There is a new clover-safe spray on the Irish and UK markets this year called ProClova XL.

The herbicide is licensed for use as a weed killer in established grassland and newly sown leys and is not harmful to clover.

For the past three years, availability of a clover-safe spray was a major challenge as the previously available main active ingredient in clover-safe sprays, 2.4-DB, went out of registration.

A derogation for use was granted but there were supply issues.

Corteva is the company behind ProClovaXL and the spray will be distributed in Ireland by Whelehan Crop Protection. The new spray was 10 years in the making and contains the new active ingredient Rinskor or florpyrauxifen-benzyl. According to Corteva, Rinskor active has a reduced environmental impact because it breaks down rapidly in soil, water and in the tissue of tolerant plants, such as grass and clover.

Rinskor active has a low dose rate compared to many other herbicides. ProClova XL is marketed as a co-pack, containing 250g ProClova and 500ml XL adjuvant, which treats 3ha when you are applying it to newly sown leys or 2ha when spraying established grassland.

Problem-solver for farmers

Chris Maughan, technical manager with Whelehan Crop Protection, says ProClova is a problem-solver for farmers.

“ProClova XL offers two distinct advantages – it tackles a broad weed spectrum without taking out the clover and it can be used on newly-sown leys. Currently, few available herbicides are clover-safe, leaving farmers jeopardising productivity or treating weeds and having the expense of stitching in clover afterwards.

ProClova XL is distributed by Whelehan Crop Protection.

“Clover is playing an increasingly vital role in grass-based systems – helping farmers to minimise use of artificial fertiliser and, in turn, working to develop a more environmentally sustainable farming system, which is becoming increasingly important for the agri-food sector,” he says.

In terms of weed control, the new spray is said to deliver good control on chickweed, fat-hen, redshank and seedling docks in new reseeds while it controls established docks in established grassland.

Corteva says it is 10% better at controlling docks in established grassland than the current standard. It has no control of spear or creeping thistle in either new reseeds or established grassland.

ProClova XL can be used in red clover swards but not until the spring following the establishment of the red clover. So, if red clover is being sown this spring or summer, it should not be sprayed with ProClova XL until spring or summer 2025.


In terms of timing, the best time to spray with ProClova XL is when weeds are at the seedling stage and grass and clover are at the three-leaf stage.

The best time to spray is between March and October and when night temperatures are above 80C for three days before and three days after spraying. The spray is rainfast after one hour.

Animals shouldn’t be left to graze the field for seven days after spraying.

Some “checking” of clover is likely to be observed in the days after spraying such as leaf deformation and poor growth but Corteva says this is normal and full recovery will follow. However, as with all selective herbicides, the plants should not be stressed prior to spraying and spraying should only take place in good growing conditions.

The Irish Farmers Journal understands that Nufarm, which manufactures the Clovermax post-emergence spray, is going to get the product re-registered for use, although this process may take a number of years.