Over the next couple of weeks, weeds in pasture are set to flourish. Docks, Thistles and Nettles are often the main contenders to deal with. Now is an ideal time to spray these weeds while growth rates and temperatures are high and while these weeds are at the correct stage of growth.
As a general rule of thumb, a 1% weed infestation results in a 1% grass yield loss. Highlighting this further, a 10% weed infestation in a sward, capable of growing 13.0 tonnes of dry matter per hectare (DM/ha), equates to a 1.3 tonne total yield loss or a whopping 1.0 tonne loss of utilised grass per hectare (80% utilisation)! NB: If this 1.0 tonne must be replaced with purchased concentrates, there is quite a substantial cost incurred versus the cost of controlling the weeds. Typically, a 10:1 return on investment can be expected from a successful weed control application; one of the best returns on investment (ROI) you will get on a farm.!!
When Should Herbicides Be Applied
The key to successful spraying is to get as much of the active ingredients, taken up by the plant as possible. This requires large, healthy, actively growing leaves on the plant. As the plant reaches the point where it starts to go to seed, leaves have finished growing and will no longer effectively take up the chemical. In such cases the field should be topped and spraying delayed for 2-3 weeks.
Ideally spray on a calm dry day with no rain in the immediate forecast. Spraying on a dry leaf is best.
IPM approaches to grassland weed control
- Avoid extreme poaching of paddocks - weeds are
opportunistic and require open soil and daylight to germinate. - Carry out drainage work where necessary. Creeping Buttercup thrives particularly well in poorly drained soil.
- Do NOT allow weeds to go to seed (Topping). Docks can produce over 60,000 seeds per mature plant.
- Rotate silage ground to help avoid silage swards
becoming overly open. - Correct soil fertility – this ensures a more competitive sward, allowing weeds less of a chance. Weeds like
Dandelions will often thrive on poor fertility sites. - Employ a good reseeding policy using a post emergence spray at the correct timing.
Herbicide Options This Season
PasturePack :
A broad spectrum control option for use in established leys.
Has the combined benefit of three active ingredients for excellent control of docks, nettles and thistles.
For persistent control of strong weeds, use one pack to treat 2 ha (5 acres).
For routine shorter term control, use 1 pack to treat 3 ha (7.5 acres).
Reaper/Hurler:
A good value spray for control of docks and chickweed.
Doxstar Pro:
Offers excellent dock and chickweed control
.
Forefront T:
Choose for long-term control of a broad range of weeds.
(Not for use in silage ground)
Grazon Pro:
Ideal for knapsack treatment of docks, nettles and thistles.
Pastor Trio:
Provides an excellent spectrum of weed control in BOTH permanent pasture and reseeds and is suitable for use in silage swards. Provides effective control of Thistles which may be a problem in some reseeds.
Envy:
An extremely safe option for use where horses or cattle graze. Controls Docks, Chickweed, Buttercups and Dandelions in established and new sown swards.
Contact your local Drummonds branch where staff will advise you on the most suitable herbicide for your grassland weed control.