Why do pesticides need to be managed?

Growers rely on pesticides for productive crops, with insecticides targeting destructive insects such as sugarcane grubs, and herbicides, like diuron, used to control weeds. Pesticides are typically synthetic chemicals that are not naturally present in the environment. Given the nature of these chemicals, plants and animals can be harmed if they reach waterways in elevated concentrations.

Extensive monitoring from scientists and extension staff has shown certain pesticides are often found in coastal waterways, sometimes at levels that exceed ecosystem protection guidelines.

These pesticide concentrations are typically the highest in local waterways, as well as freshwater ecosystems and inshore seagrass meadows close to the shoreline.

How are pesticides lost off paddocks?

Scientists and extension staff now have a good understanding of how common pesticides move and their toxicity in receiving waterways.

Pesticides can be lost off the farm into the environment through spray drift, mixing site spills, flushing and cleaning spray tanks, deep drainage and paddock runoff.

The intricate network of connected streams, wetlands, and groundwater intensifies these challenges, facilitating the movement of runoff between these waterways.

Practices to manage pesticides

Growers are adopting innovative methods to reduce off-paddock pesticide losses through careful product selection, application techniques, and timing of applications. Some of these practices include:

• Upgrading spray equipment to the latest drift reduction nozzles and application technology.
  

• Using precision technology for targeted and reduced pesticide application.
  

• Exploring 'alternative herbicides' that offer equal efficiency but are less prone to runoff and pose lower ecological risks to the receiving environment.
  

• Undertaking specialised spray training and professional development activities.
  

• Hosting demonstration sites and participating in farm runoff monitoring.
  

  
  

Improvements in pesticide levels

There is water quality evidence that demonstrates year-to-year improvements based on actions from growers in changing their land management practices.

Encouragingly, early monitoring data indicate a decreasing trend in imidacloprid concentrations at some streams over recent years, which is likely a testament to targeted extension efforts and farm management improvements.

As imidacloprid is a critical insecticide for the sugarcane industry, a proactive industry-wide management strategy is recommended to ensure its long-term future.