Bitou bush and boneseed eradication and containment in Australia

Bitou bush and boneseed (Chrysanthemoides monilifera subsp. rotundata (DC.) T.Norl. and C. monilifera subsp. monilifera (L.) T.Norl., respectively) are highly invasive environmental weeds that pose a serious threat to Australia’s natural ecosystems and biota. Bitou bush threatens coastal plant communities in New South Wales (NSW), eastern Victoria and southeast Queensland (Qld), while boneseed threatens inland and coastal native plant communities across NSW, South Australia (SA), Tasmania, Victoria, and Western Australia (WA). Over 200 plant species and ecological communities in Australia are negatively impacted by these weeds (ARMCANZ et al. 2000, DEC 2006) and over 15% (approx. 120 million ha) of Australia is susceptible to invasion (see maps in Weiss et al 2008). In 2000, the National Bitou Bush and Boneseed Strategic Plan (ARMCANZ et al. 2000) was approved as part of the Commonwealth’s Weeds of National Significance initiative. A key goal of this plan is to prevent the spread of bitou bush and boneseed in Australia. A national program sponsored by the Australian Government and the affected states has resulted in the development of national containment and eradication zones that prevent the spread of bitou bush and boneseed. This paper presents an overview of these bitou bush and boneseed containment and eradication programs.

(Z)-11-Hexadecenal and (3Z,6Z,9Z)-Tricosatriene: Sex Pheromone Components of the Red Banded Mango Caterpillar Deanolis sublimbalis

The sex pheromone of the red banded mango caterpillar, Deanolis sublimbalis (Lepidoptera: Crambidae), a serious pest of the mango Mangifera indica (Anacardiaceae) in India and Southeast Asia and a recent invader into northern Australia, has been identified. Three candidate compounds were identified from pheromone gland extracts of female moths, using gas chromatography (GC), GC-electroantennographic detection and GC-mass spectrometric analyses, in conjunction with dimethyldisulfide derivatization. Field bioassays established that both (Z)-11-hexadecenal (Z11-16:Ald) and (3Z,6Z,9Z)-tricosatriene (3Z,6Z,9Z-23:Hy) were required for attraction of male D. sublimbalis moths, and 1,000 μg of a 1:1 mix of Z11-16:Ald and 3Z,6Z,9Z-23:Hy was more attractive to male moths than caged virgin females. However, the binary blend was only attractive when the isomeric purity of the monounsaturated aldehyde was >99%, suggesting that the (E)-isomer was inhibitory. Although (Z)-11-hexadecen-1-ol (Z11-16:OH) was tentatively identified in gland extracts, the addition of this compound to the binary blend did not increase the numbers of moths captured. The pheromone can now be used in integrated pest management strategies.

The genetic structure of Australasian green turtles (Chelonia mydas): Exploring the geographical scale of genetic exchange

Ecological and genetic studies of marine turtles generally support the hypothesis of natal homing, but leave open the question of the geographical scale of genetic exchange and the capacity of turtles to shift breeding sites. Here we combine analyses of mitochondrial DNA (mtDNA) variation and recapture data to assess the geographical scale of individual breeding populations and the distribution of such populations through Australasia. We conducted multiscale assessments of mtDNA variation among 714 samples from 27 green turtle rookeries and of adult female dispersal among nesting sites in eastern Australia. Many of these rookeries are on shelves that were flooded by rising sea levels less than 10 000 years (c. 450 generations) ago. Analyses of sequence variation among the mtDNA control region revealed 25 haplotypes, and their frequency distributions indicated 17 genetically distinct breeding stocks (Management Units) consisting either of individual rookeries or groups of rookeries in general that are separated by more than 500 km. The population structure inferred from mtDNA was consistent with the scale of movements observed in long-term mark-recapture studies of east Australian rookeries. Phylogenetic analysis of the haplotypes revealed five clades with significant partitioning of sequence diversity (Φ = 68.4) between Pacific Ocean and Southeast Asian/Indian Ocean rookeries. Isolation by distance was indicated for rookeries separated by up to 2000 km but explained only 12% of the genetic structure. The emerging general picture is one of dynamic population structure influenced by the capacity of females to relocate among proximal breeding sites, although this may be conditional on large population sizes as existed historically across this region.

Carotenoid content and flesh color of selected banana cultivars growing in Australia.

Background: The problems of vitamin A deficiency and chronic diseases have emerged in recent years in some countries in the Micronesian region. These problems are associated with the dietary shift towards imported processed foods and lifestyle changes. Research in the Federated States of Micronesia indicates that yellow- and orange-fleshed banana cultivars contain significant levels of provitamin A carotenoids. Objective: To identify further banana cultivars that may be promoted to alleviate vitamin A deficiency among children and women and chronic disease problems among adults. Methods: Ripe fruit of banana cultivars growing in Australia (sourced mostly from a field research collection) were assessed for carotenoid content and flesh color. Ten cultivars with yellow or yellow/orange flesh color (including common cultivars of Southeast Asia and the Pacific Islands) were selected and compared with two cream-fleshed cultivars, including Williams, of the Cavendish group, the most commonly marketed banana worldwide. Carotenoid content was analyzed by high-performance liquid chromatography (HPLC). Flesh color was analyzed by HunterLab colorimetry. Results: The yellow/orange-fleshed Asupina (a Fe'i banana) contained the highest level (1,412 μg/100 g) of trans β-carotene, the most important provitamin A carotenoid, a level more than 20 times higher than that of Williams. All 10 yellow or yellow/orange-fleshed cultivars (Asupina, Kirkirnan, Pisang Raja, Horn Plantain, Pacific Plantain, Kluai Khai Bonng, Wain, Red Dacca, Lakatan, and Sucrier) had significant carotenoid levels, potentially meeting half or all of the estimated vitamin A requirements for a nonpregnant, nonlactating adult woman within normal consumption patterns. All were acceptable for taste and other attributes. The cream-fleshed cultivars had minimal carotenoid levels. There was a positive significant correlation between carotenoid content and deeper yellow/orange coloration indicators. Conclusions: These yellow- or yellow/orange-fleshed carotenoid-rich banana cultivars should be considered for promotion in order to alleviate vitamin A deficiency and chronic disease in susceptible target communities and to provide variety and enjoyment as exotic fruits in both developing and industrialized countries.

Epitypification and phylogeny of Colletotrichum acutatum J.H. Simmonds

Simmonds introduced Colletotrichum acutatum in 1965, validated in 1968, with a broad concept, as demonstrated by the selection of several type specimens from a range of hosts. This has created some confusion in the species concept and identification of C. acutatum. There are no viable ex-type cultures of C. acutatum and furthermore there are no existing cultures of C. acutatum on Carica papaya from the type locality in south-east Queensland. The application of molecular phylogenetic studies to isolates of C. acutatum is only meaningful if the taxonomy is stable and species are properly named. In order to clarify the species concept of C. acutatum, an isolate of Colletotrichum acutatum from Carica papaya from Yandina in Southeast Queensland (Australia) is designated as an epitype. A detailed morphological description is provided. Phylogenies based on a combined ITS and beta-tubulin gene analysis indicate that C. acutatum bears close phylogenetic affinities to C. gloeosporioides and C. capsici. Results also indicate that C. acutatum is monophyletic and there is a close relationship between the epitype and other Australian C. acutatum isolates from Carica papaya. Molecular data, however did not provide further evidence to properly elucidate the taxonomie affinities of C. acutatum especially the holotype and epitype. Our studies indicate that given the complexity of the genus Colletotrichum, there is a need to check previously described type specimens and redesign neotypes where necessary in order to clarify taxonomie uncertainties.

Sorghum ergot can develop without local Claviceps africana inoculum from nearby infected plants

Batches of glasshouse-grown flowering sorghum plants were placed in circular plots for 24 h at two field sites in southeast Queensland, Australia on 38 occasions in 2003 and 2004, to trap aerial inoculum of Claviceps africana. Plants were located 20-200 m from the centre of the plots. Batches of sorghum plants with secondary conidia of C. africana on inoculated spikelets were placed at the centre of each plot on some dates as a local point source of inoculum. Plants exposed to field inoculum were returned to a glasshouse, incubated at near-100% relative humidity for 48 h and then at ambient relative humidity for another week before counting infected spikelets to estimate pathogen dispersal. Three times as many spikelets became infected when inoculum was present within 200 m of trap plants, but infected spikelets did not decline with increasing distance from local source within the 200 m. Spikelets also became infected on all 10 dates when plants were exposed without a local source of infected plants, indicating that infection can occur from conidia surviving in the atmosphere. In 2005, when trap plants were placed at 14 locations along a 280 km route, infected spikelets diminished with increasing distance from sorghum paddocks and infection was sporadic for distances over 1 km. Multiple regression analysis showed significant influence of moisture related weather variables on inoculum dispersal. Results suggest that sanitation measures can help reduce ergot severity at the local level, but sustainable management will require better understanding of long-distance dispersal of C. africana inoculum.

'Rubygem' strawberry

'Rubygem', a new short-day strawberry (Fragaria xananassa Duch.), produces high yields of moderately firm, attractive well-flavored fruit from late autumn through early spring in the strawberry-growing district in Southeast Queensland. 'Rubygem' is recommended for trial in areas with mild winter climates, especially where rainfall is unlikely and a well-flavored berry is required.

Identification and host-plant associations of Australian Sericothripinae (Thysanoptera, Thripidae)

The Sericothripinae is a largely tropical group of about 140 species that are often strikingly bicoloured and have complex surface sculpture, but for which the biology is poorly known. Although 15 genera have been described in this subfamily, only three of these are currently recognised, with five new generic synonymies indicated here. In Australia, Sericothrips Haliday is introduced, with one European species deployed as a weed biological control agent. Hydatothrips Karny comprises 43 species worldwide, with six species found in Australia, of which two are shared with Southeast Asia, and four are associated with the native vine genus, Parsonsia. Neohydatothrips John comprises 96 species worldwide, with nine species in Australia, of which one is shared with Southeast Asia and two are presumably introduced from the Americas. Illustrated keys are provided to the three genera and 16 species from Australia, including six new species [Hydatothrips aliceae; H. bhattii; H. williamsi; Neohydatothrips barrowi, N. bellissi, N. katherinae]. One new specific synonym is recognised [Hydatothrips haschemi Girault (= H. palawanensis Kudo)], also four new generic synonyms [Neohydatothrips John (= Faureana Bhatti; Onihothrips Bhatti; Sariathrips Bhatti; Papiliothrips Bhatti); Sericothrips Haliday (= Sussericothrips Han)].

The distribution of Fasciola hepatica in Queensland, Australia, and the potential impact of introduced snail intermediate hosts

A survey was conducted to establish the distribution of the liver fluke, Fasciola hepatica, in the state of Queensland, Australia, and to evaluate the impact of the introduced snail intermediate hosts, Pseudosuccinia columella and Austropeplea viridis. Serum samples from a total of 5103 homebred cattle in 142 beef herds distributed throughout the state and 523 pooled milk samples from dairy herds from the state's major dairying regions were tested for antibodies to F. hepatica by ELISA. Snails were collected on infected properties around the limits of the F. hepatica distribution. F. hepatica infection was detected in 44 dairy herds and two beef herds. The distribution of infected herds indicates that F. hepatica is established only in southeast Queensland. The distribution there was patchy but the parasite was more widespread than suggested by an earlier survey. The predominant intermediate host species found along the northern limit of the distribution was P. columella. We conclude that the introduction of P. columella and A. viridis has not yet had a major impact on the distribution of F. hepatica in Queensland. However, the presence of P. columella, which is much more adaptable to tropical habitats than the native intermediate host, Austropeplea tomentosa, at the northern limit of the F. hepatica distribution suggests that there is potential for the parasite to expand its range.

A marker-assisted backcross approach for developing submergence-tolerant rice cultivars

Submergence stress regularly affects 15 million hectares or more of rainfed lowland rice areas in South and Southeast Asia. A major QTL on chromosome 9, Sub1, has provided the opportunity to apply marker assisted backcrossing (MAB) to develop submergence tolerant versions of rice cultivars that are widely grown in the region. In the present study, molecular markers that were tightly linked with Sub1, flanking Sub1, and unlinked to Sub1 were used to apply foreground, recombinant, and background selection, respectively, in backcrosses between a submergence-tolerant donor and the widely grown recurrent parent Swarna. By the BC2F2 generation a submergence tolerant plant was identified that possessed Swarna type simple sequence repeat (SSR) alleles on all fragments analyzed except the tip segment of rice chromosome 9 that possessed the Sub1 locus. A BC3F2 double recombinant plant was identified that was homozygous for all Swarna type alleles except for an approximately 2.3-3.4 Mb region surrounding the Sub1 locus. The results showed that the mega variety Swarna could be efficiently converted to a submergence tolerant variety in three backcross generations, involving a time of two to three years. Polymorphic markers for foreground and recombinant selection were identified for four other mega varieties to develop a wider range of submergence tolerant varieties to meet the needs of farmers in the flood-prone regions. This approach demonstrates the effective use of marker assisted selection for a major QTL in a molecular breeding program.

Successful management of colletotrichum crown and stolon rot in runner production in sub-tropical Australia

Crown, stolon, and petiole rots caused by Colletotrichum gloeosporioides (C.g.) were first identified in runner beds of the Queensland Approved Runner Scheme (QARS) in February 1989. The outbreaks occurred annually from 1990 to 1994. Minor losses in subsequent fruit crops occurred from 1990 to 1993, with 50% post-establishment losses occurring on fruit farms in southeast Queensland in 1994. The objective of this work was to provide a control strategy for the disease that would give stability to the QARS. Runner-bed trials in 1993-1994 showed that Octave® (462 g/kg prochloraz as the MnCl2 complex) was highly effective in reducing the incidence field symptoms and laboratory recovery of C.g. from symptomless petioles. A simple detached petiole laboratory test for measuring fungicide efficacy in runner bed trials and for laboratory screening of fungicides, is described. Scheme protocols were changed to require that only foundation plants from tissue culture were allowed onto QARS sites. These were to be symptomless and to have tested negative for the presence of C.g. The application of Octave® at fortnightly intervals in all QARS nurseries has reduced the level of visible symptoms and the laboratory recovery of C.g. from symptomless petioles to almost zero.

The determination of essential oils in Sandalwood via NIR Spectroscopy

Sandalwood oil is widely used in the medicinal, cosmetic and aromatherapy industries. The oil is distilled from the heartwood of the sandalwood tree Santalum - a genus of hemi-parasitic tree species occurring throughout South and Southeast Asia, Australia and the Pacific. With international concern on the sustainability Sandalwood oil (Fox, 2000), the quality of oil entering the market is being compromised either through extraction from underdeveloped heartwoods or through adulteration with lower grade Sandalwood oils or synthetic substitutes (Howes et al. 2004). Although no standard method exists to assess the quality of Sandalwood oil, the International Organisation for Standardisation recommends GCMS analysis of santalol oil content. NIR spectroscopy has had a demonstrated success for other essential oils (Schulz et al. 2004, Steur et al. 2001). In addition, NIR spectroscopy has also been applied as both a qualitative and quantitative analytical tool in the forestry industry (Steur et al. 2001). This project aimed to assess the ability of NIR spectroscopy as a non-invasive, rapid and cheap analytical alternative to GCMS for Santalol determination.

Comparative productivity of irrigated short-term ryegrass (Lolium multiflorum) pasture receiving nitrogen, grown alone or in a mixture with white (Trifolium repens) and Persian (T. resupinatum) clovers

Dairy farms in subtropical Australia use irrigated, annually sown short-term ryegrass (Lolium multiflorum) or mixtures of short-term ryegrass and white (Trifolium repens) and Persian (shaftal) (T. resupinatum) clover during the winter-spring period in all-year-round milk production systems. A series of small plot cutting experiments was conducted in 3 dairying regions (tropical upland, north Queensland, and subtropical southeast Queensland and northern New South Wales) to determine the most effective rate and frequency of application of nitrogen (N) fertiliser. The experiments were not grazed, nor was harvested material returned to the plots, after sampling. Rates up to 100 kg N/ha.month (as urea or calcium ammonium nitrate) and up to 200 kg N/ha every 2 months (as urea) were applied to pure stands of ryegrass in 1991. In 1993 and 1994, urea, at rates up to 150 kg N/ha.month and to 200 kg N/ha every 2 months, was applied to pure stands of ryegrass; urea, at rates up to 50 kg N/ha.month, was also applied to ryegrass-clover mixtures. The results indicate that applications of 50-85 kg N/ha.month can be recommended for short-term ryegrass pastures throughout the subtropics and tropical uplands of eastern Australia, irrespective of soil type. At this rate, dry matter yields will reach about 90% of their potential, forage nitrogen concentration will be increased, there is minimal risk to stock from nitrate poisoning and there will be no substantial increase in soil N. The rate of N for ryegrass-clover pastures is slightly higher than for pure ryegrass but, at these rates, the clover component will be suppressed. However, increased ryegrass yields and higher forage nitrogen concentrations will compensate for the reduced clover component. At application rates up to 100 kg N/ha.month, build-up of NO3--N and NH4+-N in soil was generally restricted to the surface layers (0-20 cm) of the soil, but there was a substantial increase throughout the soil profile at 150 kg N/ha.month. The build-up of NO3--N and NH4+-N was greater and was found at lower rates on the lighter soil compared with heavy clays. Generally, most of the soil N was in the NO3--N form and most was in the top 20 cm.

Analysis and Modelling of the Effects of Water Stress on Maize Growth and Yield in Dryland Conditions.

It is essential to provide experimental evidence and reliable predictions of the effects of water stress on crop production in the drier, less predictable environments. A field experiment undertaken in southeast Queensland, Australia with three water regimes (fully irrigated, rainfed and irrigated until late canopy expansion followed by rainfed) was used to compare effects of water stress on crop production in two maize (Zea mays L.) cultivars (Pioneer 34N43 and Pioneer 31H50). Water stress affected growth and yield more in Pioneer 34N43 than in Pioneer 31H50. A crop model APSIM-Maize, after having been calibrated for the two cultivars, was used to simulate maize growth and development under water stress. The predictions on leaf area index (LAI) dynamics, biomass growth and grain yield under rain fed and irrigated followed by rain fed treatments was reasonable, indicating that stress indices used by APSIM-Maize produced appropriate adjustments to crop growth and development in response to water stress. This study shows that Pioneer 31H50 is less sensitive to water stress and thus a preferred cultivar in dryland conditions, and that it is feasible to provide sound predictions and risk assessment for crop production in drier, more variable conditions using the APSIM-Maize model.

Zoysia matrella, Manila Grass 'A-1'

‘A-1’ was selected from a breeding population of 40 seedling Zoysia matrella plants from various parts of Southeast Asia (Japan, Philippines, China, Korea, Vietnam and Thailand). The original plants were vegetatively propagated and evaluated first in pots. A shortlist of selected genotypes was expanded to field plantings at Sheldon, QLD and evaluated against existing Z. matrella and Z. matrella x Z. japonica hybrid cultivars under mowing heights from 10 to 25mm and under shade levels ranging from 0 to 80%. ‘A-1’ showed higher tiller density and a more prostrate growth habit than the parent ecotype, and was selected from the subsequent breeding population on the basis of its superior turf colour and quality under mowing for 6 years and its shade tolerance as shown by its ability to maintain density of the mown sward under greatly reduced light levels (70-80% shade). Additional observations regarding climatic adaptation were made in Cairns, QLD, and Melbourne, VIC, respectively. Breeder: Donald S Loch, Alexandra Hills, QLD. PBR Certificate Number 3649, Application Number 2008/091, granted 16 December 2008.