Providing practical information to help you protect your farm from biosecurity risks

Minimising spray drift

January 27, 2012

HALSprayDriftMany farmers use a chemical spray to control pests or weeds on their property. Apart from health concerns about exposure to chemicals, one potential issue is the off-target movement (spray drift) of herbicides and pesticides onto nearby plants or susceptible areas.

Potentially sensitive plants may be on your own property or on a neighbouring property. Insect pollinated crops such as orchards rely on beneficial insects like bees. Chemicals used to control insect pests may impact on beneficials, so care needs to be taken that they are not affected by spraying activities.

There is a duty of care for all chemical users and farm owners when conducting chemical applications. If a contractor is used for spraying operations, you still have a responsibility to make sure the spraying is done correctly.

The main points to remember when you are planning to spray are:

  • Read the label.
  • Choose the right chemical for the job.
  • Use the correct application technique.
  • Monitor weather conditions.
  • Keep a record of activities.

Mary O’Brien, a Senior Scientist with BiosecurityQueensland, says that reading and adhering to the label instructions is crucial, especially as labels are updated and may have changed since the last time you used the product.

“Product labels include advice on spray droplet size, no-spray zones and record keeping,” said Ms O’Brien.  “The labels assist users to not only minimise the drift potential from their application but ensure good efficacy of the product they are using. This means saving you money”.

Here are a few tips to consider before spraying:

  • Be aware of the location of neighbours’ crops, the position of buildings, dams, rivers, livestock & other sensitive areas.
  • Establish buffer zones or no spray zones to reduce downwind impacts.
  • Tell neighbours what and when you plan to spray.

Obtain appropriate equipment to measure wind speed and direction, temperature and humidity. These factors play an important role in deciding when to spray. It is important to monitor conditions throughout the application; if conditions become unsuitable, stop spraying.

The way in which the chemical is applied is critical to reducing the spray drift potential. This means using appropriate equipment, using it correctly and applying under the right weather conditions.

Other techniques related to chemical application include:

  • Check your nozzles regularly and choose the correct nozzle for the situation.
  • Calibrate the equipment regularly.
  • Travel at the right speed to achieve good coverage.
  • Minimise the height at which the spray is applied. The higher the release height the greater the possibility for drift.
  • Don’t spray on calm days. Ideally have a constant breeze 3-15 km/hour. Do not spray during inversion conditions which form during the night and early hours of the morning.
  • Always follow personal safety measures to limit your exposure to the chemical.

Mary O’Brien recommends putting as much detail as you can into your records. She follows the 5WH rule when it comes to record keeping, including:

Who – The person who did the spraying and who it was done for.

What – Record the exact chemical name. If possible, include trade name, manufacturer, APVMA number and active ingredient.

Where – Include information that shows the location of the spraying (address, road names, farm name, block numbers, a map).

When – The date(s), start and finish times.

Why – The crop that was treated and reason for treating (broadleaf weeds, insect pest).

How – Weather conditions at the time of application, nozzles used, speed of vehicle, pressure, and any other label requirements.

“The requirements for licensing and record keeping may differ between states and territories so it’s important to know the local regulations that apply to you,” said Ms O’Brien.

“Basically, use good judgement, be responsible and be a good neighbour. And it helps to remember that the regulations are in place to minimise the possibility of off-target damage to crops, including yours.”

For more information, refer to the appropriate government department website in your state or territory or the APVMA.