Historical demography of Lantana camara L. reveals clues about the influence of land use and weather in the management of this widespread invasive species

Weather is a general stochastic influence on the life history of weeds. In contrast, anthropogenic disturbance (e.g. land use) is an important deterministic influence on weed demography. Our aim with this study was to investigate the relative contributions of land use and weather on the demography of Lantana camara (lantana), a weed of agricultural and natural habitats, based on the intensive monitoring of lantana populations under three land uses (viz. farm[pasture], and burnt and grazed forests) in subtropical Australia. Lantana populations were growing vigorously across all land uses (asymptotic population growth rate, λ > 3). Examination of historical demography using retrospective perturbation analyses showed that weather was a strong influence on lantana demography with the transition from an El Niño (2008–09) to a La Niña (2009–10) year having a strong positive effect on population growth rate. This effect was most marked at the grazed site, and to a lesser extent at the burnt site, with seedling-to-juvenile and juvenile-to-adult transitions contributing most to these effects. This is likely the result of burning and grazing having eliminated/reduced interspecific competition at these sites. Prospective perturbation analyses revealed that λ was most sensitive to proportionate changes in growth transitions, followed by fecundity and survival transitions. Examination of context-specific patterns in elasticity revealed that growth and fecundity transitions are likely to be the more critical vital rates to reduce λ in wet years at the burnt and grazed forest sites, compared to the farm/pasture site. Management of lantana may need to limit the transition of juveniles into the adult stages, especially in sites where lantana is free from competition (e.g. in the presence of fire or grazing), and this particularly needs to be achieved in wet years. Collectively, these results shed light on aspects of spatial and temporal variation in the demography of lantana, and offer insights on its context-specific management.

Bactrocera frauenfeldi (Diptera: Tephritidae), an invasive fruit fly in Australia that may have reached the extent of its spread due to environmental variables

Bactrocera frauenfeldi (Schiner), the ‘mango fruit fly’, is a horticultural pest originating from the Papua New Guinea region. It was first detected in Australia on Cape York Peninsula in north Queensland in 1974 and had spread to Cairns by 1994 and Townsville by 1997. Bactrocera frauenfeldi has not been recorded further south since then despite its invasive potential, an absence of any controls and an abundance of hosts in southern areas. Analysis of cue-lure trapping data from 1997 to 2012 in relation to environmental variables shows that the distribution of B. frauenfeldi in Queensland correlates to locations with a minimum temperature for the coldest month >13.2°C, annual temperature range <19.3°C, mean temperature of the driest quarter >20.2°C, precipitation of the wettest month >268 mm, precipitation of the wettest quarter >697 mm, temperature seasonality <30.9°C (i.e. lower temperature variability) and areas with higher human population per square kilometre. Annual temperature range was the most important variable in predicting this species' distribution. Predictive distribution maps based on an uncorrelated subset of these variables reasonably reflected the current distribution of this species in northern Australia and predicted other areas in the world potentially at risk from invasion by this species. This analysis shows that the distribution of B. frauenfeldi in Australia is correlated to certain environmental variables that have most likely limited this species' spread southward in Queensland. This is of importance to Australian horticulture in demonstrating that B. frauenfeldi is unlikely to establish in horticultural production areas further south than Townsville.

The grand challenge of food security - general lessons from a comprehensive approach to protecting stored grain from insect pests in Australia and India

We outline a philosophical approach to Grand Challenge projects, with particular reference to our experience in our food security project involving the protection of stored grain from insect attack in two countries on different continents. A key consideration throughout has been the management of resistance in these pests to the valuable fumigant phosphine. Emphasis is given to the chain of research issues that required solution and the assembly of a well-integrated team, overlapping in skills for effective communication, in each country to solve the problems identified along that chain. A crucial aspect to maintaining direction is the inclusion of key end users in all deliberations, as well as the establishment and maintenance of effective outlets for the dissemination of practical recommendations. We finish with a summary of our achievements with respect to our approach to this food security Grand Challenge.

Soybean Stem Fly, Melanagromyza sojae (Diptera: Agromyzidae), in the New World: detection of high genetic diversity from soybean fields in Brazil

Soybean Stem Fly (SSF), Melanagromyza sojae (Zehntner), belongs to the family Agromyzidae and is highly polyphagous, attacking many plant species of the family Fabaceae, including soybean and other beans. SSF is regarded as one of the most important pests in soybean fields of Asia (e.g., China, India), North East Africa (e.g., Egypt), parts of Russia, and South East Asia. Despite reports of Agromyzidae flies infesting soybean fields in Rio Grande do Sul State (Brazil) in 1983 and 2009 and periodic interceptions of SSF since the 1940s by the USA quarantine authorities, SSF has not been officially reported to have successfully established in the North and South Americas. In South America, M. sojae was recently confirmed using morphology and its complete mitochondrial DNA (mtDNA) was characterized. In the present study, we surveyed the genetic diversity of M. sojae, collected directly from soybean host plants, using partial mtDNA cytochrome oxidase I (COI) gene, and provide evidence of multiple (>10) maternal lineages in SSF populations in South America, potentially representing multiple incursion events. However, a single incursion involving multiple-female founders could not be ruled out. We identified a haplotype that was common in the fields of two Brazilian states and the individuals collected from Australia in 2013. The implications of SSF incursions in southern Brazil are discussed in relation to the current soybean agricultural practices, highlighting an urgent need for better understanding of SSF population movements in the New World, which is necessary for developing effective management options for this significant soybean pest. © FUNPEC-RP.

Accumulation, persistence and effects of indospicine residues in camels fed Indigofera plant

Indospicine (L-2-amino-6-amidinohexanoic acid) is a natural hepatotoxin found in all parts of some Indigofera plants such as I. linnaei and I. spicata. Several studies have documented a susceptibility to this hepatotoxin in different species of animals, including cattle, sheep, dogs and rats, which are associated with mild to severe liver disease after prolonged ingestion. However, there is little published data on the effects of this hepatotoxin in camels, even though Indigofera plants are known to be palatable to camels in central Australia. The secondary poisoning of dogs after prolonged dietary exposure to residual indospicine in camel muscle has raised additional food safety concerns. In this study, a feeding experiment was conducted to investigate the in vivo accumulation, excretion, distribution and histopathological effects of dietary indospicine on camels. Six young camels (2 – 4 year old), weighing 270 − 390 kg were fed daily a roughage diet consisting of Rhodes grass hay and lucerne chaff, supplemented with Indigofera and steam flaked barley. Indigofera (I. spicata) was offered at 597 mg DM/kg body weight (bw)/day designed to deliver 337 µg indospicine/kg bw/day, and fed for a period of 32 days. Blood and muscle biopsies were collected over the period of the study. Concentrations of indospicine in the plasma and muscle biopsy samples were quantitated by validated ultra-performance liquid chromatography−tandem mass spectrometry (UPLC−MS/MS). The highest concentrations in plasma (1.01 mg/L) and muscle (2.63 mg/kg fresh weight (fw)) were found at necropsy (day 33). Other tissues were also collected at necropsy and analysis showed ubiquitous distribution of indospicine, with the highest indospicine accumulation detected in the pancreas (4.86 ± 0.56 mg/kg fw) and liver (3.60 ± 1.34 mg/kg fw); followed by the muscle, heart and kidney. Histopathological examination of liver tissue showed multiple small foci of predominantly mononuclear inflammatory cells. After cessation of Indigofera intake, indospicine present in plasma in the remaining 3 camels had a longer terminal elimination half-life (18.6 days) than muscle (15.9 days), and both demonstrated mono-exponential decreases.

Seasonal and Species Variation of the Hepatotoxin Indospicine in Australian Indigofera Legumes as Measured by UPLC−MS/MS

Livestock industries have maintained a keen interest in pasture legumes because of the high protein content and nutritive value. Leguminous Indigofera plant species have been considered as having high feeding values to be utilized as pasture, but the occurrence of the toxic constituent indospicine in some species has restricted this utility. Indospicine has caused both primary and secondary hepatotoxicosis and also reproductive losses, but has only previously been determined in a small number of Indigofera species. This paper validates a high throughput ultra-performance liquid chromatography−tandem mass spectrometry (UPLC−MS/MS) method to determine indospicine content of various Indigofera species found in Australian pasture. Twelve species of Indigofera together with Indigastrum parviflorum plants were collected and analysed. Out of the 84 samples analyzed, *I. spicata contained the highest indospicine level (1003 ± 328 mg/kg DM, n = 4) followed by I. linnaei (755 ± 490 mg/kg DM, n = 51). Indospicine was not detected in 9 of the remaining 11 species, and at only low levels (<10 mg/kg DM) in 2 out of 8 I. colutea specimens and in 1 out of 5 I. linifolia specimens. Indospicine concentrations were below quantitation levels for other Indigofera spp. (I. adesmiifolia, I. georgei, I. hirsuta, I. leucotricha,* I. oblongifolia, I. australis and I. trita) and Indigastrum parviflorum. One of the more significant findings to emerge from this study is that the indospicine content of I. linnaei is highly variable (159 to 2128 mg/kg DM, n = 51), and differs across both regions and seasons. Its first re-growth after spring rain has a higher (p < 0.01) indospicine content than growth following more substantial summer rain. The species collected include the predominant Indigofera in Australia pasture, and of these, only *I. spicata and I. linnaei contain high enough levels of indospicine to pose a potential toxic threat to grazing herbivores.

Investigation into various fungicides and alternative solutions for controlling postharvest diseases in papaya fruit

In Australia, Sportak® (a.i., prochloraz) has been registered since the early 1980's for the postharvest control of both anthracnose and stem-end rots in papaya fruit, despite the persistence of fruit breakdown due to disease during transit and at market destinations. Consequently, the Australian papaya industry has been concerned over the efficacy of prochloraz and whether substitute or alternative solutions were available for better disease control, particularly during times of peak disease pressure. This study therefore investigated the effects of various postharvest treatments for disease control in papaya. Fruit were harvested at colour break from coastal farms in Far North Queensland and treated with commercial rates of various fungicides, including prochloraz, imazalil, thiabendazole and fludioxonil. Additional solutions known to inhibit disease were examined, including chitosan and carnauba wax both with and without ammonium carbonate (AC). Following treatment, fruit were ripened and assessed for quality over their shelf life. Fludioxonil when applied as a hot dip was found to be a more efficacious treatment for control of disease in papaya than prochloraz. The other fungicides were moderately effective, as both thiabendazol and prochloraz exhibited an intermediate response and imazalil was the least effective. Disease severity was lowest in fruit treated with AC followed by chitosan, whilst chitosan delayed degreening. Overall, the study found that hot fludioxonil provided an effective replacement of the currently registered chemical prochloraz, and that alternate solutions such chitosan and AC may also be beneficial, particularly for low chemical input farming systems.

Control of grey mould and stem-end rot in strawberry plants growing in a subtropical environment

The effect of different fungicide programs on grey mould (caused by Botrytis cinerea) and stem-end rot (caused by Gnomoniopsis fructicola) affecting strawberry plants (Fragaria ×ananassa cv. Festival) was studied in subtropical Australia over three years. The treatments involved a range of different synthetic multi- and single-site fungicides with different modes of action, a plant-defence promoter, plant extracts (lupin and rhubarb), organic acids, fatty acids, a salt, two strains of Bacillus subtilis, and single strains of B. amyloliquefaciens, Streptomyces lydicus and Trichoderma harzianum. Standard programs based on captan and thiram alternated, and applied with iprodione, fenhexamid, cyprodinil + fludioxonil, and penthiopyrad resulted in 3–4 % of unmarketable fruit compared with 25–38 % in the water-treated controls. There was no difference in the level of disease suppression when five or thirteen applications of single-site fungicides were rotated with the two multi-site fungicides. The incidence of unmarketable fruit was similar to the standard programs using isopyrazam (in 1 year out of 2), or penthiopyrad, fluazinam, chlorothalonil or thiram alone (in 1 year out of 1). The other fungicide programs were generally less effective. There were strong relationships between marketable yield and the incidence of unmarketable fruit over the three years (R2s = 0.82–0.93). A strategy based on thiram and captan applied alternately, with reduced applications of single-site fungicides is recommended and should reduce the chance of resistance to single-site fungicides becoming widespread in populations of the grey mould fungus. Although the program based on thiram alone had a similar incidence of unmarketable fruit as the standard program, repeated weekly applications of thiram are not recommended as they may cause unacceptable residues in the fruit. There were issues with some of the other fungicides due to phytotoxicity, residues, or difficulties with registering new fungicides that are in the same chemical group as currently registered products.

Lepidopterous Pests Of The Litchi In North Queensland

A list is given of 34 species of Lepidoptera feeding on litchi in northern Queensland, including notes on type of damage and months of activity. Records from outside of Australia are also reviewed.

Risk management strategies using seasonal climate forecasting in irrigated cotton production: a tale of stochastic dominance.

Decision-making in agriculture is carried out in an uncertain environment with farmers often seeking information to reduce risk. As a result of the extreme variability of rainfall and stream-flows in north-eastern Australia, water supplies for irrigated agriculture are a limiting factor and a source of risk. The present study examined the use of seasonal climate forecasting (SCF) when calculating planting areas for irrigated cotton in the northern Murray Darling Basin. Results show that minimising risk by adjusting plant areas in response to SCF can lead to significant gains in gross margin returns. However, how farmers respond to SCF is dependent on several other factors including irrigators’ attitude towards risk.

A sampling technique for two-spotted mite in papaya

Two-spotted mite, Tetranychus urticae Koch, was until recently regarded as a minor and infrequent pest of papaya in Queensland through the dry late winter/early summer months. The situation has changed over the past 4-5 years, so that now some growers consider spider mites significant pests all year round. This altered pest status corresponded with a substantial increase in the use of fungicides to control black spot (Asperisporium caricae). A project was initiated in 1998 to examine the potential reasons for escalating mite problems in commercially-grown papaya, which included regular sampling over a 2 year period for mites, mite damage and beneficial arthropods on a number of farms on the wet tropical coast and drier Atherton Tableland. Differences in soil type, papaya variety, chemical use and some agronomic practices were included in this assessment. Monthly visits were made to each site where 20 randomly-selected plants from each of 2 papaya lines (yellow and red types) were surveyed. Three leaves were selected from each plant, one from each of the bottom, middle and top strata of leaves. The numbers of mobile predators were recorded, along with visual estimates of the percentage and age of mite damage on each leaf. Leaves were then sprayed with hairspray to fix the mites and immature predators to the leaf surface. Four leaf disks, 25 mm in diameter, were then punched from each leaf into a 50 ml storage container with a purpose-built disk-cutting tool. Disks from each leaf position were separated by tissue paper, within the container. On return to the laboratory, each leaf disk was scrutinised under a binocular microscope to determine the numbers of two-spotted mites and eggs, predatory mites and eggs, and the immature stages of predatory insects (mainly Stethorus, Halmus and lacewings). A total of 2160 leaf disks have been examined each month. All data have been entered into an Access database to facilitate comparisons between sites.

Simulation of the supply capability of sheep on the Mitchell grass downs of north west Queensland

Sheep in western Queensland have been predominantly reared for wool. When wool prices became depressed interest in the sheep meat industry, increased. For north west Queensland producers, opportunities may exist to participate in live sheep and meat export to Asia. A simulation model was developed to determine whether this sheep producing area has the capability to provide sufficient numbers of sheep under variable climatic conditions while sustaining the land resources. Maximum capacity for sustainability of resources (as described by stock numbers) was derived from an in-depth study of the agricultural and pastoral potential of Queensland. Decades of sheep production and climatic data spanning differing seasonal conditions were collated for analysis. A ruminant biology model adapted from Grazplan was used to simulate pregnancy rate. Empirical equations predict mortalities, marking rates, and weight characteristics of sheep of various ages from simple climatic measures, stocking rate and reproductive status. The initial age structure of flocks was determined by running the model for several years with historical climatic conditions. Drought management strategies such as selling a proportion of wethers progressively down to two-tooth and oldest ewes were incorporated. Management decisions such as time of joining, age at which ewes were cast-for-age, wether turn-off age and turning-off rate of lambs vary with geographical area and can be specified at run time. The model is run for sequences of climatic conditions generated stochastically from distributions based on historical climatic data correlated in some instances. The model highlights the difficulties of sustaining a consistent supply of sheep under variable climatic conditions.

Improved Approach for Analyzing Bromophenols in Seafood Using Stable Isotope Dilution Analysis in Combination with SPME

An analytical method for the measurement of five naturally occurring bromophenols of sensory relevance in seafood (barramundi and prawns) is presented. The method combines simultaneous distillation−extraction followed by alkaline back extraction of a hexane extract and subsequent acetylation of the bromophenols. Analysis of the bromophenol acetates was accomplished by headspace solid phase microextraction and gas chromatography−mass spectrometry using selected ion monitoring. The addition of 13C6 bromophenol stable isotope internal standards for each of the five congeners studied permitted the accurate quantitation of 2-bromophenol, 4-bromophenol, 2,6-dibromophenol, 2,4-dibromophenol, and 2,4,6-tribromophenol down to a limit of quantification of 0.05 ng/g of fish flesh. The method indicated acceptable precision and repeatability and excellent linearity over the typical concentration range of these compounds in seafood (0.5−50 ng/g). The analytical method was applied to determine the concentration of bromophenols in a range of farmed and wild barramundi and prawns and was also used to monitor bromophenol uptake in a pilot feeding trial.

Development of hazard site surveillance programs for forest invasive species: A case study from Brisbane, Australia

Hazard site surveillance is a system for post-border detection of new pest incursions, targeting sites that are considered potentially at high risk of such introductions. Globalisation, increased volumes of containerised freight and competition for space at domestic ports means that goods are increasingly being first opened at premises some distance from the port of entry, thus dispersing risk away from the main inspection point. Hazard site surveillance acts as a backstop to border control to ensure that new incursions are detected sufficiently early to allow the full range of management options, including eradication and containment, to be considered. This is particularly important for some of the more cryptic forest pests whose presence in a forest often is not discovered until populations are already high and the pest is well established. General requirements for a hazard site surveillance program are discussed using a program developed in Brisbane, Australia, in 2006 as a case study. Some early results from the Brisbane program are presented. In total 67 species and 5757 individuals of wood-boring beetles have been trapped and identified during the program to date. Scolytines are the most abundant taxa, making up 83% of the catch. No new exotics have been trapped but 19 of the species and 60% of all specimens caught are exotics that are already established in Australia.

Hardness Methods for Testing Maize Kernels

Maize is a highly important crop to many countries around the world, through the sale of the maize crop to domestic processors and subsequent production of maize products and also provides a staple food to subsistance farms in undeveloped countries. In many countries, there have been long-term research efforts to develop a suitable hardness method that could assist the maize industry in improving efficiency in processing as well as possibly providing a quality specification for maize growers, which could attract a premium. This paper focuses specifically on hardness and reviews a number of methodologies as well as important biochemical aspects of maize that contribute to maize hardness used internationally. Numerous foods are produced from maize, and hardness has been described as having an impact on food quality. However, the basis of hardness and measurement of hardness are very general and would apply to any use of maize from any country. From the published literature, it would appear that one of the simpler methods used to measure hardness is a grinding step followed by a sieving step, using multiple sieve sizes. This would allow the range in hardness within a sample as well as average particle size and/or coarse/fine ratio to be calculated. Any of these parameters could easily be used as reference values for the development of near-infrared (NIR) spectroscopy calibrations. The development of precise NIR calibrations will provide an excellent tool for breeders, handlers, and processors to deliver specific cultivars in the case of growers and bulk loads in the case of handlers, thereby ensuring the most efficient use of maize by domestic and international processors. This paper also considers previous research describing the biochemical aspects of maize that have been related to maize hardness. Both starch and protein affect hardness, with most research focusing on the storage proteins (zeins). Both the content and composition of the zein fractions affect hardness. Genotypes and growing environment influence the final protein and starch content and. to a lesser extent, composition. However, hardness is a highly heritable trait and, hence, when a desirable level of hardness is finally agreed upon, the breeders will quickly be able to produce material with the hardness levels required by the industry.