Implications for technology transfer
A preliminary step to breaking the epidemic cycle of disease in plant populations is to identify strategic intervention points in the life cycle of the agent, ttis requires a thorough knowledge of characteristics relating to the crop or plant population itself (host), the pathogen (disease-causing agent) and the place in which the disease occurs (environment). While epidemiological study based on these characteristics can yield great insights as to the establishment and continuation of disease in plant populations, observations may be very specific to time and place and for this reason great circumspection is required when transferring conclusions and hence control strategies from one region to another.
Agrometeorological factors may vary considerably, as evidenced when early European farming traditions were first imported to Australia, tte intensive cropping system used on European farms and originally imported into Australia and other Asia-Pacific countries has been found in many cases to be unsuitable in terms of available area and soil characteristics. Disease control approaches for intensive horticulture may also be unsuitable for broad acre field crops, for example the practice of liming soil to pH 7.0-7.5 to control clubroot (Plasmodiophora brassicae) of Brassica spp. (Donald et al. 2003).
Large scale migration from Europe to Australia from the early 19th century brought farmers into contact with semi-arid and arid environments for the first time, tte response was to perceive drought as a symbolic national enemy, and to attempt technological solutions to solve the "drought problem" with extensive economic support. A better approach might have been to accept that certain areas of the land were simply unsuitable for certain types of agriculture (Royal Geographical Society of Queensland 2001).
Relevance of specific technologies also changes with time. Tillage was traditionally used in Australia to reduce the incidence of soil borne diseases including S. sclerotiorum, but improved conservation practice suggests that zero tillage is desirable in conserving soil moisture, reducing erosion and limiting costs (Kharbanda and Tewari 1996; Paulitz 2006). Furthermore, a number of studies on conventional and no-till systems have not found significantly different levels of disease incidence (Paulitz 2006). To support place-sensitive technology transfer throughout the Asia-Pacific region, Australia is developing a range of generic modeling and intervention strategies which will be validated at selected sites in the region. An important component of this ongoing research thrust, however, is the securing of funding from regional agencies to augment support which the Australian government is prepared to commit to such a project.
Australia offers a range of research experience relating to an integrated monitoring system which sees regularly updated fact sheets for disease control distributed to farmers throughout State Agriculture Departments (such as the NSW Department of Primary Industries, http://www.dpi.nsw.gov.au), based on modelling studies supported in government and universities by funding bodies such as Grains Research Development Corporation (http://www.grdc.com.au).
Resource allocation for risks
A rational allocation of resources for the control of plant diseases is based on the potential economic losses which they may cause, ttis applies both at individual level, when a grower decides whether or not control of a particular disease is financially warranted, and at the national level, when funds are apportioned to research, risk communication and disease control. As the disease spectrum and economic environment change with time, estimates of disease losses need to be based on current data, if resource allocation is to be optimized (Brennan and Murray 1998).
In countries where primary industries are in an early stage of development, farmers may have little income and may rely on loans at high interest rates for input investments, and for crop protection. When there is crop failure due to high climatic variability, as may result in droughts, farmers with low financial capacity may loose their entire investment. Ultimate outcomes are not only economic; farmers in India have been reported to perceive this as personal failure and widespread anguish with high rates of suicide has been recorded (Sivakumar 2000). In
Australia the suicide rate in male farm owners is about twice the crude national average for males in all sectors, despite the fact that in Australia several organizations provide farmers with financial assistance when extreme weather conditions have resulted in severe challenges, such as drought and floods.
Such assistance includes income support from Centerlink, interest subsidies from the Rural Assistance Authority, advice and funding for developing a business plan and succession planning from the Farm Help Program, and funding for establishment of a farm Environmental Management System (EMS) from various state agencies. In order to further the mental health and wellbeing of farmers in NSW, Australia, a blueprint has been developed to improve access to mental health support, including counselling, crisis lines and the teaching of coping skills (NSW Farmers Association 2005).
While applied IPM is likely to remain a technological area, resource allocation within a risk management framework needs to involve interdisciplinary collaboration if the very real threats to the mental and physical health of those engaged in farming as primary industry are to be addressed.
Supportive Decision-Making Tools
A decision support tool called RustMan was developed for stripe rust of wheat in the 1990s. RustMan estimates the likely impact that stripe rust will have on wheat yield and the benefits from spraying to control the disease. RustMan uses results derived from field experiments at Wagga Wagga and Yanco from 1984-1987, with the addition of current information on the reaction of wheat varieties to the races of stripe rust in Southern and Central NSW. Estimates require the input of average weather conditions occurring over one agricultural season (Gordon Murray, personal communication, 2006).
Sufficient macroclimatic data have now been collected for the development of a similar tool for Sclerotinia rot on canola although the higher impact of post-treatment climatic variation demands a longer-term forecast record.
Effectiveness of decision-making tools tte effectiveness of decision making tools depends on their ability to predict and to facilitate risk management or mitigation, with subsequent assessment of outcome (Meinke and Stone 2005). Some points relating to this effectiveness are:
• Farmers are only able to respond and adapt to climatic conditions, they cannot expect the model to assist them to manage or mitigate the climatic event itself,
• Adaptation or 'responsive adjustment' as risk ameliorating strategy, must be targeted and may be complex,
• tte proactive dimension in risk amelioration is important if damage is to be minimised,
• Outcomes need to be seen in practical terms if individual and societal benefits through improved risk management practices and better targeted policies are to be optimised.
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