Getting value out of your sensory testing - the difference from control test

Non-parametric difference tests such as triangle and duo-trio tests traditionally are used to establish differences or similarities between products. However they only supply the researcher with partial answers and often further testing is required to establish the nature, size and direction of differences. This paper looks at the advantages of the difference from control (DFC) test (also known as degree of difference test) and discusses appropriate applications of the test. The scope and principle of the test, panel composition and analysis of results are presented with the aid of suitable examples. Two of the major uses of the DFC test are in quality control and shelf-life testing. The role DFC takes in these areas and the use of other tests to complement the testing is discussed. Controls or standards are important in both these areas and the use of standard products, mental and written standards and blind controls are highlighted. The DFC test has applications in products where the duo-trio and triangle tests cannot be used because of the normal heterogeneity of the product. While the DFC test is a simple difference test it can be structured to give the researcher more valuable data and scope to make informed decisions about their product.

Field evaluation of a plant activator, captan, chlorothalonil, copper hydroxide, iprodione, mancozeb and strobilurins for the control of citrus brown spot of mandarin

Brown spot (caused by Alternaria alternata) is a major disease of citrus in subtropical areas of Australia. A number of chemicals, the strobilurins azoxystrobin, trifloxystrobin, pyraclostrobin and methoxycrylate, a plant activator (acibenzolar), copper hydroxide, mancozeb, captan, iprodione and chlorothalonil/pyrimthanil were tested in the field for its control. Over three seasons, trees in a commercial orchard received 16, 14 and 7 fungicide sprays, respectively, commencing at flowering in the first season, and petal fall in the later seasons. In all experiments, the strobilurins used alone, or incorporated with copper and mancozeb, were as effective as, or better than the industry standard of copper and mancozeb alone. The only exception was trifloxystrobin, which when used alone was less effective than the industry standard. Acibenzolar used alone was ineffective. Applying a mixture of azoxystrobin and acibenzolar was found to reduce the incidence of brown spot compared with applying azoxystrobin alone but, in either case, disease levels were not found to be significantly different to the industry standard. Captan, iprodione and chlorothalonil/pyrimthanil were as effective as the industry standard. The incidence and severity of rind damage were significantly lowest in the azoxystrobin, methoxycrylate, iprodione and chlorothalonil/pyrimthanil treatments. Medium and high rates of trifloxystrobin (0.07 g/L, 0 .15 g/L) and pyraclostrobin (0.8 g/L, 1.2 g/L) applied alone were the only treatments found to be IPM-incompatible as shown by the elevated level of scale infection on fruit.

Effect of the Queensland Shark Control Program on non target species : whale, dugong, turtle and dolphin : a review

The Queensland Shark Control Program (QSCP) aims to protect swimmers at ten beach areas on the east coast of Queensland between Cairns (17°S) and the Gold coast (28°S). Since its inception in 1962 it has deployed shark nets and baited drumlines in a `mixed gear strategy' that adapts the type of gear to the characteristics of a site (e .g . extreme tidal range, high energy wave action, or proximity of turtle breeding areas) . The policy has provided swimmer protection, and the incidental capture of non-target species has been lower than that resulting from deployment of nets alone (Dudley 1997; Gribble et al. 1998b). The QSCP is the only major public-safety shark-control program to routinely use mixed gear. Both the New South Wales (Holt 1998) and KwaZulu-Natal (Dudley 1998) programs use nets exclusively, although the KwaZulu-Natal program has recently tested drumlines on an experimental basis (Dudley 1998; Dudley, personal communication).

The Introduction of Transgenes to Control Blackheart in Pineapple: Biolistics Vs Agrobacterium Transformation, in 'Contributing to a Sustainable Future'

Techniques for the introduction of transgenes to control blackheart by particle bombardment and Agrobacterium co-transformation have been developed for pineapple cv. Smooth Cayenne. Polyphenol oxidase (PPO) is the enzyme responsible for blackheart development in pineapple fruit following chilling injury. Sense, anti-sense and hairpin constructs were used as a means to suppress PPO expression in plants. Average transformation efficiency for biolistics was approximately 1% and for Agrobacterium was approximately 1.5%. These results were considered acceptable given the high regeneration potential of between 80-90% from callus cultures. Southern blot analysis revealed stable integration of transgenes with lower copy number found in plants transformed with Agrobacterium compared to those transformed by biolistics. Over 5000 plants from 55 transgenic lines are now undergoing field evaluation in Australia

Microgrid frequency control using multiple battery energy storage system (BESSs)

The work is a report of research on using multiple inverters of Battery Energy Storage Systems with angle droop controllers to share real power in an isolated micro grid system consisting of inertia based Distributed Generation units and variable load. The proposed angle droop control method helps to balance the supply and demand in the micro grid autonomous mode through charging and discharging of the Battery Energy Storage Systems while ensuring that the state of charge of the storage devices is within safe operating conditions. The proposed method is also studied for its effectiveness for frequency control. The proposed control system is verified and its performance validated with simulation software MATLAB/SIMULINK.

Timing of fungicide applications for control of husk spot caused by Pseudocercospora macadamiae in macadamia

Pseudocercospora macadamiae is an important pathogen of macadamia in Australia, causing a disease known as husk spot. Growers strive to control the disease with a number of carbendazim and copper treatments. The aim of this study was to consider the macadamia fruit developmental stage at which fungicide application is most effective against husk spot, and whether application of copper-only applications at full-size fruit developmental stage toward the end of the season contributed to effective disease control. Fungicides were applied to macadamia trees at four developmental stages in three orchards in two subsequent production seasons. The effects of the treatments on disease incidence and severity were quantified using area under disease progress curve (AUDPC) and logistic regression models. Although disease incidence varied between cultivars, incidence and severity on cv. A16 showed consistent differences between the treatments. Most significant reduction in husk spot incidence occurred when spraying commenced at match-head sized-fruit developmental stage. All treatments significantly reduced husk spot incidence and severity compared with the untreated controls, and a significant positive linear relationship (R2 = 73%) between AUDPC and severity showed that timing of the first fungicide application is important for effective disease control. Application of fungicide at full-size fruit stage reduced disease incidence but had no impact on premature fruit drop.

Damage potential of an introduced biological control agent Agonosoma trilineatum (F.) on bellyache bush (Jatropha gossypiifolia L.)

The seed-feeding jewel bug, Agonosoma trilineatum (F.), is an introduced biological control agent for bellyache bush, Jatropha gossypiifolia L. To quantify the damage potential of this agent, shadehouse experiments were conducted with individual bellyache bush plants exposed to a range of jewel bug densities (0, 6 or 24 jewel bugs/plant). The level of abortion of both immature and mature seed capsules and impacts on seed weight and seed viability were recorded in an initial short-term study. The ability of the jewel bug to survive and cause sustained damage was then investigated by measuring seed production, the survival of adults and nymph density across three 6-month cycles. The level of seed capsule abortion caused by the jewel bug was significantly affected by the maturity status of capsules and the density of insects present. Immature capsules were most susceptible and capsule abortion increased with jewel bug density. Similarly, on average, the insects reduced the viability of bellyache bush seeds by 79% and 89% at low and high densities, respectively. However, sustaining jewel bug populations for prolonged periods proved difficult. Adult survival at the end of three 6-month cycles averaged 11% and associated reductions in viable seed production ranged between 55% and 77%. These results suggest that the jewel bug has the potential to reduce the number of viable seeds entering the soil seed bank provided populations can be established and maintained at sufficiently high densities.

The introduction of transgenes to control blackheart in pineapple (Ananas Comosus L.) cv. Smooth Cayenne by microprojectile bombardment

A transformation technique for the introduction of transgenes to control blackheart by particle bombardment has been developed for pineapple cv. Smooth Cayenne. Leaf callus cultures capable of high frequency organogenesis with a short regeneration time were used as explant material. Gus and gfp reporter genes were used to observe and determine transient and stable expression. The ppo gene, isolated from pineapple, was introduced to control blackheart. Co-transformation occurred with constructs containing the nptII gene conferring geneticin resistance. We have recovered 15 independent transgenic gus and gfp lines each from 8 separate experiments and 22 ppo lines from 11 experiments. Gus, gfp, ppo and nptII positive plants have been regenerated, which have been shown by Southern blot analysis to be stable transgenics containing multiple copies of the introduced genes. These results show that biolistic gene delivery in pineapple can be successfully achieved at an acceptable efficiency of 0.21-1.5% for genetic improvement of 'Smooth Cayenne', the industry standard throughout the world.

Odour Emissions from Tunnel Ventilated Poultry Housing

In Australia, factors such as local planning processes, urban encroachment into rural areas and intensification of the poultry industry have increased the potential for odour and dust nuisance. At present, accurate estimates of odour emissions from mechanically ventilated poultry housing systems do not exist for Australian conditions. This has made the poultry industry vulnerable to unsubstantiated criticism. Recently, the Australian poultry industry have made a significant investment in research to obtain accurate estimates of odour, dust and volatile chemical emission rates from typical poultry housing systems. This paper describes the measurement of odour emissions from tunnel ventilated poultry housing systems in different climatic zones in Queensland and Victoria, Australia (humid sub-tropical and Mediterranean respectively) during two seasons (summer and winter). Samples were collected at defined intervals over typical batch production cycles to define the odour emission profiles. These samples were analysed using dynamic olfactometry according to the Australian Standard 4323.3 to derive the odour concentration values. Ventilation rates were measured concurrently, allowing the calculation of odour emission rates. Odour concentration and emission rates were assessed in terms of ventilation rate, ambient and shed air temperature and relative humidity and litter moisture status. Odour emission rates varied with bird age. Seasonal differences in odour emission rate were also observed.

Non-target impacts of poison baiting for predator control in Australia

1. Mammalian predators are controlled by poison baiting in many parts of the world, often to alleviate their impacts on agriculture or the environment. Although predator control can have substantial benefits, the poisons used may also be potentially harmful to other wildlife. 2. Impacts on non-target species must be minimized, but can be difficult to predict or quantify. Species and individuals vary in their sensitivity to toxins and their propensity to consume poison baits, while populations vary in their resilience. Wildlife populations can accrue benefits from predator control, which outweigh the occasional deaths of non-target animals. We review recent advances in Australia, providing a framework for assessing non-target effects of poisoning operations and for developing techniques to minimize such effects. We also emphasize that weak or circumstantial evidence of non-target effects can be misleading. 3. Weak evidence that poison baiting presents a potential risk to non-target species comes from measuring the sensitivity of species to the toxin in the laboratory. More convincing evidence may be obtained by quantifying susceptibility in the field. This requires detailed information on the propensity of animals to locate and consume poison baits, as well as the likelihood of mortality if baits are consumed. Still stronger evidence may be obtained if predator baiting causes non-target mortality in the field (with toxin detected by post-mortem examination). Conclusive proof of a negative impact on populations of non-target species can be obtained only if any observed non-target mortality is followed by sustained reductions in population density. 4. Such proof is difficult to obtain and the possibility of a population-level impact cannot be reliably confirmed or dismissed without rigorous trials. In the absence of conclusive evidence, wildlife managers should adopt a precautionary approach which seeks to minimize potential risk to non-target individuals, while clarifying population-level effects through continued research.

Phylogenetic considerations for predicting the host range of Ustilago sporoboli-indici, a potential biological control agent for Sporobolus species in Australia

The ribosomal DNA internal transcribed spacer region was amplified and sequenced from a selection of specimens of the Sporobolus smut Ustilago sporoboli-indici. Phylogenetic comparison with other Ustilago and Sporisorium species revealed strong support for an evolutionary radiation of Ustilago species infecting the Chloridoideae and Pooideae, of which U. sporoboli-indici forms a major lineage. Comparisons are made with other groups of plant pathogenic fungi, and it is concluded that phylogenetic analyses of potential biocontrol agents are useful for identifying pathogens that are derived from evolutionary lineages that parasitize a wide range of unrelated plants. Such pathogens are less desirable as biocontrol agents as they may have a greater likelihood of infecting plants outside their normal host ranges.

Performance evaluation of a distributed concurrency control algorithm

Concurrency control (CC) algorithms are important in distributed database systems to ensure consistency of the database. A number of such algorithms are available in the literature. The issue of performance evaluation of these algorithms has been recognized to be important. However, only a few studies have been carried out towards this. This paper deals with the performance evaluation of a CC algorithm proposed by Rosenkrantz et al. through a detailed simulation study. In doing so, the algorithm has been modified so that it can, within itself, take care of the redundancy in the database. The influences of various system parameters and the transaction profile on the response time and on the degree of conflict are considered. The entire study has been carried out using the programming language SIMULA on a DEC-1090 system.

Biological control of parthenium (Parthenium hysterophorus) in Australian rangeland translates to improved grass production.

Biological control of parthenium, a major weed in grazing areas in Australia, was initiated in the mid 1970s. Since then, nine species of insects and two rust fungi have been introduced. Evaluation using pesticide exclusion at two sites (Mt. Panorama and Plain Creek) in Queensland, Australia, revealed that classical biological control had a significant negative effect on the target weed, but the impact varied between years. In this study, I quantified the effects of biological control of parthenium on grass production. Grass production declined with the increase in parthenium biomass. Significant increase in grass production due to biological control was observed, but only in 1 of 4 yr at Mt. Panorama and 2 of 4 yr at Plain Creek. At Mt. Panorama, there was a 40% increase in grass biomass in 1997 because of defoliation by Zygogramma bicolorata and galling by Epiblema strenuana. At Plain Creek, grass biomass increased by 52% in 1998 because of E. strenuana and by 45% in 2000 because of combined effects of E. strenuana and the summer rust Puccinia melampodii. This study provides evidence on the beneficial effects of biological control of parthenium in areas under limited grazing.

Transgenic gene silencing strategies for virus control.

Co-suppression of transgenes and their homologous viral sequences by RNA silencing is a powerful strategy for achieving high-level virus resistance in plants. This review provides a brief overview of RNA silencing mechanisms in plants and discusses important transgene construct design features underpinning successful RNA silencing-mediated transgenic virus control. Application of those strategies to protect horticultural and field crops from virus infection and results of field tests are also provided. The effectiveness and stability of RNA-mediated transgenic resistance are assessed taking into account effects of viral, plant and environmental factors.

Utilizing the assassin bug, Pristhesancus plagipennis (Hemiptera: Reduviidae), as a biological control agent within an integrated pest management programme for Helicoverpa spp. (Lepidoptera: Noctuidae) and Creontiades spp. (Hemiptera: Miridae) in cotton

Helicoverpa spp. and mirids, Creontiades spp., have been difficult to control biologically in cotton due to their unpredictable temporal abundance combined with a cropping environment often made hostile by frequent usage of broad spectrum insecticides. To address this problem, a range of new generation insecticides registered for use in cotton were tested for compatibility with the assassin bug, Pristhesancus plagipennis (Walker), a potential biological control agent for Helicoverpa spp. and Creontiades spp. Indoxacarb, pyriproxifen, buprofezin, spinosad and fipronil were found to be of low to moderate toxicity on P. plagipennis whilst emamectin benzoate, abamectin, diafenthiuron, imidacloprid and omethaote were moderate to highly toxic. Inundative releases of P. plagipennis integrated with insecticides identified as being of low toxicity were then tested and compared with treatments of P. plagipennis and the compatible insecticides used alone, conventionally sprayed usage practice and an untreated control during two field experiments in cotton. The biological control provided by P. plagipennis nymphs when combined with compatible insecticides provided significant (P<0.001) reductions in Helicoverpa and Creontiades spp. on cotton and provided equivalent yields to conventionally sprayed cotton with half of the synthetic insecticide input. Despite this, the utilization of P. plagipennis in cotton as part of an integrated pest management programme remains unlikely due to high inundative release costs relative to other control technologies such as insecticides and transgenic (Bt) cotton varieties.