Pacific were confined to two individuals crossing 165°E. Swordfish predominantly underwent normal diel vertical migration, descending into the mesopelagic zone at dawn (median daytime depth 494.9 m, 95% CI 460.4–529.5 m). Light attenuation predicted daytime depth, with swordfish rising by up to 195 m in turbid water. At night, swordfish were deeper during the full moon, median night-time depth 45.8 m (37.8–55.5) m versus 18.0 m (14.9–21.8) m at new moon. Modelling fine-scale (10 min−1) swordfish depth revealed dynamic effects of moon phase varying predictably across time of night with implications for fisheries interactions. Studying highly migratory fishes near distribution limits allows characterization of the full range of movement phenotypes within a population, a key consideration for important fish stocks in changing oceans
Setting conservation priorities in multi-actor systems
Get PDFNature conservation is underresourced, requiring managers to prioritize where, when, and how to spend limited funds. Prioritization methods identify the subset of actions that provide the most benefit to an actor's objective. However, spending decisions by conservation actors are often misaligned with their objectives. Although this misalignment is frequently attributed to poor choices by the actors, we argue that it can also be a byproduct of working alongside other organizations. Using strategic analyses of multi-actor systems in conservation, we show how interactions among multiple conservation actors can create misalignment between the spending and objectives of individual actors and why current uncoordinated prioritizations lead to fewer conservation objectives achieved for individual actors. We draw three conclusions from our results. First, that misalignment is an unsuitable metric for evaluating spending, because it may be necessary to achieve actors’ objectives. Second, that current prioritization methods cannot identify optimal decisions (as they purport to do), because they do not incorporate other actors’ decisions. Third, that practical steps can be taken to move actors in the direction of coordination and thereby better achieve their conservation objectives
Impact of inoculum density of Fusarium oxysporum f. sp. zingiberi on symptomatic appearances and yield of ginger (Zingiber officinale Roscoe)
Get PDFGinger (Zingiber officinale Roscoe) is an important horticultural crop valued for its medicinal and culinary properties. Fusarium yellows, caused by the ascomycete fungus Fusarium oxysporum f. sp. zingiberi (Foz), is a devastating soil-borne disease of ginger. It has curtailed ginger production in Australia and around the world, leading to significant economic losses. An integrated approach is required to manage soil-borne diseases such as those caused by Foz. However, little is known about the influence of Foz inoculum on disease severity. This study aimed to establish a minimum threshold level of spores per gram of soil required for plant infection and to develop and evaluate a pot inoculation method for screening large numbers of plants in a controlled environment. To achieve this, the dominant Australian ginger cultivar Canton was inoculated with 101, 103, 105, 106 and 107 microconidia g−1 soil. The inoculum density was positively associated with leaf and stem yellows, and rhizome discolouration, and negatively associated with root length and rhizome weight. The lowest threshold required for plant infection was 101 microconidia g−1 soil, which may provide an important basis for outbreaks of Foz in the field. This finding adds significantly to our knowledge of the impact of soil health on ginger production, thereby contributing to the integrated management of Foz. When used at a high dose, this method can facilitate reliable and accurate screening of Foz-susceptible ginger genotypes in a controlled environment
Design, construction and management of flood refuge mounds
Get PDFAlthough widespread flood events are infrequent in Australia, when they occur, the resulting losses on the impacted communities are substantial and devastating.
Such an event occurred in north and north-west Queensland during the early months of 2019.
Record-breaking rain fell continuously for more than a week in the Southern Gulf Catchments and the Northern Lake Eyre Basin, causing extensive flooding locally and in the vast catchments downstream.
The North-west Queensland Monsoon event of 26 January – 9 February 2019: report of a landholder survey into impact and recovery, produced by the Department of Agriculture and Fisheries, estimates 457,000 cattle, 43,000 sheep, 710 horses, and over 3,000 goats died during this event with floodwaters impacting more than 11 million hectares of grazing land.
While not all those animals died from drowning, the lack of high ground to escape the floodwaters is thought to have contributed enormously. The information contained in this booklet describes how to make Flood Refuge Mounds (FRMs) to provide somewhere for stock to shelter in such a rare event
as that which occurred in 2019
Pangenome analysis provides insight into the evolution of the orange subfamily and a key gene for citric acid accumulation in citrus fruits
No full textThe orange subfamily (Aurantioideae) contains several Citrus species cultivated worldwide, such as sweet orange and lemon. The origin of Citrus species has long been debated and less is known about the Aurantioideae. Here, we compiled the genome sequences of 314 accessions, de novo assembled the genomes of 12 species and constructed a graph-based pangenome for Aurantioideae. Our analysis indicates that the ancient Indian Plate is the ancestral area for Citrus-related genera and that South Central China is the primary center of origin of the Citrus genus. We found substantial variations in the sequence and expression of the PH4 gene in Citrus relative to Citrus-related genera. Gene editing and biochemical experiments demonstrate a central role for PH4 in the accumulation of citric acid in citrus fruits. This study provides insights into the origin and evolution of the orange subfamily and a regulatory mechanism underpinning the evolution of fruit taste