Screw Worm Fly and Australia

Australia boasts a ‘clean and green’ status and provides a major trading advantage and access to overseas markets – essential to our economy because we export around 75 per cent of our agricultural products.

Screw worm fly is considered to be the most exotic pest threatening Australia’s livestock industries and is endemic in a number of our neighbouring countries to our north. It is one of those pests that could cost close to $500 million a year in lost production and control measures if it entered Australia.

Northern Australia is especially vulnerable to pests that could enter from countries to Australia’s north. The risk of a screw worm fly incursion is low but with the increased movement of people and animals, particularly through illegal entry, heightens the risk of screw worm fly occurring in northern Australia.

An uncontrolled incursion of screw worm fly would severely affect Australia’s livestock industries. Any incursion into Australia will obviously undergo uncontrolled growth until it is detected. The climate in most of northern Australia permits reproduction of this pest throughout the year. For this reason programs for early detection and surveillance are a necessary part of the freedom assurance program.

Australia’s response to detection of a breeding population of screw worm fly is contained within the AUSVETPLAN strategy.

Surveillance programs

Australia’s screw worm fly surveillance border program is delivered by the Commonwealth government through the North Australian Quarantine Strategy (NAQS). This program is designed to minimize the risk of undetected entry of fly struck animals or adult flies from countries to the north of the Torres Strait.

Additional border surveillance is undertaken by trapping for adult flies at sea ports where livestock vessels returning from northern hemisphere destinations pose a very slight risk of carrying adult flies. Two dead flies were found on a single vessel in Darwin harbour in 1988. Livestock vessels are strictly cleaned and inspected prior to docking and the port surveillance program provides an additional level of safety at these sites.

Surveillance for incursions that have crossed the border and established in Australia is undertaken by agriculture departments of the northern states of Australia. Inspections of stock are undertaken at major assembly points such as tick clearance and spelling yards. Animals with obvious fly strike wounds are inspected and samples of fly larvae are submitted for identification.

Page Updated: 20 August 2009