PESTICIDES’ IMPACT UNDER REVIEW

Could you prove before buying a pesticide that you have measures in place to compensate for the indirect environmental effects it may have?

That’s one possible nightmare scenario for farmers, suggested at last week”s Advisory Committee on Pesticides open meeting in York.

The good news is that any move to incorporate indirect pesticide effects into environmental risk assessments is unlikely for a couple of years at least. Indeed, no decision has been taken on what the appropriate action should be, or if there should be any.

“Farmers shouldn’t be quaking in their boots,” stressed ACP chairman David Coggon.

Current pesticide regulation focuses only on direct effects, such as survival or reproduction of non-target animals, says Robert Smith, deputy chairman of the Advisory Committee on Pesticides.

But last year’s genetically modified crop evaluation trials had a much broader remit, also considering indirect effects, such as the loss of chick food for some farmland birds.

That’s opened up the possibility of all pesticides being assessed for their risk to wildlife in a wider sense, which could require compensation for any adverse effects.

“The difference may lead to some conflict with pesticide and GM crop approval committees working to different rules,” adds Prof Smith.

That could be a problem if, for example, a herbicide was registered for use on both GM and non-GM crops, says Alastair Burn, chairman of the ACP sub-group considering pesticides” impact on wider biodiversity.

“Indirect effects are more important for farmland biodiversity but we are less adept at managing them.”

Dr Burn’s working group’s proposed risk assessment scheme to measure a pesticide’s indirect impact appears to bring extra regulation one step closer.

The proposed target is to protect biodiversity action plan species, and other significant species, which are rare or in decline, as well as managing the availability of plants or insects that act as food sources for those two groups, he says.

Food Availability

 Assessing how spraying an insecticide might influence populations of target species is directly linked to the availability of insects for chicks to feed on. Research suggests about 35% of grey partridge chicks need to survive for populations to remain stable, when using weedkillers, but no predation control on farm. “Food availability for chicks acts as a good indicator for insecticides.”

For herbicides, the indicator is seed production by in-field plants, whose seeds are important in the diet of bird species.

So what if a pesticide exceeds a yet to be decided trigger level for indirect environmental effects?

“That would result in growers managing the effects either in-field, or adopting compensating measures not directed at the pesticide per se,” says Dr Burn. For example, growers could use lower rates, patch spray, choose alternative more selective products or compensate by leaving undrilled patches, beetle banks or larger areas of set-aside.

Implementation might be through either regulation or, either wholly or partly, through incentives, such as agri-environment schemes, or promotion of best practice, he suggests.

One method could be to link it to chemical distribution, suggests Gareth Edward-Jones, professor of agriculture at Bangor University. “Depending on which field it is applied to, growers might need to prove compensation measure A, B or C is in place before buying the chemical. But it is a very complicated approach.”