Simple steps, systematic approach

There are two leading drivers behind Dick and Gai Marshall’s biosecurity efforts at ‘Woorabinda’ in Berrigan, southern New South Wales: the possible contamination of their non-GM canola production system and weeds affecting sheep and crop production.

The Marshalls say biosecurity is about alert observation and ensuring adherence to practices such as hygiene procedures in order to minimise the risk of threats – diseases, pests and weeds – entering and establishing on-farm.

They grow wheat, barley, canola, peas, lupins and oats along with lucerne and clover pasture for livestock and are keen to keep out weeds that may affect their crop production.

Several weed species are also a concern, although the introduction of the South African Meat Merinos to their flock has been very effective in reducing the impact of key weeds, such as fleabane, as the breed is a non-selective grazer.

Photo of Dick and Gai Marshall

Controlling weeds is a primary motivator
behind Dick and Gai Marshall’s biosecurity
efforts at Berrigan in southern NSW.


Whenever key weeds are spotted on-farm every effort is made to remove them even if it requires several seasons of observation and control. The noxious weed spiny burrgrass is a concern for sheep production at ‘Woorabinda’ and the Marshalls have managed to keep the property free of the weed, which has spread throughout the district.

The Marshalls keep their biosecurity practices simple, but are highly systematic in their application.

Traffic control is an essential part of this. They have an on-farm vehicle for agronomists or other visitors to use to minimise the introduction of local weeds, such as bindii and spiny burrgrass, via tyres.

Farm-hygiene protocols for all contractors require machinery to be washed before it enters the property. If it fails to pass a visual inspection, the Marshalls will request recleaning.

If a contractor’s machinery breaks down on-farm, it is isolated from production areas before being disassembled for repairs, as this process can dislodge soil and plant material including unwanted weed seeds or pests.

Trucks collecting grain enter the property directly from the sealed main road and leave through another exit – a strategy that helps to manage spiny burrgrass, which is often present along the unsealed road.

The Marshalls keep a record of visitors to the property and notify all visitors of farm biosecurity requirements. Visitor parking is restricted to areas around the sheds, which are gravelled. Lanes are also gravelled to minimise the movement of soil on machinery.

The combination of these simple practices stand the Marshalls in good stead for protecting against numerous biosecurity risks, both current endemic pests and exotics that may threaten future crop production.

More information:

Dr Louise Rossiter, NSW grains farm biosecurity officer
02 6391 3188,


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GRDC Project Code NPB00013

Region South, North