However, once established, docks can seriously reduce sward productivity, silage yields and digestibility. Chemical control may be needed, before infestation becomes severe.
Every effort should be made to preserve beneficial plant species present in the sward, such as clover.
In this article we look at various herbicide sprays for controlling docks in grassland swards and their effect on clover.
Dock control in non-clover grasslands
Bandock, Forefront, Doxstar, Pastor, Starane2, Foundation and Kildock will kill established docks.
CMPP products will kill clover (Twinprop, which can be used only up to Jun 30, 2013).
Where clover is of consequence in established grassland
Eagle, Prospect or Asulox may be applied. These products do not harm clover, but Prospect or Asulox may have some effect on the constituent grasses in the sward.
The last day for the sale of Asulox was Dec 31, 2011; Asulox cannot be used after Dec 31, 2012.
These products are best applied in good growth conditions, and will give season-long control.
Eagle has label clearance for dock control on grassland, at the 40-60g/ha rate, 60g/ha being the full recommended rate for docks.
The higher rate should be used where the infestation is high, or the docks have a well-established tap root.
Most grassland weeds are the correct stage for weed control.
* Best control of docks will be achieved in good growing conditions when docks are actively growing (rosette stage), and nutrients are actively being transported to new foliage and roots.
* If seed stalks are seen on the plant, or if the dock has diseased leaves, or is under pest attack, it is better to cut/top, or graze and allow regrowth of the docks before applying chemical.
* Do not apply chemicals in a period of drought, because the chemical will not be taken up by the plant leaves in sufficient quantities.
* Use the highest water rates on the manufacturer’s label for best effects.
* High dock populations may need a follow-up treatment.
* Grass should not be cut within 28 days following application of some sprays.
* Check spray labels for individual recommendations.
There are major changes to the CMPP labels for the current season.
* Straight versions of CMPP-P have been or are currently being re-registered.
Their use on agricultural grassland is being removed.
* Products are being allowed the customary one year use up on farms.
* Newly registered CMPP-P products will not be allowed on agricultural grassland in 2012 and future years.
* When spraying, always remove stock from area being sprayed.
Leave at least one week before reintroducing stock back into the sprayed area.
Follow recommendations on spray labels at all times.
Seedling docks and tillage weeds such as redshank and chickweed can be controlled in newly-established swards by using Legumex DB, Alistell and Underclear/Undersown and Mastercrop Undersown.
This spray will not damage seedling clover after the trifoliate leaf stage; and it will not affect young grass plants.
Alistell and Underclear would be the products of choice if chickweed is present.
* By Anthony O’Connor, Teagasc adviser, Athenry and Tim Hyde, environment specialist, Teagasc