977 resultados para Weeds, parasitic plants etc


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Biological control of weeds in Vanuatu began in 1935, with the introduction of the tingid Teleonemia scrupulosa to control Lantana camara. To date, nine biological control agents have been intentionally introduced to control eight weed species. Seven of these agents have established on their respective hosts while an eighth, Zygogramma bicolorata, an agent for Parthenium hysterophorus has only recently been released and establishment is unlikely. The fate of a ninth agent, Heteropsylla spinulosa, released for the control of Mimosa diplotricha is unclear. Six other biological control agents, including Epiblema strenuana which was first detected in 2014 on P. hysterophorus on Efate have spread into the country unintentionally. Control of the target weeds range from inadequate to very good. By far the most successful agent has been Calligrapha pantherina which was introduced to control Sida acuta and Sida rhombifolia. The beetle was released on 14 islands and managed to spread to at least another 10 islands where it has effectively controlled both Sida spp. Control of the two water weeds, Eichhornia crassipes by Neochetina bruchi and N. eichhorniae and Pistia stratiotes by Neohydronomus affinis, has also been fairly good in most areas. Two agents, T. scrupulosa and Uroplata girardi, were released on L. camara, and four other agents have been found on the weed, but L. camara is still not under adequate control. The rust Puccinia spegazzinii was first released on Mikania micrantha in 2012 and successfully established. Anecdotal evidence suggests that it is having an impact on M. micrantha, but detailed monitoring is required to determine its overall impact. Future prospects for weed biological control in Vanuatu are positive, with the expected greater spread of recently released agents and the introduction of new agents for P. hysterophorus, L. camara, Dolichandra unguis-cati and Spathodea campanulata.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Cat’s claw creeper vine, Dolichandra unguis-cati (L.) Lohmann (syn. Macfadyena unguis-cati (L.) Gentry) (Bignoniaceae), is a major environmental weed in Australia. Two distinct forms of this weed (‘long’ and ‘short’ pod), with differences in leaf morphology and fruit size, occur in Australia. The long pod form has only been reported in less than fifteen localities in the whole of south-east Queensland, while the short pod form is widely distributed in Queensland and New South Wales. This study sought to compare growth traits such as specific leaf area, relative growth rate, stem length, shoot/root ratio, tuber biomass and branching architecture between these forms. These traits were monitored under glasshouse conditions over a period of 18 months. Short pod exhibited higher values of relative growth rates, stem length, number of tubers and specific leaf area than long pod, but only after 10 months of plant growth. Prior to this, long and short pod did not differ significantly. Higher values for these traits have been described as characteristics of successful colonizers. Results from this study could partly explain why the short pod form is more widely distributed in Australia while long pod is confined to a few localities.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Lantana camara L. is a significant weed of which there are some 650 varieties in over 60 countries or island groups. It has been the focus of biological control attempts for a century, yet still poses major problems in many regions. Lantana has a significant impact on economic and environmental areas and is difficult to control. The key to good management of lantana is constant vigilance. Repeated control of new regrowth is critical to success. Control of new infestations should be a priority because the species is able to expand its range during good seasons, but does not die out during poor conditions. This book is a resource for land managers and researchers on methods of lantana control, particularly biocontrol.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Weed management has become increasingly challenging for cotton growers in Australia in the last decade. Glyphosate, the cornerstone of weed management in the industry, is waning in effectiveness as a result of the evolution of resistance in several species. One of these, awnless barnyard grass, is very common in Australian cotton fields, and is a prime example of the new difficulties facing growers in choosing effective and affordable management strategies. RIM (Ryegrass Integrated Management) is a computer-based decision support tool developed for the south-western Australian grains industry. It is commonly used there as a tool for grower engagement in weed management thinking and strategy development. We used RIM as the basis for a new tool that can fulfil the same types of functions for subtropical Australian cotton-grains farming systems. The new tool, BYGUM, provides growers with a robust means to evaluate five-year rotations including testing the economic value of fallows and fallow weed management, winter and summer cropping, cover crops, tillage, different herbicide options, herbicide resistance management, and more. The new model includes several northernregion- specific enhancements: winter and summer fallows, subtropical crop choices, barnyard grass seed bank, competition, and ecology parameters, and more freedom in weed control applications. We anticipate that BYGUM will become a key tool for teaching and driving the changes that will be needed to maintain sound weed management in cotton in the near future.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Nassella trichotoma (Nees) Hack. ex Arechav. (common name, serrated tussock) occupies large areas of south-eastern Australia and has considerable scope for expansion in the Northern Tablelands of New South Wales. This highly invasive grass reduces pasture productivity and has the potential to severely affect the region’s economy by decreasing the livestock carrying capacity of grazing land. Other potential consequences of this invasion include increased fuel loads and displacement of native plants, thereby threatening biodiversity. Rural property owners in the Northern Tablelands were sent a mail questionnaire that examined use of measures to prevent new outbreaks of the weed. The questionnaire was sent to professional farmers as well as lifestyle farmers (owners of rural residential blocks and hobby farms) and 271 responses were obtained (a response rate of 18%). Key findings were respondents’ limited capacity to detect N. trichotoma, and low adoption of precautions to control seed spread by livestock, vehicles and machinery. This was particularly the case among lifestyle farmers. There have been considerable recent changes to biosecurity governance arrangements in New South Wales, and now is an ideal time for regulators and information providers to consider how to foster regional communities’ engagement in biosecurity, including the adoption of measures that have the capacity to curtail the spread of N. trichotoma.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Wheat occupies a principal place in the diet of humans globally, contributing more to our daily calorie and protein intake than any other crop. For this reason, preventing weed induced yield losses in wheat has high significance for world food sustainability. Herbicides and tillage play an important role in weed control, but their use has often unacceptable consequences for humans and the wider environment. Additionally, the range of herbicides effective on key weeds is dwindling due to the evolution of herbicide resistance. Elevating crop competitiveness against weeds, through a combination of wheat breeding and innovative planting design (planting density, row spacing and orientation), has strong potential to reduce weed-induced yield losses in wheat. The last decade of research has provided a solid foundation for the breeding of weed suppressive wheat cultivars, and continued research in this area should be a focus for the future. In the interim, there is cause for optimism that weeds can be effectively suppressed using existing wheat varieties, through careful cultivar selection and choice of planting design. Further research is required to define the nature of relationships between cultivar traits and competitive planting strategies, across diverse weed flora in multiple countries, sites and seasons. Investment in such innovation promises to produce benefits, not only in terms of sustained wheat yields, but also in terms of human and ecosystem health, through ameliorating chemical and sediment contamination, soil degradation, and CO2 pollution.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mode of access: Internet.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

"R 6-MBS-02-1991"--P. [4] of cover.