Simplifying weed control in newly sown leys with clover

Agriland

09-06-2025

Controlling weeds in newly sown leys containing clover has become easier thanks to ProClova XL, the herbicide manufactured by Corteva Agriscience.
ProClova XL's two active ingredients – Rinskor and amidosulfuron – provide the widest spectrum of weed control in newly sown leys.
When pastures are being reseeded, it is critical that they are promptly sprayed with a post-emergence spray following reseeding to eliminate weeds, allowing both the grass and clover to establish.
Chris Maughan, technical manager with Whelehan Crop Protection, distributors of ProClova XL in Ireland, said: 'The ideal timing for ProClova XL is about six to eight weeks after reseeding.'
'The grass should be at the tillering stage with three trifoliate leaves on the clover at the time of application and the weeds should be small and actively growing, and this ensures that they are eliminated out of the sward early and prevents them from smothering out the grass.'
Weed control
According to Maughan: 'ProClova XL controls a wide range of weeds including chickweed, docks, and other annual weeds including fat-hen, red dead nettle, redshank, and fumitory.
'Chickweed, if not controlled, can totally smother out the grass. If these fields are not sprayed, the chickweed will continue to flourish, killing out the grass seedlings which then allows other weeds such as docks, thistles and buttercups to germinate.
'The end result will be a very poor pasture and a wasted investment.'
Maughan also highlighted the damage docks can wreak on a new reseed.
'Killing docks at the seedling stage is vital. This ensures total kill and prevent the docks from establishing a deep taproot,' he said.
Chickweed can be devastating to a new reseed
ProClova XL is the product of choice when addressing chickweed, according to Chris Maughan of Whelehan Crop Protection
The above images illustrate the damage that chickweed can inflict on a reseeded paddock.
The first picture (left) shows an area left unsprayed. The following year, (centre) dead chickweed is visible where it has smothered out the grass with perennial weeds including docks and thistle beginning to germinate within the bare patches. Two years on, (right) one can see the docks are now well-established.
Temperature and timing is everything
It is important to apply ProClova XL during periods of active growth to get the best weed control.
For optimal results, spray when night temperatures are forecast to be above 8℃ for a minimum of three days before and after the planned application date.
Available in a twin pack
ProClova XL is available in a box containing two bottles – ProClova and XL.
The ProClova bottle contains the herbicides, Rinskor and amidosulfuron, while the XL bottle contains an adjuvant oil that improves the reliability of weed control while providing maximum safety to both the grass and clover.
The area to the right was sprayed with ProClova XL in April 2022 before silage was cut. The picture on the left was then taken a few weeks later following a cut of silage.
ProClova XL Factfile
Use from April to October in new leys
Rate In newly sown leys: 85grms + 165mls/ha (one pack treats 3ha)
In established grass or where ground cover is greater than 90%, use the higher rate 125grms + 250mls/ha (one pack to 2ha)
Controls key weeds including docks, chickweed, fat-hen, redshanks, and red dead nettle
In established grassland, it also controls dandelions, buttercups, plantains, cow parsley, and hogweeds.
Rainfast in 1 hour. Livestock should be kept off for seven days post-treatment (in the absence of ragwort).
Use from the tillering stage of the grass and when the clover has three trifoliate leaves present.
Clover safety: A transitory effect (leaf deformation/growth inhibition) may be seen following application, but full recovery will follow after two/three grazings.
Red clover: When used on grass leys containing red clover, ProClova XL should be applied in the year after establishment – so reseeds sown last autumn containing red clover can be sprayed this spring.
Established grassland: ProClova XL can also be used on established grassland where clover preservation is key. it provides the highest level of dock control available in clover swards. It is also effective on other weeds like dandelions, buttercups, plantains, hogweeds and cow parsley.
For optimum control, spray actively growing weeds at the correct growth stage, 8-10cm across and at the rosette stage. If weeds have grown beyond the correct growth stage, top them and spray regrowth with ProClova XL.
Best practice advice
Apply ProClova XL with at least 75% drift reducing nozzles.
Do not apply ProClova XL to fields where an intersecting watercourse is present (i.e., where the land parcel slopes towards a watercourse and any surface water run-off would drain into that watercourse).
When spraying fields, respect an unsprayed buffer zone to watercourses of 3m.