Potential pesticide product removals through the Water Framework Directive could cost UK cereal and oilseed rape growers over £500m a year – and that’s just from losses due to blackgrass, a new ADAS report suggests.

While the Environment Agency has stressed it wants to use voluntary approaches where possible to overcome issues with certain pesticides in water, there remains the possibility that if all other measures fail, severe restrictions or bans might be put in place.

It is this eventuality the ADAS team, led by James Clarke, have investigated for the HGCA, along with the impact of the new EU pesticides approval legislation agreed earlier this year.

The key findings in the review are that pesticide product losses because of the Water Framework Directive would have a much greater financial impact on UK growers than losing the pesticides under threat from the new approvals regulations, and that weed control would be hit hardest.

Actives that were either used at high rates or on large areas were most at risk of breaching the directive’s ecological or chemical water standards, Mr Clarke explained at a HGCA briefing last week.

Potential legislation costs to UK growers 

  Pesticides Approval revision Water Framework Directive
 Blackgrass  £185m  £529m
 Ryegrass  £22.4m  £204m
 Septoria tritici  £16.2m  £57.3m
 Slugs   £0m  £49.3m
That captured several key herbicides, particularly residuals, which tended to be applied in relatively large doses directly to the soil and worked most effectively in moist conditions, he pointed out.

The loss of key oilseed rape herbicides – metazachlor, propyzamide and carbetamide – would cost growers nearly £90m a year through the loss of blackgrass control, the report estimated.

More blackgrass would come through into wheat crops as a result, Mr Clarke suggested. That, coupled with the loss of glyphosateand the associated difficulties cleaning up seed-beds prior to drilling, and chlorotoluron meant there would need to be more ploughing and later drilling of wheat crops.

In total, ADAS estimated growers would lose more than £350m in wheat through blackgrass.That compared with £150m, mostly because of the loss of pendimethalin, from changes in approvals criteria.

The potential loss of key triazole fungicides under that legislation would, in contrast, have a relatively small impact – costing the industry £16.2m in loss of septoria control.

“The key issue is how endocrine disruption is defined. If we lose one or two triazoles it is not the end of the world. So we may lose the first choice product, but others will be available, and there will only be a small loss in control,” Mr Clarke said.


The review should focus attention on the areas where more research or better knowledge transfer is required to either prevent product losses or to overcome their impact, Mr Clarke suggests in the HGCA report.

“Protecting important active substances and finding ways of ensuring their continued availability should be a priority,” he says.

Among the priorities should be to investigate the routes through which pesticides reach water and their relative importance for different pesticide groups, and developing better predictions of future weed, pest or disease risks.

Weed control research also needed to be a priority, he said at the briefing. “You don’t have to be a rocket scientist to see there are more disease projects currently than in weed science.”

Projects that should be considered included improving prediction of how much weed control was actually needed across the rotation and to identify new opportunities for weed control in oilseed rape.