Best Practice use of pesticides

Monitoring of drinking water in Ireland continues to detect exceedances above the standard for certain herbicides. The chemicals causing greatest problems are MCPA (Agritox, Mortone, etc) and 2,4-D (Bandock EW, Mortox 50 etc). They are highly soluble in water. Kieran Kenny ASSAP Advisor has more

The chemicals causing the greatest problems are MCPA (Agritox, Mortone, etc) and 2, 4-D    (Bandock EW, Mortox 50 etc). They are highly soluble in water, more persistent in the environment and widely used. Two other herbicides with high usage and causing increasing concern are Glyphosate (Roundup, Gallup etc) and Triclopyr (Grazon Pro, Garlon Ultra etc). These four herbicides accounted for 78% of the total exceedances in 2020.

How to minimise the impact on water bodies

Implementing best management practice is the best mitigation advice:

1. Storage and Preparation for Spraying:

• The store should be secure, warning sign at entrance, potential leakages retained and labels still attached on original containers.
• The applicator must be a trained Professional Pesticide User.
• Application equipment must be well maintained, calibrated and tested every 3 years.
• Discuss with your adviser alternative methods of control such as, topping, drainage, soil fertility and sward improvement.

2. Handling Herbicides

• Use appropriate Personal Protective Equipment (PPE) - Check safety data sheet.
• Minimise risks during transport as accidents can happen.
• Always read and follow label instructions (correct use, correct rate, correct time).
• Always use the approved application method for the chemical. Where appropriate the safest option is spot spraying as it reduces the volume of chemical used.
• Take care to avoid spills, especially when handling the concentrated product. Useful to have a containment system in place to catch spills.
• Sprayers should be filled where losses to water bodies cannot occur. NEVER fill the sprayer directly from a watercourse.

3. Spraying Herbicides

• Be aware of the location of water bodies on the farm. Take note of the Buffer Zone on the chemical label (generally 5m for grassland herbicides).
• Comply with Safeguard Zones for the protection of drinking water abstractions.
• Do not apply close to vulnerable areas such as karst bedrock, swallow holes or field drains filled towards the surface with stone.
• Spray when conditions are suitable: calm day, vegetation dry, no heavy rainfall for >2 days, land dry (no tyre marks) and a young crop of healthy weeds.
• Triple rinse the container and add the rinsate to the sprayer.
• In the field, spray off the tank washings and clean down the external parts of the sprayer. Do not discard sprayer washings on a yard or gravel area as it can potentially enter a water body.

In the video below, Kieran Kenny, Teagasc ASSAP Advisor goes through how to minimise the impact of pesticides on water bodies.

For more information see Water Quality Week