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Current Status and Future Prospects of Contact Insecticides in Stored-Product Protection
No full textHistorically, contact insecticides have played a major role in managing pests in postharvest stored commodities. Despite the availability of significant literature published over the past three decades, the current status and potential future use of contact insecticides are not known. In this review we synthesize the literature to identify reasons for the ongoing decline in the use of contact insecticides in postharvest commodity protection, and outline the challenges and opportunities for their future use by the grain industry. Development of resistance in major stored-product insect pests to conventional pesticides and the stricter regulatory requirements driven by consumer sensitivity to pesticide residues on food are discussed in detail to explain the limitations to their current use. We also highlight the strategic integration of currently available contact insecticides into a fumigation-dominated pest management program. We conclude by proposing several research aspects that may prompt their continued use by the grain industry in the near future
Impacts of grazing management on biocrust microbiomes and their potential to input and cycle nutrients
No full textBiological soil crusts (biocrusts) are key components of dryland ecosystems, hosting diverse microbial communities that mediate ecosystem services. In grazed drylands, biocrusts help replenish nitrogen (N) incorporated into livestock; hence, it is important to understand how grazing management affects them. We used shotgun metagenomics to investigate the impacts of four grazing treatments – (1) non-grazed, (2) moderately stocked, (3) heavily stocked, and (4) moderately stocked with wet season rotational spelling (cattle removed every 3–4 years) – on the diversity and potential function of biocrust bacterial communities in two distinct land types (Ironbark and Box) within a northeast Australian semi-arid tropical savanna. Grazing significantly influenced taxonomic and functional gene profiles and reduced biocrust cover, although these effects differed between land types. In Ironbark, the effect of moderate stocking on community composition was intermediate between the non-grazed control and heavy stocking treatments, while in Box it more closely resembled the heavy stocking rate. Rotational spelling had negligible impacts on biocrust bacterial diversity and potential function but mitigated the negative impacts of grazing on biocrust cover, particularly in Box. At the genetic level, we identified diverse bacterial lineages potentially capable of N fixation and similar relative frequencies of N fixing genes between grazing treatments. Hence, to maximise N inputs, rangeland managers should reduce biocrust losses. Our findings indicate that the frequency and duration of rotational spelling should be explored as a promising approach to mitigate the negative impacts of grazing on biocrust cover to maximize the capacity of biocrusts to replenish N
A deep learning model to time-profile plant nutrient uptake in a growth accelerator
No full textSynchrony between nutrient supply and plant demand is a key performance indicator of enhanced efficiency fertilisers (EEF’s). This study sought to develop a high throughput technique for rapid, non-destructive plant biomass measurements. In three experiments, a 3D camera mounted on a robotic gantry scanned pots weekly. A deep learning neural network (RandLA-net) was trained with colour point cloud (PCD) data to isolate a single central plant from partly overlapping adjacent plants and infrastructure (overall testing accuracy of 0.93 and mean intersection over union, IOU, of 0.90). Segmented voxels counts were strongly related to above ground dry matter (R2 = 0.87; P < 2.2e-16), and key statistics related to nutrient synchrony, for example inflection point of the logistic curve, were successfully measured. The high-throughput technique allowed rapid evaluation of fertiliser treatment performance and relative nutrient synchrony over time. Optimisation of the approach can be achieved by careful model plant selection, limiting target nutrient applications to less than that required for growth to plateau, and including a maximal productivity reference
Accounting for soil water improves prediction of lentil phenology for improved frost and heat stress management
No full textLentils in Australia are primarily grown in temperate and Mediterranean climates, especially in the southern and western regions of the country. As in other parts of the world, lentil yields in these areas are significantly influenced by factors such as frost, heat, and drought, contributing to variable production. Therefore, selecting appropriate lentil varieties and determining optimal sowing times that align with favourable growing conditions is crucial. Accurate predictions of crop development are essential in this context. Current models mainly rely on photoperiod and temperature to predict lentil phenology; however, they often neglect the impact of soil water on flowering and pod set. This study investigated whether incorporating soil water as an additional factor could improve predictions for these critical growth stages. The modified model was tested using 281 data points from various lentil experiments that examined the timing of flowering (61–147 days) and pod set (77–163 days) across different combinations of location, variety, sowing time, and season. The results indicated that including soil water in the prediction model achieved an R² value of 0.84 for flowering and 0.83 for pod set. The normalised root mean square error (NRMSE) was 0.07, and Lin's concordance correlation coefficient (LinCCC) was 0.91. The model produced an R² of 0.88, an NRMSE of 0.05, and a LinCCC of 0.93 flowering compared to the default model, which yielded an R² of 0.24, an NRMSE of 0.17, and a LinCCC of 0.36 for flowering. A limited sensitivity analysis of the modified model showed that variations in initial soil water and in-season rainfall significantly affected the timing of flowering and pod set. Additionally, we employed a probability framework to assess the crop's vulnerability to the last frost day and early heat stress events during the reproductive stage. This approach provided valuable insights for decision-making to mitigate risks associated with frost and heat stress. Our study suggests that integrating soil water dynamics into lentil phenology models improves the accuracy and precision of predictions regarding the timing of flowering and pod set. These improvements lead to better forecasts, ultimately helping to minimise damage from frost and heat stress during lentil cultivation and can better explain the effect of climate variability
Improved Management of Charcoal Rot of Strawberry in Australia with Soil Fumigation and Totally Impermeable Film
No full textCharcoal rot of strawberry [Fragaria ×ananassa (Duchesne)] caused by the soil-borne fungus Macrophomina phaseolina (Tassi) Goid results in significant plant losses each year in Australia. Before the current research, industry applied the soil fumigants 1,3-dichloropropene and chloropicrin in combination to the bed (strip fumigation) under low-density polyethylene film (LDPE) as the standard practice to manage the disease. We conducted column and field experiments to evaluate soil fumigation with 1,3-dichloropropene/chloropicrin under totally impermeable film (TIF) and broadacre application (treatment of beds and inter-rows) for control of M. phaseolina and charcoal rot compared with the previous standard practice. The results showed that treatment under TIF increased the concentration × time (CT) values of fumigants in soil by up to 38% compared with those of LDPE. Strip fumigation under TIF reduced DNA concentrations of M. phaseolina in soil (0–10 cm) by 65%, charcoal rot by 93%, and increased fruit yields by 37% compared with application under LDPE. Furthermore, broadacre fumigation reduced DNA concentrations of M. phaseolina by an average of 55%, charcoal rot by 65%, and increased fruit yields by 40% compared with those of strip fumigation under LDPE. This work demonstrates the effectiveness of improved fumigation practices for minimizing the impact of charcoal rot in strawberry
Taking shortcuts: lowering harvest height to restrict colonisation of cereal stubble by Fusarium pseudograminearum
No full textContext. Many wheat producers are increasing the biomass of cereal stubble retained after harvest through the adoption of stripper front harvesters, which result in taller standing stubble. Aims. We investigated whether taller stubble affects the survival and dispersal of Fusarium pseudograminearum (Fp), the causative agent of Fusarium crown rot (FCR). Methods. Field experiments at two sites in northern New South Wales were run for 3 years to investigate whether taller cereal stubble in Year 1 facilitated additional Fp colonisation, and subsequent effects on dispersal of Fp inoculum from chickpea harvest in Year 2 and FCR infection and expression in cereal crops in Year 3. Culturing and quantitative polymerase chain reaction (qPCR) methods assessed Fp colonisation and future disease risks. Key results. In taller cereal stubble, Fp colonised an additional 91–92% of the stubble length in the 6 months post-harvest and persisted at higher levels for at least 1 year than did the shorter cereal stubble. Cutting cereal stubble short (in Year 1) therefore successfully restricted further colonisation by Fp.Significant displacement of Fp in the crown 6 months post-harvest resulted in significant decreases in Fp DNA overall; however, long-term survival of Fp was observed 10–20 cm above the crown. Conclusions. Different residue management scenarios did not increase FCR risk for Year 3, likely owing to high inoculum levels across all treatments and unseasonably wet conditions in Years 2–3. Implications. We provide important field-validation of Fp colonisation in standing cereal stubble and discuss implications for FCR management across regions and seasons
‘US-Gallasch’: A New Citrus Rootstock 60 Years in the Making
No full text‘US-Gallasch’ is a new citrus rootstock released by the Queensland Department of Primary Industries (QDPI) for wider testing in nurseries and by citrus growers. This hybrid selection was originally produced from a cross made in 1962, in the citrus breeding program of the US Department of Agriculture (USDA) at Indio, CA, USA. The major positive attributes of this rootstock are excellent resistance to Citrus tristeza virus (CTV), salt tolerance, graft union compatibility, and induction of moderate tree size, with good productivity and fruit quality. ‘US-Gallasch’ can be uniformly and efficiently propagated by apomictic seed, showing desirable nursery growth characteristics. The release of this rootstock follows a long path from its original creation, with research on two continents and the revelation that this parental combination warrants closer consideration by rootstock breeders
Phenotypic and Agronomic Variation Within Naturalized Medicago polymorpha L. (Burr Medic) in Subtropical Queensland, Australia, and Relationships with Climate and Soil Characteristics
No full textTo characterize the naturalized population of burr medic (Medicago polymorpha L.), a valuable pasture legume, in subtropical Queensland, Australia, a collection of 1747 lines from 107 sites in 11 regions was grown, and 26 phenotypic and agronomic attributes were recorded. This data matrix was analyzed by cluster, principal co-ordinates, discriminant and correlation analyses to examine line relationships based on plant attributes and their association with site characteristics of climate and soil. Among the wide polymorphism of attributes across the collection zone, there were a number of notable phenotypic associations. One of these, with large green leaves, minimally dentate leaf margins, and light purple petioles, was widely distributed. Three others, one with a distinctive magenta leaf mark, dark purple petioles, and an upright habit; one with those same attributes but with a prostrate habit; and one with grey-green leaves, high frost resistance, and the ability to stay green and to produce high pod yields, were associated with climatic and soil characteristics in the north, east, and south of the collection zone, respectively. Days to flowering were longer in lines from saline soils at lower altitude, and plant vigor was greatest in lines from more fertile soils with higher rainfall. A wide variation in time to flower of lines at all collection sites contributes to the adaptation of M. polymorpha in subtropical Queensland and potentially to its persistence with future climate change
Variable response to aerial culling demonstrates adaptability of feral pigs
No full textFeral pigs represent significant threats to the environments where they are introduced, both to the native flora and fauna, as well as agriculture and production systems as vectors of disease. Despite being subject to intermittent, intensive management efforts across much of their invaded range, how feral pigs respond spatially to control programs remains poorly understood. To examine behavioural responses to short-term aerial culling (current practice), feral pigs were fitted with GPS collars in southern Queensland, Australia at two sites with aerial culling and one nil-treatment site. Using continuous time movement models and recurse analysis, changes to feral pig home range size, location, overlap between individuals, and use of cover were compared between two consecutive months, pre- and post- aerial culling, or rainfall at the nil-treatment site. Significant disturbance did not have a consistent impact on feral pig spatial behaviour in terms of home range size, location, or home range overlap between individuals. Likewise, changes in daily activity and cover use by feral pigs were not consistent in response to aerial control. This was also reflected at the site with no aerial control, where feral pig spatial behaviour varied on a month-to-month basis and was inconsistent between the examined periods. Collectively, these results indicate that aerial culling did not represent a significant enough disturbance to induce changes in feral pig spatial behaviour, and highlights the plasticity and high spatiotemporal variability of feral pig habitat use on a month-to-month basis. The findings also support the use of aerial culling to manage pig populations, particularly during exotic disease incursions where dispersal of animals to uninfected areas must be avoided
Increased genomic predictive ability in mango using GWAS-preselected variants and fixed-effect SNPs
No full textGenomic selection (GS) using whole-genome sequencing (WGS) data has potential to improve breeding value accuracy in fruit trees, but previous studies have reported limited gains compared to high-density marker sets. Incorporating preselected variants identified through genome-wide association studies (GWAS) is a promising strategy to enhance the predictive power of WGS data. We investigated whether incorporating GWAS-preselected variants and fixed-effect markers into genomic best linear unbiased prediction (GBLUP) models improves predictive ability for fruit blush color (FBC), average fruit weight (AFW), fruit firmness (FF), and trunk circumference (TC) in mango ( Mangifera indica L.). The study used 225 gene pool accessions from the Queensland Department of Primary Industries in Australia, with phenotypes collected between 1999 and 2024. Predictive ability was assessed using models that ignored or accounted for population structure using fixed principal components. Accounting for population structure led to substantial reduction in predictive ability across all traits, suggesting that initially high predictive abilities may have been partly driven by genetic differences between subpopulations. GWAS-preselected variants improved predictive abilities compared to using all WGS data, especially when population structure was accounted for in both parental and 5-fold cross-validation. Gains under parental validation reached 0.28 for AFW (from 0.30 to 0.58) and 0.06 for FBC (from 0.44 to 0.50). In 5-fold cross validation, gains were up to 0.16 for AFW (from 0.32 to 0.48) and 0.10 for FBC (from 0.35 to 0.45). This suggests that prioritizing markers that better capture relationships at causal loci can improve predictive ability. Fixed-effect SNPs improved predictive ability of WGS data, particularly for FBC, with increases of up to 0.18 (from 0.44 to 0.62). The combination of GWAS-preselected variants and fixed-effect markers yielded the highest improvements in predictive ability for FBC and TC. GWAS identified 5 trait-associated SNPs for FBC, 11 for AFW, and 8 for TC. These results demonstrate that leveraging GWAS-preselected variants and fixed-effect SNPs improves predictive ability, potentially enhancing breeding efficiency in fruit trees