In this article, Teagasc’s Mary Roache, ASSAP Advisor Mayo, discusses tackling rushes on your farm and MCPA.
In 2020, MCPA, commonly used to control rushes, was responsible for 46 out of 91 detected pesticide breeches.
MCPA is water-soluble; it does not bind to soil particles and, therefore, more prone to leaching and run-off to nearby waterbodies.
Add to this, the fact that rushes thrive in poorly drained areas with a water table near the surface. You can see why run-off can potentially occur.
Remember a single drop of pesticide lost to a water body such as a typical small stream (1 meter wide, 0.3 meters deep), for example, can be enough to breach the legal limit for pesticides along 30km of its length.
It is not necessary or sustainable to constantly apply sprays, and they should not be looked on as the primary method to control weeds.
Furthermore, the presence of rushes in a field do not make the field ineligible for payment once it is being grazed.
Some non-chemical methods of control:
- Firstly, good grazing management and appropriate stocking rates;
- Taking a soil test and applying nutrients required.
- Appropriate drainage if required;
- Lastly, the use of a topper/mower for weed control.
To minimise spray drift with MCPA products, consider using low drift nozzles or switch to using Glyphosate products in a weed licker instead.
Always ensure you:
- Check the weather forecast – there should be no heavy rain forecast for 48 hours;
- Secondly, ground conditions are good and dry with no standing water in the field;
- Thirdly, ensure rates of application are not exceeded;
- You use the correct method of application (e.g. only boom sprayer for MCPA);
- There are calm conditions if applying a product using a boom sprayer;
- Observe buffer zones (e.g., a 5m buffer zone for MCPA);
- Ensure you triple rinse empty containers before being disposed of properly;
- You never fill your sprayer from a watercourse.
Tackling rushes on your farm: Advice on MCPA from Teagasc:
- Cutting rushes can offer good levels of control, but must be repeated regularly;
- Spraying with products based on MCPA is cost-effective, but care must be taken to protect vulnerable water sources.
- Seek qualified advice before spraying;
- Only use approved products at recommended rates;
- Read the label – not for use in Knapsack sprayers or weed lickers;
- Avoid spillage of product or water when filling;
- Ensure you test the sprayer;
- Pace out 5-meter buffer area;
- Spray on a calm day to avoid drift;
- When finished spraying, thoroughly wash the sprayer inside and outside, keeping a safe distance from all watercourses;
- Complete records of use on the day of spraying.