Plans to restrict the use of IPU to soils where it was less likely to be leached into surface waters were debated by the Advisory Committee on Pesticides, prior to its advice to revoke the herbicide’s approval.

Details of the ACP’s advice, published on the Pesticides Safety Directorate’s website, make it clear the committee decided management practices to limit its impact on aquatic organisms would not work.

Restricting its use to soils less vulnerable to IPU loss via drains, thus reducing the possible concentrations reaching surface waters, would result in the continued availability of IPU only in areas where it would be of limited use in weed control, it said.

The committee also suggested considerable development work would be required to enforce such a scheme. “One possible route might be to consider amendment to crop and soil protection plans under cross-compliance and entry level stewardship, but further research would be necessary.”

Problems

Financing such research would likely have been a problem, admits Patrick Stephenson, a North Yorkshire AICC agronomist. “Even the IPU manufacturers don’t consider IPU to be a cash cow, so it would be hard to see who would pay for the work to support a much reduced area for sales.”

But he disagrees with the ACP assessment that IPU would be of limited use for weed control in the less vulnerable areas. “I’m assuming it means areas of clay soils where it is less likely to leach. There’s a lot of wheat grown on those soils.”

The ACP was also concerned the re-registration process was product- rather than scenario-based. “The committee was concerned growers were likely to select alternative products, some of which were also due to be considered for re-registration and are suspected to have similar environmental profiles. The committee considered whether under these circumstances scenarios should be considered so the balance of risks between alternatives could be considered.”