This thesis considers the management of pesticide application dose in Australian orchards and its relevance to the broader issues of pesticide use efficiency and pesticide risk management. Its focus is on pesticide dose management within the context of integrated pest management. It is argued that the currently favoured goal-oriented view of integrated pest management hampers efforts to manage pesticide dose and that a process-oriented view similar to that of total quality management should be promoted. The management of the pesticide application dose has implications for several pesticide use outcomes, namely efficacy, pest resistance, environmental impact, occupational health and safety, consumer health and trade. However there was little systematic data on grower practices in applying pesticides. That which does exist suggested that there is little evidence that the choices of sprayer setup and pesticide rates that growers are currently making are resulting in obvious short-term problems, outcomes or crises. But that there is a potentially serious process problem in disseminating and using information on pesticide rates which is likely to affect both the rates and dosages applied. The achievement of apparently acceptable outcomes from a defective decision process needs further investigation.
The programme of research described in this thesis provides the first systematic research to address this void. A preliminary telephone survey of fifty avocado growers and an in depth field calibration survey of seventy four avocado and macadamia growers on the Sunshine Coast of Queensland showed that the application practices, pesticide rates and applied doses varied very widely. The field calibration data, analysed using a novel but relatively simple spreadsheet, showed that the current legal limits on application rates did not control the dose applied. The analysis also showed that while almost all growers were using low volume spray application and applying less than the equivalent high volume dose (based on an estimated point-of-runoff of 75 litres per 1000 m3 of canopy) many were not using rates which were in accordance with the product labels or off-label use permits. Since these documents are the basis of legal uses it can be concluded that a significant number of growers are using illegal rates. This data is believed to be the first of its kind generated in Australian tree crops.
In-depth semi-structured interviews with a small group of avocado growers were then carried out to determine how growers had arrived at their current practices. These interviews suggested that growers relied heavily on local "expert" advice rather than using rational systematic decision making or rule sets to determine their sprayer setup or mixing rates. This was attributed to the inappropriate directions on many labels and generally poor level of understanding amongst growers of the linkage between components of the orchard spray technology cluster, namely air-assisted spraying, spray volume, spray mixing rate and target dose. These problems were exacerbated by a high level of variation and inconsistency in both product directions and published extension information over the last 15 years. The interviews suggested that while changes in labelling were required, to ensure that "best practice" in spray application was not illegal, these would be unlikely to result in immediate changes in practice because of the current reliance on other sources of information. The data suggested that changes at several levels of the information and regulatory systems would be required if pesticide dose was to be better managed.
An Arena model was selected from several system diagnosis methodologies to describe and analyse the attempts by stakeholders to bring about improvements in label information since 1985, and to plan a new intervention. The Arena model was used to select participants for a Forum, held in May 1998, involving twenty selected Commonwealth, State and industry players. This resulted in a better understanding of the current factors at work within the arena and in the development of several action plans to bring about change. The analysis suggested that commercial and organisational issues, which had not been previously addressed, had impeded changes despite apparent consensus on many technological issues. The Forum process also highlighted the practical difficulties of using an Arena model to manage stakeholder interactions which relied heavily on individual relationships. However despite the failure of one of the key Forum action plans to set up a multi-stakeholder labels working group, the Forum and subsequent report did stimulate the formation of a new joint chemical industry / National Registration Authority working group which included four Forum participants. This group has proposed significant changes to labels for products used in tree crops that are expected to be adopted in October 1999 and which would give both growers and their advisers the flexibility to manage dose more effectively.