United Agri Products (UAP) technical adviser Chris Wallwork explained that "what growers and advisers have learned over the past 20 years about managing weeds will (now) have to be compacted into two (years)".
He went on to warn of a "brave new dawn" for herbicides. This followed the end of essential-use status for several ingredients last year and the EC's ongoing review of pesticides, set to overhaul restrictions or remove products.
Wallwork said: "Over the next two years, several herbicides will disappear completely or be restricted by factors such as lower dose rates, fewer applications and longer harvest intervals.
"Some of these we know about but, worryingly, there will be many we don't. The rate at which products are reviewed is likely to accelerate during the next few years."
He warned that the EC's delayed review was only half-way through, while the reassessment of existing products was a slow process.
"Growers may not realise that the products that do get through the registration process and on to the Annex 1 listing will then be subject to restrictions in individual member states."
This means that what was once an acceptable dose rate and timing may no longer apply.
Annex 1 listing guaranteed that an active ingredient could be sold in the EU, but did not state a grower could use it as they used to, Wallwork explained.
However, the HDC had identified suitable materials or new ones, he added. "These will help fill some of the gaps left by products that have been removed."