Thistle Control in Established Grassland
Thistle Control in Established Grassland
Over 200,000 ha of grassland in Ireland is infested with thistles.
- Thistles are more common in:
- old swards (9-20 years old)
- low P, N, high K soils
- beef and sheep more than dairy enterprises
- grazing swards, particularly if over- or under-grazed
- The area taken up by weeds is not available for grazing
- They compete with grass for water, nutrients and light
- Thistles in hay and silage results in lower utilisation and increased wastage
- Lower grazing pressure means lower yielding weed grasses will increase, leading to sward deterioration
- Animals will not graze close to thistle plants
- Thistles can cause mouth lesions in grazing sheep, increasing the risk of highly contagious infection
Economical long-term control of thistles in established grassland can be achieved using Forefront*, Pastor* or Thistlex* herbicides.
Make sure the thistles are at the correct growth stage - the rosette stage - in order for them to take in the chemical properly and for it to translocate down into the roots. If they are too big then cut them and treat the regrowth, usually 2-3 weeks later.
For spot treatment around the farm to stop thistles from spreading their seeds, use Grazon* 90, which will not only kill the thistles but docks and nettles as well.
| Contents |
30 g/litre aminopyralid
100 g/litre fluroxypyr |
Apply at the rosette growth stage, before thistles are 250mm high or across |
| Pack Size |
2.0 litres |
| Dose Rate |
2.0 litres/ha |
| Water volume |
200-300 l/ha |
The weeds must be actively growing.
Leave 2-3 weeks after cutting/grazing to allow sufficient regrowth before spraying.
After application allow:
- 7 day grazing interval before returning stock to treated areas
- 7 days before mowing for maximum translocation
| Contents |
50 g/litre clopyralid
75 g/litre fluroxypyr
100 g/litre triclopyr |
Apply at the rosette growth stage, before thistles are 250mm high or across |
| Pack Size |
2.0 litres |
| Dose Rate |
4.0 litres/ha |
| Water volume |
300-400 l/ha |
The weeds must be actively growing.
Leave 2-3 weeks after cutting/grazing to allow sufficient regrowth before spraying.
After application allow:
- 7 day grazing interval before returning stock to treated areas
- 28 days before mowing for maximum translocation
| Contents |
200 g/litre clopyralid
200 g/litre triclopyr |
Apply at the rosette growth stage, before thistles are 250mm high or across |
| Pack Size |
3.0 litres |
| Dose Rate |
1.0 litre/ha |
| Water volume |
200-400 l/ha |
The weeds must be actively growing.
Leave 2-3 weeks after cutting/grazing to allow sufficient regrowth before spraying.
After application allow:
- 7 day grazing interval before returning stock to treated areas
- 28 days before mowing for maximum translocation
To spot treat nettles use Grazon 90. Apply at the rosette growth stage, before the thistles are 200mm high or across.
| Contents |
240 g/litre triclopyr
60 g/litre clopyralid |
Apply when nettles are actively growing, preferably before flowering |
| Pack Size |
1.0 litre |
| Dose Rate |
60ml / 10 litres of water |
The weeds must be actively growing.
Keep livestock out of treated areas for at least 7 days and until foliage of any poisonous weeds, such as Ragwort, has died and become unpalatable.
Fields should not be cut or grazed for 28 days following application to allow Grazon 90 to fully translocate into the root system for long term control.
Grazon 90 is rainfast in 2 hours.
