Vegetable sector must understand weed control options, warns UAP

Vegetable growers in the UK are facing a brave new dawn in terms of their available herbicide armoury for weed control following the ending of 'Essential Use' status for several active ingredients (ais) at the end of last year.

However, with the European Commission's Review of Pesticides still ongoing, one expert warns that restrictions, or complete removal of products seen so far, could just be the tip of the iceberg.

"The 'Essential Use' products have gone - growers know this and hopefully they used up what they had in store before the end of last year," says UAP technical adviser, Chris Wallwork. "However, over the next two years a number of other herbicides will disappear completely or be restricted by factors such as lower dose rates, less applications and longer harvest intervals. Some of these we already know about but, worryingly, there will be many that we don't."

Mr Wallwork believes that the rate at which products are reviewed is likely to accelerate during the next few years. He comments: "The European Commission's Review of Pesticides is only halfway through, despite it being originally scheduled to be completed at the end of 2008. Not only is it taking time to process new active ingredients being put through registration but re-assessment of existing products to the same standards as new ones is a slow process.

"What growers may not realise is that products which do get through the registration process and on to the Annex 1 Listing will be subject to restrictions in individual Member States. What may have been an acceptable dose rate and timing pre-registration may not be appropriate afterwards. Annex 1 Listing guarantees that an active ingredient can be sold in the European Union, but does not that a grower can use it as he used to."

Despite diminishing weed control options for vegetable growers in the coming seasons, Mr Wallwork stresses that it's not all doom and gloom, adding: "The important thing is that the Horticultural Development Council (HDC) has identified suitable materials either already in use with other crops in the UK or those that are completely new. These will help fill some of the gaps left by products which have been removed."

Part of the problem though, says Chris Wallwork, is learning how to 'drive' new products for use in vegetable crops, which can require a big investment in time.
Offering specialist agronomic advice to the vegetable sector, UAP learns about new herbicide developments through formal trials work of its own, through the HDC and agrochemical manufacturers' trials and by on-farm comparisons with grower customers. Mr Wallwork believes that grower trials, with UAP's guidance, are an important part of getting the feel for the impact that a herbicide makes.
He concludes:

"The vegetable sector needs to learn how to live without the old products but at the same time to find out about the new ones. It needs to know how to have effective weed control without harming the crop. In the future, what growers and advisers have learned together over the last 20 years about managing weeds in their crops will have to be compacted into two years."