The additive effect of a stem galling moth and a competitive plant on parthenium weed under CO2 enrichment

Parthenium weed (Parthenium hysterophorus) is a highly invasive plant that has invaded many parts of world including Australia. The present study reports on the effects of rising [CO2] on the performance of one of its biological control agents, stem-galling moth (Epiblema strenuana) when combined with a competitive plant, buffel grass (Cenchrus cilliaris). The study was carried out under controlled environment facilities during 2010–11. P. hysterophorus when grown under elevated [CO2] of 550 µmol mol−1, produced a greater biomass (27%), attained greater stature (31%), produced more branches (45%) and seeds plant−1 (20%), than those grown at ambient [CO2] of 380 µmol mol−1. Buffel grass reduced the biomass and seed production of P. hysterophorus plants by 33% and 22% under ambient [CO2] and by 19% and 17% under elevated [CO2], respectively. The combined effect of buffel grass and E. strenuana reduced dry biomass and seed production by 42% and 72% under ambient [CO2] and 29% and 37% elevated [CO2], respectively. Although the suppressive effect was different between ambient and elevated [CO2], the effect is likely to be retained. Stem gall formation by E. strenuana significantly enhanced the lateral branch production in plants grown under both [CO2]. Epiblema strenuana did not reduce the seed production of P. hysterophorus under the elevated [CO2] nevertheless, our earlier study had confirmed that many of the seeds produced under such conditions are not filled. This study has highlighted that the additive suppressive effect of E. strenuana and buffel grass on P. hysterophorus growth would be retained under future atmospheric CO2 enrichment

The additive effect of a stem galling moth and a competitive plant on parthenium weed under CO2 enrichment

Parthenium weed (Parthenium hysterophorus) is a highly invasive plant that has invaded many parts of world including Australia. The present study reports on the effects of rising [CO2] on the performance of one of its biological control agents, stem-galling moth (Epiblema strenuana) when combined with a competitive plant, buffel grass (Cenchrus cilliaris). The study was carried out under controlled environment facilities during 2010–11. P. hysterophorus when grown under elevated [CO2] of 550 µmol mol−1, produced a greater biomass (27%), attained greater stature (31%), produced more branches (45%) and seeds plant−1 (20%), than those grown at ambient [CO2] of 380 µmol mol−1. Buffel grass reduced the biomass and seed production of P. hysterophorus plants by 33% and 22% under ambient [CO2] and by 19% and 17% under elevated [CO2], respectively. The combined effect of buffel grass and E. strenuana reduced dry biomass and seed production by 42% and 72% under ambient [CO2] and 29% and 37% elevated [CO2], respectively. Although the suppressive effect was different between ambient and elevated [CO2], the effect is likely to be retained. Stem gall formation by E. strenuana significantly enhanced the lateral branch production in plants grown under both [CO2]. Epiblema strenuana did not reduce the seed production of P. hysterophorus under the elevated [CO2] nevertheless, our earlier study had confirmed that many of the seeds produced under such conditions are not filled. This study has highlighted that the additive suppressive effect of E. strenuana and buffel grass on P. hysterophorus growth would be retained under future atmospheric CO2 enrichment

Early recovery signs of an Australian grassland following the management of Parthenium hysterophorus L.

Parthenium weed (Parthenium hysterophorus L.) is believed to reduce the above- and below-ground plant species diversity and the above-ground productivity in several ecosystems. We quantified the impact of this invasive weed upon species diversity in an Australian grassland and assessed the resulting shifts in plant community composition following management using two traditional approaches. A baseline plant community survey, prior to management, showed that the above-ground community was dominated by P. hysterophorus, stoloniferous grasses, with a further high frequency of species from Malvaceae, Chenopodiaceae and Amaranthaceae. In heavily invaded areas, P. hysterophorus abundance and biomass was found to negatively correlate with species diversity and native species abundance. Digitaria didactyla Willd. was present in high abundance when P. hysterophorus was not, with these two species, contributing most to the dissimilarity seen between areas. The application of selective broad leaf weed herbicides significantly reduced P. hysterophorus biomass under ungrazed conditions, but this management did not yet result in an increase in species diversity. In the above-ground community, P. hysterophorus was partly replaced by the introduced grass species Cynodon dactylon L. (Pers.) 1 year after management began, increasing the above-ground forage biomass production, while D. didactyla replaced P. hysterophorus in the below-ground community. This improvement in forage availability continued to strengthen over the time of the study resulting in a total increase of 80% after 2 years in the ungrazed treatment, demonstrating the stress that grazing was imposing upon this grassland-based agro-ecosystem and showing that it is necessary to remove grazing to obtain the best results from the chemical management approach

Germination behaviour of Avena sterilis subsp. ludoviciana under a range of light and temperature regimes

Context: Avena sterilis subsp. ludoviciana (wild oats) is one of the major winter weeds of the Northern Grains Region of Australia. The abundance of this weed increased dramatically after the adoption of no-tillage conservation agriculture (NTCA). However, information is lacking on the germination characteristics of the two types of seed (i.e. primary and secondary) that it produces.Aims: We aimed to determine the light and temperature requirements for germination and the time to germination of primary and secondary seeds of A. ludoviciana, in order to find ways to manage this weed effectively under NTCA systems.Methods: Primary and secondary seeds and caryopses from two southern and two northern biotypes were exposed to a range of temperature and light regimes in the glasshouse, and germination was assessed.Key results: All biotypes had ∼25% higher germination from primary than secondary seeds. Removing the hull increased caryopsis germination by ∼70%. The use of a light/dark photoperiod stimulated germination of both types of seed and caryopses compared with continuous darkness. Based on data for caryopses, 7°C and 9°C were found to be optimal germination temperatures for southern and northern biotypes, respectively. At optimum germination temperature, primary caryopses germinated 7–20 days earlier than secondary caryopses. In addition, a light/dark environment resulted in germination 2–6 days earlier than continuous darkness.Conclusions: In the Northern Grains Region, seeds retained on or close to the soil surface (i.e. in NTCA systems) can undergo maximum germination during May–June (late autumn–winter), when long-term average temperatures match optimum germination temperatures. This coincides with winter crop plantings.Implications: The seasonal timing of germination and the difference in germination timing between primary and secondary seeds, which help to stagger emergence of this weed, are major issues that need to be addressed in NTCA systems

The combined effect of biological control with plant competition on the management of parthenium weed (Parthenium hysterophorus L.)

Parthenium hysterophorus L., (Asteraceae) commonly known as parthenium weed, is a highly invasive plant that has become a problematic weed of pasture lands in Australia and many other countries around the world. For the management of this weed, an integrated approach comprising biological control and plant competition strategies was tested in southern central Queensland. Two competitive pasture plant species (butterfly pea and buffel grass), selected for their high competitive ability, worked successfully with the biological control agent (Epiblema strenuana Walker) to synergistically reduce the biomass of parthenium weed, by between 62 and 69%. In the presence of biological control agent, the corresponding biomass of competitive plants, butterfly pea and buffel grass increased in comparison to when the biological control agent had been excluded, by 15 and 35%, respectively. This suggests that biological control and competitive plants can complement one another to bring about improved management of parthenium weed in Australia. Further, this approach may be adopted in countries where some of the biological control agents are already present including South Africa, Ethiopia, India, Pakistan and Nepal

Biology, propagation and utilization of elite coconut varieties (makapuno and aromatics)

Coconut farming is not only a vital agricultural industry for all tropical countries possessing humid coasts and lowlands, but is also a robust income provider for millions of smallholder farmers worldwide. However, due to its longevity, the security of production of this crop suffers significantly from episodes of natural disasters, including cyclone and tsunami, devastating pest and disease outbreaks, while also affected by price competition for the principal products, especially the oil. In order to reduce these pressures, high-value coconut varieties (makapuno and aromatics) have been introduced in some regions, on a limited scale, but with positive outcomes. Even though these two varieties produce fruit with delicious solid or flavoursome liquid endosperm, their distinct biochemical and cellular features unfortunately prevent their in situ germination. In fact, embryo rescue and culture have been developed historically to nurture the embryo under in vitro conditions, enabling effective propagation. In an attempt to provide a comprehensive review featuring these elite coconut varieties, this paper firstly introduces their food values and nutritional qualities, and then discusses the present knowledge of their biology and genetics. Further possibilities for coconut in general are also highlighted, through the use of advanced tissue culture techniques and efficient seedling management for sustainable production of these highly distinct and commercially attractive varieties of coconut

Challenging the field: Bourdieu and men's health

©2014 Macmillan Publishers Ltd. This article considers how understandings of health promotion with men may be assisted by engagement with Bourdieu's theoretical work. The article outlines leading concepts within Bourdieu's work on 'field', 'habitus' and 'capital'; considers subsequent critical debates among gender, feminist and sociological theorists around structure and agency; and links these to discussions within men's health. A particular focus concerns structural disruption of, and movement of social actors between, 'fields' such as family, work and leisure settings. The article examines, through Bourdieu's critical legacy, whether such disruption establishes conditions for transformative reflexivity among men in relation to previously held dispositions (habitus), including those inflected by masculinities, that affect men's health practices. Recent work within Bourdieu's heritage potentially facilitates a re-framing of understandings of men's health practices. The article specifically explores masculine ambivalence within accounts of reflexivity, identities and practice, and considers how social and symbolic (masculine) capital are in play. Implications of Bourdieu's leading concepts for theorising settings-focused approaches to men's health promotion are exemplified with reference to a men's health project in a football stadium leisure setting. The article considers the benefits and challenges of applying gendered critical insights drawing on Bourdieu's work to men's health promotion, and discusses emerging theoretical dilemmas