The host range and biology of Cometaster pyrula; a biocontrol agent for Acacia nilotica subsp. indica in Australia

Prickly acacia, Acacia nilotica subsp. indica (Benth.) Brenan, a major weed of the Mitchell Grass Downs of northern Queensland, Australia, has been the target of biological control projects since the 1980s. The leaf-feeding caterpillar Cometaster pyrula (Hopffer) was collected from Acacia nilotica subsp. kraussiana (Benth.) Brenan during surveys in South Africa to find suitable biological control agents, recognised as a potential agent, and shipped into a quarantine facility in Australia. Cometaster pyrula has a life cycle of approximately 2 months during which time the larvae feed voraciously and reach 6 cm in length. Female moths oviposit a mean of 339 eggs. When presented with cut foliage of 77 plant species, unfed neonates survived for 7 days on only Acacia nilotica subsp. indica and Acacia nilotica subsp. kraussiana. When unfed neonates were placed on potted plants of 14 plant species, all larvae except those on Acacia nilotica subsp. indica and Acacia nilotica subsp. kraussiana died within 10 days of placement. Cometaster pyrula was considered to be highly host specific and safe to release in Australia. Permission to release C. pyrula in Australia was obtained and the insect was first released in north Queensland in October 2004. The ecoclimatic model CLIMEX indicated that coastal Queensland was climatically suitable for this insect but that inland areas were only marginally suitable.

Action learning in partnership with Landcare and catchment management groups to support increased pasture sowings in southern inland Queensland

The incorporation of sown pastures as short-term rotations into the cropping systems of northern Australia has been slow. The inherent chemical fertility and physical stability of the predominant vertisol soils across the region enabled farmers to grow crops for decades without nitrogen fertiliser, and precluded the evolution of a crop–pasture rotation culture. However, as less fertile and less physically stable soils were cropped for extended periods, farmers began to use contemporary farming and sown pasture technologies to rebuild and maintain their soils. This has typically involved sowing long-term grass and grass–legume pastures on the more marginal cropping soils of the region. In partnership with the catchment management authority, the Queensland Murray–Darling Committee (QMDC) and Landcare, a pasture extension process using the LeyGrain™ package was implemented in 2006 within two Grain & Graze projects in the Maranoa-Balonne and Border Rivers catchments in southern inland Queensland. The specific objectives were to increase the area sown to high quality pasture and to gain production and environmental benefits (particularly groundcover) through improving the skills of producers in pasture species selection, their understanding and management of risk during pasture establishment, and in managing pastures and the feed base better. The catalyst for increasing pasture sowings was a QMDC subsidy scheme for increasing groundcover on old cropping land. In recognising a need to enhance pasture knowledge and skills to implement this scheme, the QMDC and Landcare producer groups sought the involvement of, and set specific targets for, the LeyGrain workshop process. This is a highly interactive action learning process that built on the existing knowledge and skills of the producers. Thirty-four workshops were held with more than 200 producers in 26 existing groups and with private agronomists. An evaluation process assessed the impact of the workshops on the learning and skill development by participants, their commitment to practice change, and their future intent to sow pastures. The results across both project catchments were highly correlated. There was strong agreement by producers (>90%) that the workshops had improved knowledge and skills regarding the adaptation of pasture species to soils and climates, enabling a better selection at the paddock level. Additional strong impacts were in changing the attitudes of producers to all aspects of pasture establishment, and the relative species composition of mixtures. Producers made a strong commitment to practice change, particularly in managing pasture as a specialist crop at establishment to minimise risk, and in the better selection and management of improved pasture species (particularly legumes and the use of fertiliser). Producers have made a commitment to increase pasture sowings by 80% in the next 5 years, with fourteen producers in one group alone having committed to sow an additional 4893 ha of pasture in 2007–08 under the QMDC subsidy scheme. The success of the project was attributed to the partnership between QMDC and Landcare groups who set individual workshop targets with LeyGrain presenters, the interactive engagement processes within the workshops themselves, and the follow-up provided by the LeyGrain team for on-farm activities.

Is Malting Barley Better Feed for Cattle than Feed Barley?

Barley grain from a combined intermediate and advanced barley breeding trial was assessed for grain, feed and malt quality from two sites over two consecutive years, with the objective to ascertain relationships between these traits. Results indicated there were genetic effects for both malt (hot water extract and friability) and “feed” traits (as measured by hardness, acid detergent fibre, starch and in-sacco dry matter digestibility). The feed trait values were generally independent of the malt trait values. However, there were positive relationships between friability, hardness and protein, as well as a negative relationship between extract and husk. Extract also had a positive relationship with test weight but appeared to be independent from the feed traits. Test weight also showed little relationship to the feed traits. Heritability values ranged from low to high for almost all traits. This study details where both malt and cattle feed parameters have been compared and the results indicated that while malt and feed traits do not correlate directly, malt cultivars can exhibit excellent feed characteristics, equal to or better than feed cultivars. This data highlights the benefit of selecting for malt quality even if a breeding program would be interested at targeting specific feed quality.

Validating economic and environmental sustainability of a short-term summer forage legume in dryland wheat cropping systems in south-west Queensland.

The present study set out to test the hypothesis through field and simulation studies that the incorporation of short-term summer legumes, particularly annual legume lablab (Lablab purpureus cv. Highworth), in a fallow-wheat cropping system will improve the overall economic and environmental benefits in south-west Queensland. Replicated, large plot experiments were established at five commercial properties by using their machineries, and two smaller plot experiments were established at two intensively researched sites (Roma and St George). A detailed study on various other biennial and perennial summer forage legumes in rotation with wheat and influenced by phosphorus (P) supply (10 and 40 kg P/ha) was also carried out at the two research sites. The other legumes were lucerne (Medicago sativa), butterfly pea (Clitoria ternatea) and burgundy bean (Macroptilium bracteatum). After legumes, spring wheat (Triticum aestivum) was sown into the legume stubble. The annual lablab produced the highest forage yield, whereas germination, establishment and production of other biennial and perennial legumes were poor, particularly in the red soil at St George. At the commercial sites, only lablab-wheat rotations were experimented, with an increased supply of P in subsurface soil (20 kg P/ha). The lablab grown at the commercial sites yielded between 3 and 6 t/ha forage yield over 2-3 month periods, whereas the following wheat crop with no applied fertiliser yielded between 0.5 to 2.5 t/ha. The wheat following lablab yielded 30% less, on average, than the wheat in a fallow plot, and the profitability of wheat following lablab was slightly higher than that of the wheat following fallow because of greater costs associated with fallow management. The profitability of the lablab-wheat phase was determined after accounting for the input costs and additional costs associated with the management of fallow and in-crop herbicide applications for a fallow-wheat system. The economic and environmental benefits of forage lablab and wheat cropping were also assessed through simulations over a long-term climatic pattern by using economic (PreCAPS) and biophysical (Agricultural Production Systems Simulation, APSIM) decision support models. Analysis of the long-term rainfall pattern (70% in summer and 30% in winter) and simulation studies indicated that ~50% time a wheat crop would not be planted or would fail to produce a profitable crop (grain yield less than 1 t/ha) because of less and unreliable rainfall in winter. Whereas forage lablab in summer would produce a profitable crop, with a forage yield of more than 3 t/ha, ~90% times. Only 14 wheat crops (of 26 growing seasons, i.e. 54%) were profitable, compared with 22 forage lablab (of 25 seasons, i.e. 90%). An opportunistic double-cropping of lablab in summer and wheat in winter is also viable and profitable in 50% of the years. Simulation studies also indicated that an opportunistic lablab-wheat cropping can reduce the potential runoff+drainage by more than 40% in the Roma region, leading to improved economic and environmental benefits.

Poor adoption of ley-pastures in south-west Queensland: biophysical, economic and social constraints.

The present review identifies various constraints relating to poor adoption of ley-pastures in south-west Queensland, and suggests changes in research, development and extension efforts for improved adoption. The constraints include biophysical, economic and social constraints. In terms of biophysical constraints, first, shallower soil profiles with subsoil constraints (salt and sodicity), unpredictable rainfall, drier conditions with higher soil temperature and evaporative demand in summer, and frost and subzero temperature in winter, frequently result in a failure of established, or establishing, pastures. Second, there are limited options for legumes in a ley-pasture, with the legumes currently being mostly winter-active legumes such as lucerne and medics. Winter-active legumes are ineffective in improving soil conditions in a region with summer-dominant rainfall. Third, most grain growers are reluctant to include grasses in their ley-pasture mix, which can be uneconomical for various reasons, including nitrogen immobilisation, carryover of cereal diseases and depressed yields of the following cereal crops. Fourth, a severe depletion of soil water following perennial ley-pastures (grass + legumes or lucerne) can reduce the yields of subsequent crops for several seasons, and the practice of longer fallows to increase soil water storage may be uneconomical and damaging to the environment. Economic assessments of integrating medium- to long-term ley-pastures into cropping regions are generally less attractive because of reduced capital flow, increased capital investment, economic loss associated with establishment and termination phases of ley-pastures, and lost opportunities for cropping in a favourable season. Income from livestock on ley-pastures and soil productivity gains to subsequent crops in rotation may not be comparable to cropping when grain prices are high. However, the economic benefits of ley-pastures may be underestimated, because of unaccounted environmental benefits such as enhanced water use, and reduced soil erosion from summer-dominant rainfall, and therefore, this requires further investigation. In terms of social constraints, the risk of poor and unreliable establishment and persistence, uncertainties in economic and environmental benefits, the complicated process of changing from crop to ley-pastures and vice versa, and the additional labour and management requirements of livestock, present growers socially unattractive and complex decision-making processes for considering adoption of an existing medium- to long-term ley-pasture technology. It is essential that research, development and extension efforts should consider that new ley-pasture options, such as incorporation of a short-term summer forage legume, need to be less risky in establishment, productive in a region with prevailing biophysical constraints, economically viable, less complex and highly flexible in the change-over processes, and socially attractive to growers for adoption in south-west Queensland.

The performance of irrigated mixtures of tall fescue, ryegrass and white clover in subtropical Australia. 2. The effects on yield and botanical composition of managing for quality.

The effects on yield, botanical composition and persistence, of using a variable defoliation schedule as a means of optimising the quality of the tall fescue component of simple and complex temperate pasture mixtures in a subtropical environment was studied in a small plot cutting experiment at Gatton Research Station in south-east Queensland. A management schedule of 2-, 3- and 4-weekly defoliations in summer, autumn and spring and winter, respectively, was imposed on 5 temperate pasture mixtures: 2 simple mixtures including tall fescue (Festuca arundinacea) and white clover (Trifolium repens); 2 mixtures including perennial ryegrass (Lolium perenne), tall fescue and white clover; and a complex mixture, which included perennial ryegrass, tall fescue, white, red (T. pratense) and Persian (T. resupinatum) clovers and chicory (Cichorium intybus). Yield from the variable cutting schedule was 9% less than with a standard 4-weekly defoliation. This loss resulted from reductions in both the clover component (13%) and cumulative grass yield (6%). There was no interaction between cutting schedule and sowing mixture, with simple and complex sowing mixtures reacting in a similar manner to both cutting schedules. The experiment also demonstrated that, in complex mixtures, the cutting schedules used failed to give balanced production from all sown components. This was especially true of the grass and white clover components of the complex mixture, as chicory and Persian clover components dominated the mixtures, particularly in the first year. Quality measurements (made only in the final summer) suggested that variable management had achieved a quality improvement with increases in yields of digestible crude protein (19%) and digestible dry matter (9%) of the total forage produced in early summer. The improvements in the yields of digestible crude protein and digestible dry matter of the tall fescue component in late summer were even greater (28 and 19%, respectively). While advantages at other times of the year were expected to be smaller, the data suggested that the small loss in total yield was likely to be offset by increases in digestibility of available forage for grazing stock, especially in the critical summer period.

The performance of irrigated mixtures of tall fescue, ryegrass and white clover in subtropical Australia. 1. The effects of sowing mixture combinations, nitrogen and oversowing on establishment, productivity, botanical composition and persistence.

In the subtropics of Australia, the ryegrass component of irrigated perennial ryegrass (Lolium perenne) - white clover (Trifolium repens) pastures declines by approximately 40% in the summer following establishment, being replaced by summer-active C4 grasses. Tall fescue (Festuca arundinacea) is more persistent than perennial ryegrass and might resist this invasion, although tall fescue does not compete vigorously as a seedling. This series of experiments investigated the influence of ryegrass and tall fescue genotype, sowing time and sowing mixture as a means of improving tall fescue establishment and the productivity and persistence of tall fescue, ryegrass and white clover-based mixtures in a subtropical environment. Tall fescue frequency at the end of the establishment year decreased as the number of companion species sown in the mixture increased. Neither sowing mixture combinations nor sowing rates influenced overall pasture yield (of around 14 t/ha) in the establishment year but had a significant effect on botanical composition and component yields. Perennial ryegrass was less competitive than short-rotation ryegrass, increasing first-year yields of tall fescue by 40% in one experiment and by 10% in another but total yield was unaffected. The higher establishment-year yield (3.5 t/ha) allowed Dovey tall fescue to compete more successfully with the remaining pasture components than Vulcan (1.4 t/ha). Sowing 2 ryegrass cultivars in the mixture reduced tall fescue yields by 30% compared with a single ryegrass (1.6 t/ha), although tall fescue alone achieved higher yields (7.1 t/ha). Component sowing rate had little influence on composition or yield. Oversowing the ryegrass component into a 6-week-old sward of tall fescue and white clover improved tall fescue, white clover and overall yields in the establishment year by 83, 17 and 11%, respectively, but reduced ryegrass yields by 40%. The inclusion of red (T. pratense) and Persian (T. resupinatum) clovers and chicory (Cichorium intybus) increased first-year yields by 25% but suppressed perennial grass and clover components. Yields were generally maintained at around 12 t/ha/yr in the second and third years, with tall fescue becoming dominant in all 3 experiments. The lower tall fescue seeding rate used in the first experiment resulted in tall fescue dominance in the second year following establishment, whereas in Experiments 2 and 3 dominance occurred by the end of the first year. Invasion by the C4 grasses was relatively minor (<10%) even in the third year. As ryegrass plants died, tall fescue and, to a lesser extent, white clover increased as a proportion of the total sward. Treatment effects continued into the second, but rarely the third, year and mostly affected the yield of one of the components rather than total cumulative yield. Once tall fescue became dominant, it was difficult to re-introduce other pasture components, even following removal of foliage and moderate renovation. Severe renovation (reducing the tall fescue population by at least 30%) seems a possible option for redressing this situation.

Factors affecting localized abundance and distribution of lesser mealworm in earth-floor broiler houses in subtropical Australia.

Factors that influence the localized abundance and distribution of lesser mealworm, Alphitobius diaperinus (Panzer), in litter of two compacted earth-floor broiler houses in subtropical Australia were studied using various experimental manipulations. Numbers of lesser mealworms substantially increased inside caged areas and under uncaged empty feed pans placed in open areas of the houses. These populations were found to be localized and independent of chicken-feed, manure, and high beetle populations that normally occur under existing feed pans. Substantial horizontal movement of larvae to under feed pans was recorded. Placing metal barriers around these pans significantly restricted this movement. In almost all treatments, lesser mealworms typically peaked in numbers during the middle of the flock time. This temporal pattern of abundance also was observed under pans within barriers, where relatively low insect numbers occurred, but it was not observed in uncaged open areas (where chickens had complete access). It is likely that larvae do not establish in open areas, but fluctuate in numbers as they either move to refuges away from chickens or suffer high rates of mortality. In these refuges, larvae peak in numbers and then leave the litter environment to pupate in the earth floor before the end of the flock time. This behavior might be exploited for management of lesser mealworm by targeting applications of control agents.

Mineralogical and metallurgical examination of fluorosilicate mineral floatation in the Ok Tedi circuit

The Ok Tedi copper orebody consists of porphyry and skarn orebodies. The skarn orebodies, identified by different mineralogy, are the source of high intermittent fluorine levels in the mill concentrates. This paper discusses the results of the work undertaken to characterize the various fluorine-bearing minerals in samples of final copper concentrates and the distribution of fluorine amongst the minerals. Quantification of each mineral in mill feed and various flotation streams at Ok Tedi enables an understanding of the quantitative response of fluorine-bearing minerals to flotation. The metallurgical behavior of fluorine in the flotation process is also discussed.

The use of temperate species in the Australian subtropics.

Temperate species and tropical crop silage are the basis for forage production for the dairy industry in the Australian subtropics. Irrigation is the key resource needed for production, with little survival of temperate species under rain-grown conditions except for lucerne. Annual ryegrass (Lolium multiflorum), fertilised with either inorganic nitrogen or grown with clovers, is the main cool season forage for the dairy industry. It is sown into fully prepared seedbeds, oversown into tropical grasses, especially kikuyu (Pennisetum clandestinum) or sown after mulching. There has been a continual improvement in the performance of annual and hybrid ryegrass cultivars over the last 25 years. In small plot, cutting experiments, yields of annual ryegrass typically range from 15 to 21 t DM/ha, with equivalent on-farm yields of 7 to 14 t DM/ha of utilised material. Rust (Puccinia coronata) remains the major concern although resistance is more stable than in oats. There have also been major improvements in the performance of perennial ryegrass (L. perenne) cultivars although their persistence under grazing is insufficient to make them a reliable forage source for the subtropics. On the other hand, tall fescue (Festuca arundinacea) and prairie grass (Bromus willdenowii) cultivars perform well under cutting and grazing, although farmer resistance to the use of tall fescue is strong. White clover (Trifolium repens) is a reliable and persistent performer although disease usually reduces its performance in the third year after sowing. Persian (Shaftal) annual clover (T. resupinatum) gives good winter production but the performance of berseem clover (T. alexandrinum) is less reliable and the sub clovers (T. subterraneum) are generally not suited to clay soils of neutral to alkaline pH. Lucerne (Medicago sativa), either as a pure stand or in mixtures, is a high producing legume under both irrigation and natural rainfall. Understanding the importance of leaf and crown diseases, and the development of resistant cultivars, have been the reasons for its reliability. Insects on temperate species are not as serious a problem in the subtropics as in New Zealand (NZ). Fungal and viral diseases, on the other hand, cause many problems and forage performance would benefit from more research into resistance.

Effect of sorghum ergot (Claviceps africana) on the performance of steers (Bos taurus) in a feedlot.

The effect of ergot (Claviceps africana) in naturally infected sorghum was assessed in feedlot rations. Thirty-two Hereford steers (Bos taurus) in individual pens with access to shade were adapted to feedlot conditions and then offered one of four rations containing 0, 4.4, 8.8 or 17.6 mg/kg of ergot alkaloids (84% dihydroergosine, 10% dihydroelymoclavine and 6% festuclavine), equivalent to ~0, 10, 20 or 40 g/kg ergot (sclerotia/sphacelia) in the rations. These rations were withdrawn at noon on the second day because of severe hyperthermia and almost complete feed refusal in ergot-fed steers. After recovery on ergot-free rations for 5 days, treatment groups were incrementally introduced, over a further 3–12 days, to rations containing 0, 1.1, 2.2 or 4.4 mg/kg of alkaloids (~0, 2.5, 5 or 10 g/kg ergot, respectively). Relative exposure to ergot was maintained, so that the zero- (control), low-, medium- and high-ergot groups remained so. Steers were individually fed ad libitum, and water was freely available. Steers in all ergot-fed groups had significantly elevated rectal temperatures at 0800–1000 hours, even when the temperature–humidity index was only moderate (~70), and displayed other signs of hyperthermia (increased respiration rate, mouth breathing, excessive salivation and urination), as the temperature–humidity index increased to 73–79 during the day. Plasma prolactin was significantly reduced in ergot-fed groups. Voluntary feed intakes (liveweight basis) of the ergot-fed groups were significantly reduced, averaging 94, 86 and 86%, respectively, of the feed intakes of the control group. Hair coats were rough. While the control steers grew from a mean initial liveweight of 275 kg to a suitable slaughter weight of 455 kg in 17 weeks (growth rate 1.45 kg/day), ergot-fed groups gained only 0.77–1.10 kg/day and took at least 5 weeks longer to reach the slaughter weight, despite removal of ergot at the same time as control steers were sent to slaughter. Sorghum ergot, even at low concentrations (1.1 mg alkaloids/kg feed) is severely detrimental to the performance of steers in the feedlot.

Coordinator's report: rules for nomenclature and gene symbolization in barley.

In this volume, the recommended rules for nomenclature and gene symbolization in barley are reprinted. The current lists of new and revised barley genetic stock descriptions are presented by BGS number order and by locus symbol in alphabetical order.

Utilisation of local ingredients in commercial pig feeds

The long-term competitiveness of the both the Vietnamese feed and pig production industries are constrained and under pressure whilst the industry is dependent on the use of imported feed ingredients in diets for animal production. These cost pressures are a result of import taxes, transport costs, currency fluctuations and feed supply limitations. By undertaking studies on available resources which are currently under-utilised and with potential as local feeds, we can prove their suitability for use as feedstuffs in pig diets and as replacements for imported feed ingredients. In undertaking this process we can lower feeding costs for pig production in Vietnam by the use of local feeds which are cheaper, generate new industries in Vietnam harvesting or processing these feeds and increase the incomes of Vietnamese workers who are involved in producing these by-products. Our project has shown that rubber seed, when processed correctly to lower the hydrogen cyanide content, is a safe and suitable protein meal feedstuff for use in pig diets with the potential to replace significant quantities of imported soybean and fishmeal in Vietnamese pig diets as long as diets are balanced for any amino acid shortfalls. Our peanut studies have shown that use of binders can help alleviate pig production problems with aflatoxin content in peanut meals. Further work is needed to characterise the fate of the bound aflatoxin to see if there is any meat residue risk. Cassava residue is a resultant by-product from starch extraction in both large and small cassava processing factories. Sub-samples from these two mill types were collected and evaluated for residue HCN. Analyses has shown that the processing and sun drying results in a product with relatively consistent low HCN content. Chemical analyses also reveal that significant residual starch also remains in this by-product. Digestibility studies and pig performance feeding studies have shown that cassava residue can be included in diets at 30% with no adverse effect, although the higher fibre content of this product means that strategically, cassava residue is more suitably used in finisher and sow diets. Research has examined the digestible energy content of a number of sunflower meal types available in Australia and identified major differences in their energy value based on processing, additionally, amino acid analysis has shown a significantly lower lysine content than previous reported. We also examined the digestible energy content of a number of Australian stylo forage legume harvest batches and identified the differences in their energy value based on age/harvest time of the forage legume. Analysis results of various stylo cuts showed that the early cut stylo has a higher starch content and lower fibre fraction content than observed in late and recut stylo which were allowed to grow longer. As a result the faecal digestible energy content was higher for the early cut stylo than for the subsequent cut stylo material which had been allowed to become woody. The results have shown that feeding of stylo meal does provide some nutritive value to the pig with increased energy and nitrogen supply, with a portion of the nitrogen presented which the pig is able to retain. Based on nutrient and fibre content stylo could have a useful role in sow feeding and satiety under non-stall housing situations. With increasing Vietnamese investment in rubber production seen with larger areas under plantations the amounts of rubber seed available for animal feeding will grow significantly over the next 15 years and the importance of the by-product ie rubber seed meal as a protein source in diets for Vietnamese pigs.

Screening of new lines of cereal grains for inclusion in Near Infra Red Scan calibrations

The project will provide enough data for a reliable and robust NIRs. It will more fully develop the in vitro method to enable less costly assessment of grains in the future. It will also provide a reliable assessment for DE which is the most expensive component of pig feed.