4.6.4S
PEST RISK ANALYSIS OF THE RISK OF INTRODUCTION OF FIRE BLIGHT DISEASE VIA TRADE IN APPLES

WP ROBERTS

Department of Primary Industries and Energy, GPO Box 858, Canberra, ACT 2601, Australia

Background and objectives
As an island continent with a relatively short history of developed agriculture, Australia has a relatively lower level of pests compared to other countries. Australia has always taken a conservative position on quarantine risk and this is reflected in the quarantine conditions that Australia requires for the import of a wide range of agricultural commodities.

In the past Australia has not permitted the importation of apples from countries with fire blight because of concerns about the risk of introduction of the disease. A new risk analysis was initiated following an application by New Zealand in late 1995.

Materials and methods
The risk analysis processes used by AQIS require a detailed consideration of all the available scientific and technical information. The process provides for consultation with appropriate experts, Australian States/Territories and any member of the public that may have an interest in the issue. A variety of quantitative and qualitative analysis approaches are being used.

Results and conclusions
An analysis of the situation in Australia indicates that fire blight would be a very significant problem, with some production areas having ideal conditions for disease development and highly susceptible varieties. The history of spread of fire blight shows episodes of little long-distance spread of the disease punctuated by episodes where the disease is introduced into a new area and spreads locally. There is little definitive research on long-distance spread of fire blight, but the most common explanation is that long-distance spread occurs through the introduction of contaminated planting material. There is substantial research work indicating that apples can carry viable bacteria even from orchards where symptoms are not very evident. There is at least one report that implicates fruit in the long-distance spread of fire blight.

The risk analysis processes used by Australia will be presented in the context of an analysis of the risk of introduction of fire blight via trade in apples.