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The use of participatory approaches in the development and extension of fall armyworm management practices for the Australian vegetable industry
No full textSpodoptera frugiperda (fall armyworm) was first detected in Northern Australia in
February 2020 and its establishment caused economic losses to sweet corn and maize. We used Participatory Action Research (PAR) methods to co-develop and deliver the best management
options (BMOs) for the sweet corn industry and valuable information for other crops. Various
extension methods combined with three FAW BMOs demonstrations in sweet corn were
delivered. A total of 402 vegetable industry participants and service providers engaged in the
project. Over 60% rated the field day as a useful resource for engaging, sharing, learning, and
accessing BMOs. Surveys showed that the PAR improved the participant’s knowledge of pest
biology and natural enemies, skills in FAW diagnostics, and changed pest management
practices. It indicates regular crop monitoring and choosing appropriate insecticides with
targeted applications to eggs and larvae can improve FAW control and minimise insecticide resistance development
Assessing the Pathogenicity of Berkeleyomyces rouxiae and Fusarium oxysporum f. sp. vasinfectum on Cotton (Gossypium hirsutum) Using a Rapid and Robust Seedling Screening Method
No full textCotton (Gossypium spp.) is the most important fibre crop worldwide. Black root rot and Fusarium wilt are two major diseases of cotton caused by soil-borne Berkeleyomyces rouxiae and Fusarium oxysporum f. sp. vasinfectum (Fov), respectively. Phenotyping plant symptoms caused by soil-borne pathogens has always been a challenge. To increase the uniformity of infection, we adapted a seedling screening method that directly uses liquid cultures to inoculate the plant roots and the soil. Four isolates, each of B. rouxiae and Fov, were collected from cotton fields in Australia and were characterised for virulence on cotton under controlled plant growth conditions. While the identities of all four B. rouxiae isolates were confirmed by multilocus sequencing, only two of them were found to be pathogenic on cotton, suggesting variability in the ability of isolates of this species to cause disease. The four Fov isolates were phylogenetically clustered together with the other Australian Fov isolates and displayed both external and internal symptoms characteristic of Fusarium wilt on cotton plants. Furthermore, the isolates appeared to induce varied levels of plant disease severity indicating differences in their virulence on cotton. To contrast the virulence of the Fov isolates, four putatively non-pathogenic Fusarium oxysporum (Fo) isolates collected from cotton seedlings exhibiting atypical wilt symptoms were assessed for their ability to colonise cotton host. Despite the absence of Secreted in Xylem genes (SIX6, SIX11, SIX13 and SIX14) characteristic of Fov, all four Fo isolates retained the ability to colonise cotton and induce wilt symptoms. This suggests that slightly virulent strains of Fo may contribute to the overall occurrence of Fusarium wilt in cotton fields. Findings from this study will allow better distinction to be made between plant pathogens and endophytes and allow fungal effectors underpinning pathogenicity to be explored
The ‘best’ legume rotation for southern cane growers
No full textGrain legume rotations on sugarcane farms have become well established in the Bundaberg/Isis/Maryborough cane supply districts, as a result of RDE efforts of the Sugar Yield Decline Joint Venture. However, sugarcane growers wanted information on what was the ’‘best’’ legume to grow in rotation with sugarcane. Two separate projects with funding support from both the Grains and Sugar industry with a grower/advisor steering committee implemented a field trial to evaluate the performance of different varieties of peanut, soybean and mungbean along with pigeon pea, traditional cowpea and bare fallow options. These rotation options were then assessed to determine the effect on the productivity of the subsequent sugarcane crop. A cane monoculture treatment was also maintained to provide a reference. The data from this experiment demonstrated that soybean and peanuts were valuable rotation options that boosted grower profitability and productivity of the subsequent sugarcane crop. The trial also highlighted the potential of pigeon pea as a rotation option. Red Caloona cowpea was the ‘best’ legume in terms of nitrogen contribution, but this did not translate into the best productivity of the subsequent sugarcane crop. Whilst the peanut rotation provided the ‘best’ profitability, by the end of the first ratoon, A6785 soybean rotation provided the ‘best’ cumulative cane yield. All legume rotations significantly reduced root lesion nematode populations when measured 6 months after cane establishment. The poor performance of sugarcane grown after Onyx mungbean was probably reflective of the high numbers of root knot nematodes that proliferated on that crop. A sugarcane monoculture had the lowest productivity and the lowest gross margin in the plant-cane phase. Data collected from this experiment suggests that growers would benefit from a legume decision support tool to better assist growers in making profitable farming system decisions
Board assignment heuristics for nail laminated out-of-grade timber
No full textStructural sawn timber, sourced from softwood plantations, is widely used in lightweight timber-framed residential housing and in engineered wood products for contemporary mass timber construction. However, a significant proportion of milled timber boards are considered ?out-of-grade?, failing to attain a structural grade under existing classifications systems due to various stiffness, strength, and/or utility-limiting features. This study investigates the potential of controlled lamination techniques to produce structurally usable laminated timber products from out-of-grade timber, using a minimal number of requisite boards. Numerical and experimental methods were employed to compare different board assignment heuristics, in terms of reducing the stiffness variability in laminated board populations. The results indicate that controlled board locations produced remarkably consistent laminated products, achieving very low variability even with a minimum lamination of only two boards. The findings of this paper suggest that controlled lamination techniques have the potential to transform low-value out-of-grade timber into a valuable resource for value-added applications, challenging the existing market perception that out-of-grade timber lacks structural usability
Seminal root angle is associated with root system architecture in durum wheat
No full textOptimal root system architecture (RSA) is critical for efficient resource capture in soils, hence being an interest in crop breeding. Seminal root angle (SRA) at the seedling stage in durum wheat has been suggested to be a good indicator of RSA. However, research on correlating such laboratory-based seedling root phenotyping to RSA at later phases of plant growth is limited, resulting in the importance of root trait variation seen in seedlings often being overstated. To explore the role of SRA in modifying RSA at later phases of plant growth, we assessed 11 genotypes contrasting in SRA (wide and narrow), grown in a rhizobox designed for phenotyping root systems of plants during late-tillering. Aboveground traits and root dry mass in different soil depths and across the entire soil volume were measured manually, while root architectural traits were extracted using image analysis and summarised by multiple factor analysis to describe RSA. When comparing the wide and narrow genotypes, no differences were detected for aboveground traits and total root dry mass. However, differences were observed in the allocation of root dry mass at different depths. The wide and narrow genotypes showed distinct RSAs, particularly in the upper soil (0–30 cm). The wide genotypes exhibited a ‘spread-out’ root system with dense and thin roots, whereas the narrow genotypes had a compact root system with fewer but thicker roots. Our study demonstrated a clear difference in RSA between the wide and narrow genotypes, highlighting the association between SRA on the direction and distribution of root growth in plants at later growth stages
Improving our understanding of the persistence, bioavailability and crop toxicity risks of soil residual herbicides
No full textThe use of residual herbicides for weed control in cropping systems with diverse crop rotations requires a thorough knowledge of herbicide behaviour to minimise the risk of plant-back crop damage. This is especially the case when multiple mode-of-action groups are applied to counteract the threat of herbicide resistant weeds or populations. Adding to this challenge is an increasing probability of more extreme weather events, including more frequent or longer drought events, which can have strong effects on herbicide persistence. Although growers and advisors often have a good qualitive and experiential grasp of herbicide behaviour and plant back risk, more quantitate and site-specific information could help refine planning and operational decisions to avoid costly crop damage.
This presentation introduces a new project entitled ‘Geospatial analytics to predict the impact of residual herbicides on establish and yield’ that aims to validate several tools to help better understand the likelihood of herbicide carryover and potential crop damage. The project will develop and couple geospatial models of herbicide persistence with ‘pedo-transfer functions’ and leaf tissue analysis to quantify crop toxicity risk. The presentation will outline the proposed project framework and discuss some recent findings from field experiments to illustrate potential practical implications for grain growers and advisors
Demonstrating integrated weed tactic across farming systems
No full textGlyphosate resistance is everywhere! This ever-increasing issue facing weed management on cotton and grains systems is forcing growers to look for alternatives. None of these alternatives are as easy to incorporate into farming systems as glyphosate – a once in a century herbicide.
A series of workshops on weed management issues was held in conjunction with cotton and grain growers in the major cropping areas of the Northern Region. Aside from glyphosate and group 1 resistance, the major issue growers are facing is incorporating post-emergent herbicides into their systems. Post-emergent herbicides require knowledge of proposed crop rotations, soil type, climatic conditions, herbicide properties and incorporation requirements on top of weed spectrum.
It has been over two decades since pre-emergent herbicides were used commonly in cotton systems. It this time there has been a generational change in the growers and agronomists who aren’t confident in incorporating pre-emergent herbicides into their programs. Additionally, as optical spray technology is becoming more common, growers are now using high rates of pre- and post-emergent herbicides on patches of weeds. Some of these post-emergent herbicides can have residual properties at the rates being used.
Our research has shown that residual herbicides applied to cotton at planting had some detrimental early-season effects on the following wheat and chickpea crops however these effects did not consistently result in yield reductions. Of the range of fallow pre-emergent herbicides applied before the cotton crop, only imazapic had a detrimental effect on the cotton crop. High rates of 2,4-D that have damaged subsequent cotton commercially did not show detrimental effects in the trials we conducted. High rates of Balance, Sharpen, Starane and Voraxor that can be applied through camera sprayers are likely to cause damage to subsequent cotton crops
Field biology of Cleome gynandra L.: A difficult to manage weed of cultivated vegetable crops
No full textSpider plant (Cleome gynandra L.) has been identified as an emerging significant weed of cultivated vegetable crops in southeast Queensland (SEQ). In Australia, the importance of spider plant relates to its biological characteristics and the difficulty land managers are facing with its management. It’s a prolific seed producer, can accumulate biomass rapidly at high temperatures and soil moisture levels and can tolerate extended drought. Two separate studies were carried out: the first controlled environment study investigated root-shoot growth, biomass accumulation and raceme growth under four substrate moisture (viz., 90 to 100%, 70 to 80%, 50 to 60% or 30 to 40% of the FC) and two temperature levels (25/35℃, 15/25℃) which represent average Summer and Winter temperatures in SEQ. The second study investigated seed production and seed-pod morphology during the Summer and Winter periods. Results demonstrated that both soil moisture, temperature and their interaction can profoundly impact root-shoot growth, biomass accumulation, and raceme growth. Adequate soil moisture and Summer temperatures (25/35℃) contributed to taller stature (17%), more shoot dry wt (25%) and greater raceme growth (20%) compared to plants under Winter temperatures (15/25℃). However, moisture stress increased root depth by 66% and advanced flowering time by 5 days. The interaction of temperature and moisture increased dry weight by 330 to 510% and raceme growth by 223 to 265%. The Summer plants produced over 70,000 seeds plant-1 with significantly higher pod length, width, and seeds pod-1 than the Winter plants. Since cultivated vegetable crops are irrigated, knowledge of the combined effects of temperature and soil moisture will provide better understanding on the field biology of spider plant under fixed crop management practices. The outcome of this research will contribute to better management of the persistent spider plants in cultivated crops
Moderate Phosphorus Addition to Field-Grown Bananas Enhanced Soil Microbial Enzyme Activities but Had Negligible Impacts on Bacterial, Fungal, and Nematode Diversity
No full textOn commercial banana (Musa spp.) plantations, soils are often supplemented with phosphorus (P) fertiliser to optimise production. Such additions may influence the diversity and function of soil microbial communities, which play important roles in P cycling and affect plant fitness. Here, we characterised the effects of P addition on the diversity and function of banana-associated microbial communities. P addition was associated with significant increases in soil P and the activities of alpha-glucosidase, chitinase, arylsulphatase, and acid phosphatase, but not beta-glucosidase or xylosidase. P addition also expedited bunch emergence and harvest, but did not influence fruit yield, plant height, or foliar P. There were no significant effects of P addition on the alpha or beta diversity of bacterial, fungal, and nematode communities, including members of the core microbiome. The only exceptions to this was an increase in the relative abundance of a Fusarium population in roots. These results indicate that phosphorus application to banana soils may stimulate microbial enzyme activities with minor or negligible effects on microbial diversity
Engaging local voices: farmers, rural communities, and ecological restoration
No full textThis chapter outlines engagement frameworks and strategies for understanding and improving the involvement of farmers and their communities in ecological restoration initiatives. It considers approaches for bringing together participants with differing perspectives and interests to address environmental challenges, in ways that account for both biophysical and socio-political ecologies. The presentation of two case studies highlights the context, challenges and promise of community engagement, along with overarching principles that support effective community-focused initiatives