Helicoverpa armigera (Hubner): can wheat stubble protect cotton plants against attack?

When investigating strategies for Helicoverpa armigera (Hubner) control, it is important to understand oviposition behaviour. Cotton (Gossypium hirsutum) was sown into standing wheat (Triticum astivum L.) stubble in a closed arena to investigate the effect of stubble on H. armigera moth behaviour and oviposition. Infrared cameras were used to track moths and determine whether stubble acted as a physical barrier or provided camouflage to cotton plants, thereby reducing oviposition. Searching activity was observed to peak shortly before dawn (03:00 and 04:00 h) and remained high until just after dawn (4 h window). Moths spent more time resting on cotton plants than spiralling above them, and the least time flying across the arena. While female moths spent more time searching for cotton plants growing in wheat stubble, the difference in oviposition was not significant. As similar numbers of eggs were laid on cotton plants with stubble (3.5/plant SE +/- 0.87) and without stubble (2.5/plant SE +/- 0.91), wheat stubble does not appear to provide camouflage to cotton plants. There was no significant difference in the location of eggs deposited on cotton plants with and without stubble, although more eggs were laid on the tops of cotton leaves in wheat stubble. As the spatial and temporal distribution of eggs laid on the cotton plant is a crucial component of population stability, eggs laid on the upper side of leaves on cotton plants may be more prone to fatalities caused by environmental factors such as wind and rain. Therefore, although stubble did not influence the number of eggs laid, it did affect their distribution on the plant, which may result in increased mortality of eggs on cotton plants sown into standing wheat stubble.

Do parasitic flies attack mites? Evidence in Baltic amber

We provide the first evidence of a small-headed fly planidium (first instar larva; Diptera: Acroceridae) associated with a whirligig mite (Acari: Acariformes: Prostigmata: Anystina: Anystidae) in Baltic amber. This fossil is surprising as parasitic nematodes are the only metazoans known to successfully attack acariform mites, and Acroceridae are believed to be host-restricted parasitoids of spiders. The fossil corroborates a previously published, but widely dismissed, paper that first reported parasitism of parasitengone mites by acrocerid planidia. The possible natural history implications of this find are discussed.

Detection and use of QTL for complex traits in multiple environments.

QTL mapping methods for complex traits are challenged by new developments in marker technology, phenotyping platforms, and breeding methods. In meeting these challenges, QTL mapping approaches will need to also acknowledge the central roles of QTL by environment interactions (QEI) and QTL by trait interactions in the expression of complex traits like yield. This paper presents an overview of mixed model QTL methodology that is suitable for many types of populations and that allows predictive modeling of QEI, both for environmental and developmental gradients. Attention is also given to multi-trait QTL models which are essential to interpret the genetic basis of trait correlations. Biophysical (crop growth) model simulations are proposed as a complement to statistical QTL mapping for the interpretation of the nature of QEI and to investigate better methods for the dissection of complex traits into component traits and their genetic controls.

Membrane fractionation technologies for high quality mill sugar and value-added by products - an integrated sugar production process concept model.

Membrane filtration technology has been proven to be a technically sound process to improve the quality of clarified cane juice and subsequently to increase the productivity of crystallisation and the quality of sugar production. However, commercial applications have been hindered because the benefits to crystallisation and sugar quality have not outweighed the increased processing costs associated with membrane applications. An 'Integrated Sugar Production Process (ISPP) Concept Model' is proposed to recover more value from the non-sucrose streams generated by membrane processing. Pilot scale membrane fractionation trials confirmed the technical feasibility of separating high-molecular weight, antioxidant and reducing sugar fractions from cane juice in forms suitable for value recovery. It was also found that up to 40% of potassium salts from the juice can be removed by membrane application while removing the similar amount of water with potential energy saving in subsequent evaporation. Application of ISPP would allow sugar industry to co-produce multiple products and high quality mill sugar while eliminating energy intensive refining processes.

Stem cankers on sunflower (Helianthus annuus) in Australia reveal a complex of pathogenic Diaporthe (Phomopsis) species.

The identification of Diaporthe (anamorph Phomopsis) species associated with stem canker of sunflower (Helianthus annuus) in Australia was studied using morphology, DNA sequence analysis and pathology. Phylogenetic analysis revealed three clades that did not correspond with known taxa, and these are believed to represent novel species. Diaporthe gulyae sp. nov. is described for isolates that caused a severe stem canker, specifically pale brown to dark brown, irregularly shaped lesions centred at the stem nodes with pith deterioration and mid-stem lodging. This pathogenicity of D. gulyae was confirmed by satisfying Koch's Postulates. These symptoms are almost identical to those of sunflower stem canker caused by D. helianthi that can cause yield reductions of up to 40% in Europe and the USA, although it has not been found in Australia. We show that there has been broad misapplication of the name D. helianthi to many isolates of Diaporthe ( Phomopsis) found causing, or associated with, stem cankers on sunflower. In GenBank, a number of isolates had been identified as D. helianthi, which were accommodated in several clades by molecular phylogenetic analysis. Two less damaging species, D. kochmanii sp. nov. and D. kongii sp. nov., are also described from cankers on sunflower in Australia.

The Colletotrichum boninense species complex

Although only recently described, Colletotrichum boninense is well established in literature as an anthracnose pathogen or endophyte of a diverse range of host plants worldwide. It is especially prominent on members of Amaryllidaceae, Orchidaceae, Proteaceae and Solanaceae. Reports from literature and preliminary studies using ITS sequence data indicated that C. boninense represents a species complex. A multilocus molecular phylogenetic analysis (ITS, ACT, TUB2, CHS-1, GAPDH, HIS3, CAL) of 86 strains previously identified as C. boninense and other related strains revealed 18 clades. These clades are recognised here as separate species, including C. boninense s. str., C. hippeastri, C. karstii and 12 previously undescribed species, C. annellatum, C. beeveri, C. brassicicola, C. brasiliense, C. colombiense, C. constrictum, C. cymbidiicola, C. dacrycarpi, C. novae-zelandiae, C. oncidii, C. parsonsiae and C. torulosum. Seven of the new species are only known from New Zealand, perhaps reflecting a sampling bias. The new combination C. phyllanthi was made, and C. dracaenae Petch was epitypified and the name replaced with C. petchii. Typical for species of the C. boninense species complex are the conidiogenous cells with rather prominent periclinal thickening that also sometimes extend to form a new conidiogenous locus or annellations as well as conidia that have a prominent basal scar. Many species in the C. boninense complex form teleomorphs in culture. TAXONOMIC NOVELTIES: New combination - Colletotrichum phyllanthi (H. Surendranath Pai) Damm, P.F. Cannon & Crous. Name replacement - C. petchii Damm, P.F. Cannon & Crous. New species - C. annellatum Damm, P.F. Cannon & Crous, C. beeveri Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. brassicicola Damm, P.F. Cannon & Crous, C. brasiliense Damm, P.F. Cannon, Crous & Massola, C. colombiense Damm, P.F. Cannon, Crous, C. constrictum Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. cymbidiicola Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. dacrycarpi Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. novae-zelandiae Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. oncidii Damm, P.F. Cannon & Crous, C. parsonsiae Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. torulosum Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir. Typifications: Epitypifications - C. dracaenae Petch.

A phylogenetic and taxonomic re-evaluation of the Bipolaris - Cochliobolus - Curvularia Complex

Three genera, Cochliobolus, Bipolaris and Curvularia form a complex that contains many plant pathogens, mostly on grasses (Poaceae) with a worldwide distribution. The taxonomy of this complex is confusing as frequent nomenclatural changes and refinements have occurred. There is no clear morphological boundary between the asexual genera Bipolaris and Curvularia, and some species show intermediate morphology. We investigated this complex based on a set of ex-type cultures and collections from northern Thailand. Combined gene analysis of rDNA ITS (internal transcribed spacer), GPDH (glyceraldehyde 3-phosphate dehydrogenase), LSU (large subunit) and EF1-α (translation elongation factor 1-α) shows that this generic complex divides into two groups. Bipolaris and Cochliobolus species clustered in Group 1 along with their type species, whereas Curvularia species (including species named as Bipolaris, Cochliobolus and Curvularia) clustered in Group 2, with its generic type. The nomenclatural conflict in this complex is resolved giving priority to the more commonly used established generic names Bipolaris and Curvularia. Modern descriptions of the genera Bipolaris and Curvularia are provided and species resolved in this study are transferred to one of these genera based on their phylogeny. © 2012 Mushroom Research Foundation.

Soral synapomorphies are significant for the systematics of the Ustilago-Sporisorium-Macalpinomyces complex (Ustilaginaceae)

The genera Ustilago, Sporisorium and Macalpinomyces are a polyphyletic complex of plant pathogenic fungi. The four main morphological characters used to define these genera have been considered homoplasious and not useful for resolving the complex. This study re-evaluates character homology and discusses the use of these characters for defining monophyletic groups recovered from a reconstructed phylogeny using four nuclear loci. Generic delimitation of smut fungi based on their hosts is also discussed as a means for identifying genera within this group. Morphological characters and host specificity can be used to circumscribe genera within the Ustilago-Sporisorium-Macalpinomyces complex.

A review of the Ustilago-Sporisorium-Macalpinomyces complex

The fungal genera Ustilago, Sporisorium and Macalpinomyces represent an unresolved complex. Taxa within the complex often possess characters that occur in more than one genus, creating uncertainty for species placement. Previous studies have indicated that the genera cannot be separated based on morphology alone. Here we chronologically review the history of the Ustilago-Sporisorium-Macalpinomyces complex, argue for its resolution and suggest methods to accomplish a stable taxonomy. A combined molecular and morphological approach is required to identify synapomorphic characters that underpin a new classification. Ustilago, Sporisorium and Macalpinomyces require explicit re-description and new genera, based on monophyletic groups, are needed to accommodate taxa that no longer fit the emended descriptions. A resolved classification will end the taxonomic confusion that surrounds generic placement of these smut fungi.

Is Mycoplasma bovis a missing component of the bovine respiratory disease complex in Australia?

Background: Bovine respiratory disease complex (BRDC) is a multi-factorial disease in which numerous factors, such as animal management, pathogen exposure and environmental conditions, contribute to the development of acute respiratory illness in feedlot cattle. The role of specific pathogens in the development of BRDC has been difficult to define because of the complex nature of the disease and the presence of implicated bacterial pathogens in the upper respiratory tract of healthy animals. Mycoplasma bovis is an important pathogen of cattle and recognised as a major contributor to cases of mastitis, caseonecrotic bronchopneumonia, arthritis and otitis media. To date, the role of M.bovis in the development of BRDC of Australian feeder cattle has not been investigated. Methods: In this review, the current literature pertaining to the role of M.bovis in BRDC is evaluated. In addition, preliminary data are presented that identify M.bovis as a potential contributor to BRDC in Australian feedlots, which has not been considered previously. Results and Conclusion: The preliminary results demonstrate detection of M.bovis in samples from all feedlots studied. When considered in the context of the reviewed literature, they support the inclusion of M.bovis on the list of pathogens to be considered during investigations into BRDC in Australia. © 2014 Australian Veterinary Association.

Host Tree Influences on Longicorn Beetle (Coleoptera: Cerambycidae) Attack in Subtropical Corymbia (Myrtales: Myrtaceae)

Phoracantha longicorn beetles are endemic to Australia, and some species have become significant pests of eucalypts worldwide, yet little is known about their host plant interactions and factors influencing tree susceptibility in Australia. Here, we investigate the host relationships of Phoracantha solida (Blackburn, 1894) on four eucalypt taxa (one pure species and three hybrid families), examining feeding site physical characteristics including phloem thickness, density, and moisture content, and host tree factors such as diameter, height, growth, taper, and survival. We also determine the cardinal and vertical (within-tree) and horizontal (between-tree) spatial distribution of borers. Fewer than 10% of P. solida attacks were recorded from the pure species (Corymbia citriodora subsp. variegate (Hook)), and this taxon also showed the highest survival, phloem thickness, relative growth rate, and bark:wood area. For the two most susceptible taxa, borer severity was negatively correlated with moisture content, and positively related to phloem density. Borers were nonrandomly and nonuniformly distributed within trees, and were statistically aggregated in 32% of plots. More attacks were situated on the northern side of the tree than the other aspects, and most larvae fed within the lower 50 cm of the bole, with attack height positively correlated with severity. Trees with borers had more dead neighbors, and more bored neighbors, than trees without borers, while within plots, borer incidence and severity were positively correlated. Because the more susceptible taxa overlapped with less susceptible taxa for several physical tree factors, the role of primary and secondary chemistries in determining host suitability needs to be investigated. Nevertheless, taxon, moisture content, phloem density, tree size, and mortality of neighboring trees appeared the most important physical characteristics influencing host suitability for P. solida at this site.

Spot form of net blotch resistance in barley is under complex genetic control

Key message: Evaluation of resistance toPyrenophora teresf.maculatain barley breeding populations via association mapping revealed a complex genetic architecture comprising a mixture of major and minor effect genes. Abstract: In the search for stable resistance to spot form of net blotch (Pyrenophora teres f. maculata, SFNB), association mapping was conducted on four independent barley (Hordeum vulgare L.) breeding populations comprising a total of 898 unique elite breeding lines from the Northern Region Barley Breeding Program in Australia for discovery of quantitative trait loci (QTL) influencing resistance at seedling and adult plant growth stages. A total of 29 significant QTL were validated across multiple breeding populations, with 22 conferring resistance at both seedling and adult plant growth stages. The remaining 7 QTL conferred resistance at either seedling (2 QTL) or adult plant (5 QTL) growth stages only. These 29 QTL represented 24 unique genomic regions, of which five were found to co-locate with previously identified QTL for SFNB. The results indicated that SFNB resistance is controlled by a large number of QTL varying in effect size with large effects QTL on chromosome 7H. A large proportion of the QTL acted in the same direction for both seedling and adult responses, suggesting that phenotypic selection for SFNB resistance performed at either growth stage could achieve adequate levels of resistance. However, the accumulation of specific resistance alleles on several chromosomes must be considered in molecular breeding selection strategies.

Downstream processing of reverse osmosis brine: Characterisation of potential scaling compounds

Reverse osmosis (RO) brine produced at a full-scale coal seam gas (CSG) water treatment facility was characterized with spectroscopic and other analytical techniques. A number of potential scalants including silica, calcium, magnesium, sulphates and carbonates, all of which were present in dissolved and non-dissolved forms, were characterized. The presence of spherical particles with a size range of 10–1000 nm and aggregates of 1–10 microns was confirmed by transmission electron microscopy (TEM). Those particulates contained the following metals in decreasing order: K, Si, Sr, Ca, B, Ba, Mg, P, and S. Characterization showed that nearly one-third of the total silicon in the brine was present in the particulates. Further, analysis of the RO brine suggested supersaturation and precipitation of metal carbonates and sulphates during the RO process should take place and could be responsible for subsequently capturing silica in the solid phase. However, the precipitation of crystalline carbonates and sulphates are complex. X-ray diffraction analysis did not confirm the presence of common calcium carbonates or sulphates but instead showed the presence of a suite of complex minerals, to which amorphous silica and/or silica rich compounds could have adhered. A filtration study showed that majority of the siliceous particles were less than 220 nm in size, but could still be potentially captured using a low molecular weight ultrafiltration membrane.

Controlled release of ethylene gas from the ethylene-α-cyclodextrin inclusion complex powder with deliquescent salts

Deliquescent calcium chloride (CaCl2) and magnesium chloride (MgCl2) were investigated for their practical application to release ethylene gas from an ethylene-α-cyclodextrin inclusion complexes (CD IC) powder at relative humidities (RHs) between 11.2 and 93.6 % at 18 °C. The IC powder and deliquescent salts were mixed at a ratio of 1:5, respectively. CaCl2 and MgCl2 started to deliquesce at 32.7 % RH. The IC powder dissolved in the concentrated salt solutions to release ethylene gas. Increasing the RH accelerated the release rate. Maximum release of ethylene gas was achieved after 24 h at 75.5 and 93.6 % RH for both IC powder-deliquescent salts mixture. The deliquescent salts proved to be a simple option for releasing ethylene gas from the IC powder.