Impact of exotic insect invasions on Australian agriculture, and the need for biosecurity and quarantine

Incursions of exotic plant pests threaten the economic viability of Australia’s plant industries, which have a farm gate value of $Aud19 billion and contribute at least $Aud12 billion to export income. Many thousands of plant pests are intercepted at Australian borders each year, but most do not become established. Many of those that establish have only minor impact, while others spread and require significant government and industry resources to eradicate. An incursion of Papaya fruit fly, Bactrocera papayae, cost $Aud35 million in direct eradication costs, and the cost of the ongoing eradication campaign of Red Imported Fire Ant, Solenopsis invicta, is so far over $Aud200 million. The value of market access lost through the detection of exotic plant pests can also be very high. Endemic plant pests can invade regions where they are not normally present. The value of horticultural markets protected by declarations of area freedom from pests is estimated at over $Aud500 million a year. This is achieved mainly by keeping areas free of fruit flies and especially Queensland fruit fly, Bactrocera tryoni, an endemic species. All industries are threatened by incursions of exotic plant pests. The aim of biosecurity, quarantine and related research is to prevent their entry to Australia and establishment, and if they do become established to restrict their rate of spread and try to eradicate them before substantial losses occur. The cost of eradication is predicted to increase almost exponentially with time following successful establishment.