Mixed cropping and TR4

By Deanna Belbin

Growers that undertake mixed cropping on their properties are reminded that biosecurity measures should be followed for all cropping areas.

Minimising the risk of spread of all pests, diseases and weeds specific to each crop is not only sound farm management, but also part of your general biosecurity obligations.

Having a robust farm biosecurity plan across all cropping areas and being prepared is vital to minimise the disruption to your farming operations if a serious biosecurity issue is detected.

For example, a Panama disease tropical race 4 (TR4) infected banana block on a mixed crop property has the potential to contaminate other farm areas.

Where a ‘Notice of presence of Panama disease tropical race 4’ has been given to you, any land exposed to the unrestricted movement of soil, banana plants, machinery, and other carriers will be placed under Panama movement controls.

Any potential carriers of Panama TR4 must then be cleaned and decontaminated prior to moving off the affected property.

To reduce the risk of cross-contamination between blocks, you should consider implementing procedures to separate the operations between different cropped areas, with their own pools of machinery and equipment.

This will limit the amount of required machinery decontamination should Panama TR4 or any other pest or disease appear on your property.


Dividing a farm into separate areas or zones, is a cost-effective way for you to control the movement of vehicles, machinery and equipment between zones and within zones.

An effective farm zoning plan usually incorporates three main zones:

  • an exclusion zone to exclude all nonessential vehicles
  • a separation or clean zone, such as a clean roadway, to ensure essential vehicles that come onto the farm, such as fruit pick up or fuel delivery do not bring or take contaminants with them a ‘farm activity’ or ‘dirty’ zone where farm vehicles, machinery, equipment or tools appropriately decontaminated on entry and exit.

If your business can demonstrate that specific areas of a mixed cropping property have not been exposed to banana plant material or soil in which banana plants may be grown, and therefore has not been exposed to Panama TR4, you can consider those areas to be ‘clean zones’.

Keeping a register of vehicles, machinery, staff movements, and decontamination procedures is important to assist trace investigations should an area be infected with a disease.

The information can help determine the extent of the area exposed to the risk and prevent further disease spread.

Biosecurity Queensland can provide technical support to growers on proposed mixed cropping ventures and assist with the implementation of a farm biosecurity plan and farm zoning plan.

Phone 13 25 23 for more information or visit biosecurity.qld.gov.au