By University of Sydney professor of plant pathology Dr David Guest.

Australian agriculture, horticulture and its unique natural environments remain free of many devastating pests and diseases because of its geographic isolation and historically strict quarantine regulations. Freedom from pests and diseases means lower production costs, fewer pesticides, health benefits for growers and consumers, and access to overseas markets.

Successive Australian governments have been strong advocates of the benefits of free trade. However, significant risks to environments and industries are now appearing as a result. In the past 18 months Australia has seen the introduction of eucalyptus rust, chestnut blight and the Asian Honeybee, each with potentially devastating consequences. In 2010 alone 26 exotic pests and pathogens escaped into the state of Queensland.

While the benefits of free trade are obvious from a simplistic economic point of view, the biological reality is that free trade will only be safe once all pests and diseases become evenly spread across the globe. Have we reached the point where the benefits of free trade are outweighed by the biosecurity threats it poses? Has the time come to question the impact of free trade on Australian and global food security? What are nations prepared to sacrifice in food production and environmental integrity in the interests of short-term and short-sighted economic and strategic interests?

As a signatory to the World Trade Organization (WTO), Australian trade in food, animals and plants is regulated under the Sanitary and Phytosanitary Measures Agreement (SPS).  While countries set their own biosecurity standards, trade restrictions must be based on science, must not discriminate between countries and can only be applied to protect human, animal or plant life or health.

Before plants or animals are imported into Australia, Biosecurity Australia conducts a detailed, science-based pest risk analysis to determine “acceptable levels of protection” that minimise risks posed by exotic pests and diseases. This analysis and its recommendations are scrutinized by expert and public discussion before an import permit can be granted and trade is allowed. Responsibility for implementing phytosanitary regulations then falls to the Australian Quarantine and Inspection Service (AQIS).

There are two fundamental flaws in this process. Firstly, pathogens and pests are incredibly abundant – most microorganisms produce millions of infective proagules on an infected host daily – so that even an extremely low level of probability becomes an eventual inevitability. Is the concept of an “acceptable level of protection” against exotic pests and diseases defensible, or is it just biological nonsense?

The second flaw is that “science-based” means that only published scientific evidence can be used in the pest risk analysis. This means that only pests and pathogens known to cause disease on Australian plants elsewhere in the world can be considered during the risk analysis. Of course, there are few published studies on the impact of exotic pests and diseases on the vast inventory of Australian native plants, so the current pest risk analysis methodology usually concludes that there is no potential impact.

The only real way to find out what the impact would be is to introduce the pest and see what happens – one such massive uncontrolled, but irreversible, experiment is currently underway in Australia testing the effect of eucalyptus rust on native flora and dependent fauna. In almost every field of science, medicine and engineering this default “presumption of innocence” has been relegated to the historic dustbin and has been replaced by a precautionary principle that requires scientific evidence to show that something does not cause harm before it is accepted.

While the SPS includes a “precautionary principle” that allows temporary restrictions on trade to facilitate scientific studies where such uncertainty exists, the scientific capacity or funds do not exist to screen tens of thousands of plant species against potential pests and diseases in the very short time allowed. It is just a matter of time before global agriculture faces a level playing field with regards to pests and diseases. The underinvestment in funding and capacity in science and quarantine means this will happen sooner rather than later.

Although phytosanitary regulations should not discriminate between nations, free trade is compromised by the political process. Australia currently allows apple imports from China, where fireblight is a problem for growers. However apples can only be imported from orchards in provinces free from quarantine pests including fireblight, and must be handled and inspected rigorously to reduce the biosecurity risk below Australia’s ALOP (Acceptable Level of Protection). However, apples can be imported from any part of New Zealand and normal orchard practice there is deemed adequate, despite the fact that fireblight is endemic and widespread. Why the apparent discrimination against Chinese apples?

Are the benefits enjoyed by current and future generations of Australians being compromised by a lack of scientific insight and long term vision? What grower wants to compete in a market where all pathogens and pests are equally distributed across the globe? The time has come for Australia and other nations to reconsider the impact of the WTO on agriculture, horticulture and our environments before it is too late.

Dr David Guest would like to acknowledge the assistance of Dr Andre Drenth from the University of Queensland and Dr Rose Daniel from the University of Sydney in preparing this column.

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