Effect of fumigation temperature on the efficacy of phosphine against strongly resistant psocids liposcelis bostrychophila (Pscodoptera: Liposcelididae)

Species of Liposcelis psocids have emerged as major pests of stored grain in Australia in recent years. Several populations have been detected with high resistance to phosphine, the major chemical treatment. Highest resistance has been detected in the cosmopolitan species Liposcelis bostrychophila. As part of a national resistance management strategy to maintain the viability of phosphine, we are developing minimum effective dosage regimes (concentration x time) required to control all life stages of resistant L. bostrychophila at a range of grain temperatures. Four concentrations of phosphine, 0.1, 0.17, 0.3 aid 1 mg/L, were evaluated for their effectiveness against strongly resistant L. bostrychophila at a series of fumigation temperatures: 20, 25, 30 and 35°C. Results were recorded as the least number of days taken to achieve population extinction. We found that, at any fixed concentration of phosphine, time to population extinction decreased as fumigation temperature increased from 20 to 30°C. For example, at 0.1 mg/L, it took more than 14 days at 20°C to completely control these insects, whereas at 30°C it took only seven days. Increase in fumigation temperature from 25OC to 30°C dramatically reduced the exposure period needed to achieve population extinction of resistant psocids. For example, a dose of 0.17 mg/L over six days at 30°C completely controlled strongly resistant L. bostrychophila populations that can survive at 1 mg/L and 25°C over the same exposure period. Findings from our study will be used to formulate recommendations for registered dosage rates and fumigation periods for use in Australia.

Developments in phosphine resistance in China and possible implications for Australia

Resistance to phosphine was characterised in strains of rice weevil, Sirophilus oryzae, and the psocids Liposcelis entomophila and L. decolor from China and Australia. Mixed-age cultures (containing all life stages) of insects were tested using a flow-through apparatus. The criterion of response was 'time to population extinction' defined as the exposure period, in days, at which 100% mortality of adults and no live progeny were achieved. Chinese S. oryzae took 11 and 7 days for population extinction at 200 and 700 ppm phosphine, respectively, compared with the Australian strain, which was controlled in 7 and 5 days, respectively. Similarly, the Chinese strains L. Enfornophila and L. decolor were generally more difficult to control than the corresponding Australian strains. The Chinese strains of L. decolor showed resistance levels stronger than any grain storage insect pest species so far detected in Australia. This research allows us to evaluate the likely significance of potential new resistance to the Australian grain industry and to prepare effective fumigation dosages and resistance management strategies to combat new strong resistances before they emerge here.

Recovery and succession in a multi-species tropical seagrass meadow following experimental disturbance: the role of sexual and asexual reproduction

Recolonisation and succession in a multi-species tropical seagrass meadow was examined by creating gaps (50×50 cm) in the meadow and manipulating the supply of sexual and asexual propagules. Measurements of leaf shoot density and estimates of above-ground biomass were conducted monthly to measure recovery of gaps between September 1995 and November 1997. Measurements of the seeds stored in the sediment (seed bank) and horizontal rhizome growth of colonising species were also conducted to determine their role in the recovery process. Asexual colonisation through horizontal rhizome growth from the surrounding meadow was the main mechanism for colonisation of gaps created in the meadow. The seed bank played no role in recolonisation of cleared plots. Total shoot density and above-ground biomass (all species pooled) of cleared plots recovered asexually to the level of the undisturbed controls in 10 and 7 months, respectively. There was some sexual recruitment into cleared plots where asexual colonisation was prevented but seagrass abundance (shoot density and biomass) did not reach the level of unmanipulated controls. Seagrass species did not appear to form seed banks despite some species being capable of producing long-lived seeds. The species composition of cleared plots remained different to the undisturbed controls throughout the 26-month experiment. Syringodium isoetifolium was a rapid asexual coloniser of disturbed plots and remained at higher abundances than in the control treatments for the duration of the study. S. isoetifolium had the fastest horizontal rhizome growth of species asexually colonising cleared plots (6.9 mm day−1). Halophila ovalis was the most successful sexual coloniser but was displaced by asexually colonising species. H. ovalis was the only species observed to produce fruits during the study. Small disturbances in the meadow led to long-term (>2 years) changes in community composition. This study demonstrated that succession in tropical seagrass communities was not a deterministic process. Variations in recovery observed for different tropical seagrass communities highlighted the importance of understanding life history characteristics of species within individual communities to effectively predict their response to disturbance. A reproductive strategy involving clonal growth and production of long-lived, locally dispersed seeds is suggested which may provide an evolutionary advantage to plants growing in tropical environments subject to temporally unpredictable major disturbances such as cyclones

Homologues of the maize rust resistance gene Rp1-D are genetically associated with a major rust resistance QTL in sorghum

As part of a comparative mapping study between sugarcane and sorghum, a sugarcane cDNA clone with homology to the maize Rp1-D rust resistance gene was mapped in sorghum. The cDNA probe hybridised to multiple loci, including one on sorghum linkage group (LG) E in a region where a major rust resistance QTL had been previously mapped. Partial sorghum Rp1-D homologues were isolated from genomic DNA of rust-resistant and -susceptible progeny selected from a sorghum mapping population. Sequencing of the Rp1-D homologues revealed five discrete sequence classes: three from resistant progeny and two from susceptible progeny. PCR primers specific to each sequence class were used to amplify products from the progeny and confirmed that the five sequence classes mapped to the same locus on LG E. Cluster analysis of these sorghum sequences and available sugarcane, maize and sorghum Rp1-D homologue sequences showed that the maize Rp1-D sequence and the partial sugarcane Rp1-D homologue were clustered with one of the sorghum resistant progeny sequence classes, while previously published sorghum Rp1-D homologue sequences clustered with the susceptible progeny sequence classes. Full-length sequence information was obtained for one member of a resistant progeny sequence class ( Rp1-SO) and compared with the maize Rp1-D sequence and a previously identified sorghum Rp1 homologue ( Rph1-2). There was considerable similarity between the two sorghum sequences and less similarity between the sorghum and maize sequences. These results suggest a conservation of function and gene sequence homology at the Rp1 loci of maize and sorghum and provide a basis for convenient PCR-based screening tools for putative rust resistance alleles in sorghum.

Internationalizing school curriculum in Australasia: As niche, by test, or at heart?

Global citizenship has emerged as a pressing curricular priority which all educational systems are currently grappling with. The challenge is to negotiate how this orientation might sit alongside the more traditional mission of mass school curriculum in building collective ballast for a national identity through a common morality and shared narratives, or may conflict with efforts to protect and promote indigenous and minority identities. As a case study of how these agendas interact, this chapter will consider curricular responses to global imperatives in the variegated conditions across the Australasian region (defined as Australia, New Zealand and Papua New Guinea). The chapter will outline recent developments in the social, economic and political contexts surrounding curricular reforms in these settings, and demonstrate how these developments have changed the conditions of possibility and strength of purpose behind efforts to internationalise school curricula. Three types of systemic responses are then described: firstly, an appetite for globally branded curricula such as the International Baccalaureate, Montessori, and Cambridge University Certificates to distinguish some in a stratified market; secondly, convergence in curriculum to improve national performance on international standardised tests; and thirdly, the infusion of cosmopolitan sensibilities, regional identities and intercultural competencies as a core curricular goal for all. The chapter considers the various pragmatic interpretations of ‘internationalisation’ in these responses, and argues that the third response seems both the most difficult to enact, and the most vulnerable to political interference.

Effective Use in Livestock Feeds of Mouldy and Weather-damaged Grain Containing Mycotoxins-Case Histories and Economic Assessments Pertaining to Pig and Poultry Industries of Queensland

Mould growth in field crops or stored grain reduces starch and lipid content, with consequent increases in fibre, and an overall reduction in digestible energy; palatability is often adversely affected. If these factors are allowed for, and mycotoxin concentrations are low, there are sound economic reasons for using this cheaper grain. Mycotoxins are common in stock feed but their effects on animal productivity are usually slight because either the concentration is too low or the animal is tolerant to the toxin. In Australia, aflatoxins occur in peanut by-products and in maize and sorghum if the grain is moist when stored. Zearalenone is found in maize and in sorghum and wheat in wetter regions. Nivalenol and deoxynivalenol are found in maize and wheat but at concentrations that rarely affect pigs, with chickens and cattle being even more tolerant. Other mycotoxins including cyclopiazonic acid, T-2 toxin, cytochalasins and tenuazonic acid are produced by Australian fungi in culture but are not found to be significant grain contaminants. Extremely mouldy sorghum containing Alternaria and Fusarium mycotoxins decreased feed conversion in pigs and chickens by up to 14%. However, E moniliforme- and Diplodia maydis-infected maize produced only slight reductions in feed intake by pigs and Ustilago- infected barley produced no ill effects. Use of these grains would substantially increase profits if the grain can be purchased cheaply.

Mycotoxins and Fungal Damage in Maize Harvested during 1982 in Far North Queensland

A survey for mycotoxins and fungal damage in maize (Zea mays L.) grown during 1982 in Far North Queensland is reported. This season had a rainfall distribution which was typical for the reglon. The 293 samples examined came from 11 1 farms in eight maize-growing districts. The samples were first subjected to rapid screening tests for fungal damage. Aflatoxins B1, B2, G1, G2 ochratoxin A, T-2 toxin, and sterigmatocystin were not detected, but zearalenone was found in 85% of the samples. The concentrations of zearalenone were correlated with the extent of Gibberella zeae cob rot as indicated by the proportion (up to 2%) of kernels in each sample having a reddish-purple discoloration. In four samples the zearalenone concentration exceeded 1 mg kg-1, but the mean ¦ s.d. (n = 293) concentration in all samples was 0.17 ¦ 0.225 mg kg-1. Concentrations were highest in districts with the highest rainfall during the period of maize growth.

Effects of severity of threshing damage on seed quality of Gatton panic Panicum maximum)

Different degrees of severity of threshing were imposed during combine-harvesting of seed of Gatton panic, a cultivar of Panicum maximum , to determine effects of degree of threshing damage on subsequent properties of seed. Threshing cylinder peripheral speeds and concave clearances covering the normal range employed commercially were varied experimentally in the harvest of 2 crops grown in north Queensland. Harvested seed was dried and cleaned, then stored under ambient conditions. The extent of physical damage was measured, and samples were tested at intervals for viability, germination, dormancy and seedling emergence from soil in a glasshouse and in the field over the 2 seasons following harvest. Physical damage increased as peripheral rotor speed rose and (though less markedly) as concave clearance was reduced. As the level of damage increased, viability was progressively reduced, life expectancy was shortened, and dormancy was broken. When the consequences were measured as seedling emergence from soil, the adverse effects on viability tended to cancel out the benefits of dormancy-breaking, leaving few net differences attributable to the degree of threshing severity. We concluded that there would be no value in trying to manipulate the quality of seed produced for normal commercial use through choice of cylinder settings, but that deliberate light or heavy threshing could benefit special-purpose seed, destined, respectively, for long-term storage or immediate use.

Predicting survival of western rock lobsters Panulirus cygnus using discriminant analysis of hemolymph parameters taken immediately following simulated handling treatments

Instances of morbidity amongst rock lobsters (Panulirus cygnus) arriving at factories in Western Australia (WA) have been attributed to stress during post-harvest handling. This study used discriminant analysis to determine whether physiological correlates of stress following a period of simulated post-harvest handling had any validity as predictors of future rejection or morbidity of western rock lobsters. Groups of 230 western rock lobsters were stored for 6 h in five environments (submerged/flowing sea water, submerged/re-circulating sea water, humid air, flowing sea water spray, and re-circulated sea water spray). The experiment was conducted in late spring (ambient sea water 22°C), and repeated again in early autumn (ambient sea water 26°C). After 6 h treatment, each lobster was graded for acceptability for live export, numbered, and its hemolymph was sampled. The samples were analysed for a number of physiological and health status parameters. The lobsters were then stored for a week in tanks in the live lobster factory to record mortality. The mortality of lobsters in the factory was associated with earlier deviations in hemolymph parameters as they emerged from the storage treatments. Discriminant analysis (DA) of the hemolymph assays enabled the fate of 80-90% of the lobsters to be correctly categorised within each experiment. However, functions derived from one experiment were less accurate at predicting mortality when applied to the other experiments. One of the reasons for this was the higher mortality and the more severe patho-physiological changes observed in lobsters stored in humid air or sprays at the higher temperature. The analysis identified lactate accumulation during emersion and associated physiological and hemocyte-related effects as a major correlate of mortality. Reducing these deviations, for example by submerged transport, is expected to ensure high levels of survival. None of the indicators tested predicted mortality with total accuracy. The simplest and most accurate means of comparing emersed treatments was to count the mortality afterwards.

Host range, symptom expression and RNA 3 sequence analyses of six Australian strains of Cucumber mosaic virus

We have characterised six Australian Cucumber mosaic virus (CMV) strains belonging to different subgroups, determined by the sequence of their complete RNA 3 and by their host range and the symptoms they cause on species in the Solanaceae, Cucurbitaceae and on sweet corn. These data allowed classification of strains into the known three CMV subgroups and identification of plant species able to differentiate the Australian strains by symptoms and host range. Western Australian strains 237 and Twa and Queensland strains 207 and 242 are closely related members of CMV subgroup IA, which cause similar severe symptoms on Nicotiana species. Strains 207 and 237 (subgroup IA) were the only strains tested which systemically infected sweet corn. Strain 243 caused the most severe symptoms of all strains on Nicotiana species, tomato and capsicum and appears to be the first confirmed subgroup IB strain reported in Australia. Based on pair-wise distance analysis and phylogeny of RNA 3, as well as mild disease symptoms on Nicotiana species, CMV 241 was assigned to subgroup II, as the previously described Q-CMV and LY-CMV.

The storage stability of passionfruit concentrate

Passionfruit (Passiflora edulis) concentrates (542 g/kg soluble solids) prepared in a wiped-film evaporator were stored for up to 6 months at - 18°, 4° and 20°C. Yeast and mould counts were taken and colour changes noted during storage. When suitable diluted concentrate colour and flavour were acceptable for 1 month at 20°C, 3 months at 4°C and 6 months at -18°C. Commercial short-term storage of concentrate at temperatures above -18°C appears to be feasible. An address presented to the 20th Annual Convention AIFST, Albury NSW, 16th- 20th May, 1987

Storage of Macadamia Nut-In-Shell

The effect of moisture content and storage temperature on the high quality storage life on macadamia nut-in-shell (NIS), and the subsequent influence of NIS storage on the shelf-life of roasted kernel, is being investigated. Macadamia integrifolia 'Keauhou" (HAES 246) NIS is being stored at 5°, 25°C and 40°C with a moisture content of 15.0, 12.5, 10.0, 7.5 and 3.5% for a maximum of 12 months. Preliminary results showed that unacceptable levels of visual mould developed on NIS with 15.0 and 12.5% moisture at 25°C following relatively short periods of storage. Discolouration and the production of an off-flavour in the raw kernel resulted after 1 month's storage of NIS with a moisture content of 10.0% at 40°C. Roasting times were reduced with increased storage duration of NIS with a moisture content of 15.0, 12.5 and 10.0% at 25°C, 15.0 and 12.5% at 5°C and 3.5% at 40°C. The percentage of roasted kernel rejects increased with increased storage duration of NIS with a moisture content of 15.0 and 12.5% at 25°C.

Population ecology of Heteronyx piceus (Coleoptera: Scarabaeidae) in a peanut/maize cropping system

Large larval populations of the scarabaeid beetle Heteronyx piceus Blanchard that occur under peanuts, but not maize, in the South Burnett region of Australia are the result of a high rate and prolonged period of egg production by females feeding on peanut foliage. Heteronyx piceus is a relatively sedentary species and movement of females between adjacent fields is low. Populations of H. piceus varied markedly with landscape position. High larval populations are more likely (1 in 4 chance) to be encountered on the ‘scrub’ soils in the upper parts of the landscape than in the ‘forest’ soils in the lower half (1 in 20 chance), indicating that soil type/landscape position is a key risk factor in assessing the need for management intervention. The studies indicate that, because of the species' sedentary nature, the most meaningful population entity for management of H. piceus is the individual field, rather than the whole-farm or the region. The implications of this population ecology for management of the pest are discussed in relation to control strategies.

Impact of cold storage on glucosinolate levels in seed-sprouts of broccoli, rocket, white radish and kohl-rabi

The effect of cold storage on glucosinolate concentration was examined in 7-day-old seed-sprouts of broccoli, kohl rabi, white radish and rocket. Principal glucosinolates identified were glucoraphanin and glucoerucin (in broccoli, kohl rabi and rocket), glucoiberin (in broccoli and kohl rabi), and glucoraphenin and glucodehydroerucin (in white radish). Generally, sprouts showed no significant changes in individual glucosinolate concentrations during storage at 4°C for 3 weeks. The exception to this was rocket, which showed a significant decline in glucoerucin and glucoraphanin after 1 and 2 weeks, respectively. These preliminary results indicate that as there is no significant loss of glucosinolates in broccoli, radish and kohl rabi sprouts, these sprouts may be stored under domestic refrigeration conditions without significant loss of potential anti-cancer compounds. Rocket sprouts, on the other hand, should be consumed soon after purchase if glucosinolate levels are to be maintained.

Assessing the relationship between shire winter crop yield and seasonal variability of the MODIS NDVI and EVI images

Australian researchers have been developing robust yield estimation models, based mainly on the crop growth response to water availability during the crop season. However, knowledge of spatial distribution of yields within and across the production regions can be improved by the use of remote sensing techniques. Images of Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation indices, available since 1999, have the potential to contribute to crop yield estimation. The objective of this study was to analyse the relationship between winter crop yields and the spectral information available in MODIS vegetation index images at the shire level. The study was carried out in the Jondaryan and Pittsworth shires, Queensland , Australia . Five years (2000 to 2004) of 250m resolution, 16-day composite of MODIS Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) images were used during the winter crop season (April to November). Seasonal variability of the profiles of the vegetation index images for each crop season using different regions of interest (cropping mask) were displayed and analysed. Correlation analysis between wheat and barley yield data and MODIS image values were also conducted. The results showed high seasonal variability in the NDVI and EVI profiles, and the EVI values were consistently lower than those of the NDVI. The highest image values were observed in 2003 (in contrast to 2004), and were associated with rainfall amount and distribution. The seasonal variability of the profiles was similar in both shires, with minimum values in June and maximum values at the end of August. NDVI and EVI images showed sensitivity to seasonal variability of the vegetation and exhibited good association (e.g. r = 0.84, r = 0.77) with winter crop yields.