[ASC-media] Media Release: Climate change poses plant threat

JCA Media jca.media at starclass.com.au
Thu Sep 14 05:01:24 CEST 2006


Council of Australasian Weed Societies and the Weed Management Society of SA
15th Australian Weeds Conference, Adelaide, 24-28 Sept 2006

Media release 14 Sept 

CO2 AND TEMPERTURE RISE TO INCREASE WEED PROBLEMS

With the cost of weeds in Australia hitting $4 billion a year - and that's not counting the cost to the environment - 450 scientists and land managers from around the world are gathering in Adelaide during 24-28 Sept for the 15th Australian Weeds Conference. 

To be opened on Monday 25 September by the Hon. Eric Abetz, Minister for Fisheries, Forestry and Conservation, the biennial conference this year has the theme Managing Weeds in a Changing Climate.  

Addressing the theme, invited speaker Dr Peter Hayman from the SA Research and Development Institute (SARDI) warned that rising levels of CO2 and higher temperatures are set to increase weed problems. 

'Farmers face an array of changes cascading from the global climate shift that will require a whole range of adaptive management measures on the ground', Dr Hayman said. 

For examples, models run by CSIRO suggest a warmer wetter world, but a drier southern Australia.

'In general terms the strongest drying indications are for spring, followed by winter and then autumn, with summer rainfall trends less certain. But even the lower end of global warming is likely to further reduce the opportunities for spraying summer weeds.' 

Other effects are likely to be quite subtle. For example, a study by Dr Victor Sadras of SARDI showed that even a very small, statistically undetectable increase in temperature of about 0.02°C per year is sufficient to cause significant shortening of time to flowering and season length in wheat. Changes in temperature are likely to change the timing of emergence and growth of both weeds and crops. 

Higher temperatures have also been observed to reduce herbicide persistence, which may complicate weed control in autumn and winter. 

However, drier summers could slow down herbicide degradation in some areas leading to carry-over problems. 

One of the few positives of climate change is that increased CO2 is likely to make crops yield more and this may provide some compensation to farmers for hotter drier conditions associated with the early stages of climate change. 

However increased CO2 will also increase weed growth and may make some weeds harder to control, so weed management will be one of the most important ways for farmers to cope with climate change. 

'Obviously there is some uncertainty in how all these changes will play out at farm level', Dr Hayman said. 'A lot will depend on local conditions and the farming systems in place. However, one can see that there is plenty of room for good adaptive management to deal with the changes ahead.'

Dr Hayman said that close collaboration between industry and researchers will be even more important in coming years as the farming sector sorts through the changes it needs to make in weed management to stay productive and competitive.  

As well as the new set of best practice manuals for several WONS (Weeds of National Significance) to be launched by the Minister, topics covered in different sessions in the conference include:
Animal-dispersed weeds	
Regional weed management
Aquatic and riparian weeds	
New chemicals 
Pasture weeds	
Economics of weeds
The biology and ecology of crop weeds	
Environmental weeds
Weeds and mines	
Weed risk management
Herbicide resistance	
Social and policy change
Biocontrol	
Community participation 
Weed eradication 	

Keynote international speakers include Professor Harold A Mooney of Stanford University, USA; Professor David M Richardson, of the DST-NRF-Centre of Excellence for Invasion Biology University of Stellenbosch, South Africa; Hansjoerg Kraemer, Bayer CropScience, Germany; and Bob Blackshaw, Agriculture and Agri-Food Canada.

Other stories emerging from the 260 papers and posters include:

*	Wild radish can cut lupin production by 66%
*	A two-fold increase in grain yield achieved in WA by control of ryegrass with mouldboard ploughing 
*	Stock and machinery can spread branched broomrape
*	A new report shows 133 weed species threaten 432 species of native plants and animals in NSW
*	Biocontrol kicking in at last against mimosa and mesquite 
*	Camels reduce parkinsonia pods per tree from 3800 to 1
*	Para grass knocks out wild rice, the staple food for magpie geese
*	Call for northern gardeners to avoid popular ornamental Murraya 
*	Economic analysis of weed R&D shows return on investment over 25 years is 56:1 - but we have to hang in there for the long haul to get the gains
*	Feral apple trees foil reduction in pesticide use in Adelaide Hills 
*	Local families take on feral cactus in the Flinders Ranges

Contacts:
Conference Chairs: Dr John Virtue 08-8303 9502; Dr Chris Preston 08-8303 7237
Dr Peter Hayman 08-8303 9729 
General media contacts: Mr Peter Martin 08-8303 6693, 0429 830 366; Rita Reitano 08-8303 6857, 0419 184 153
Weed images available from Weeds CRC: rita.reitano at adelaide.edu.au
Conference web site: www.plevin.com.au/15AWC2006/




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