A European move to outlaw a controversial class of pesticides has been lauded by environment groups - but a similar ban here could cause headaches for agriculture, experts say.
Over the weekend, the European Commission voted to ban neonicotinoid pesticides in EU member states at the end of this year, with only closed greenhouses exempt.
The move followed concerns and new evidence that neonicotinoids could affect some pollinators, including honeybees, whose population declines had been linked to the agent.
Used extensively to protect crops here and overseas, many neonicotinoids have systemic effects on plants, meaning treating the seeds with them can leave a plant protected throughout its life.
They have largely replaced problematic insecticides used in the past, such as organophosphates and DDT, although in light of environmental concerns, major retailers including Placemakers, The Warehouse and Bunnings Warehouse have taken them off the shelves.
Current New Zealand rules around neonicotinoids include not spraying insecticides close to bee hives or crops with budding or flowering plants where bees may gather and feed.
The Environmental Protection Authority (EPA) said while rules here were working, there could still be instances where non-target organisms, like bees and insects were exposed.
"When new information is released, the EPA always takes a good look at the science, evaluating it to see if there's something we need to factor into our thinking here," said the EPA's general manager for hazardous substances and new organisms, Dr Fiona Thomson-Carter.
The EPA worked closely with the OECD-initiated Pollinator Incidents Information System, through the EPA's Pollinator Strategy.
"This system is building a global picture of bee health and incidents, so we can compare what's happening in New Zealand with other countries bearing in mind that agricultural practices in New Zealand are not the same as in the EU."
But New Zealand's Soil and Health Association wanted to see the EPA follow the EU immediately.
"By deeming neonicotinoids safe and allowing for their continued widespread sale and use in New Zealand, we believe the EPA is failing in their statutory obligation to recognise and provide for the life-supporting capacity of air, water, soil and ecosystems," said the association's chair, Graham Clarke.
AgResearch scientist Mark McNeill said the challenge here was that neonicotinoids remained an effective way to control damaging seedling pests such as the Argentine stem weevil, black beetle, springtails, caterpillars and slugs.
"Protection during the seedling stage is critical to the production and persistence of these pastures and crops."
McNeil said neonicotinoids were also less toxic to humans than organophosphate insecticides, and were considered a more environmentally friendly means of crop protection compared to broad-spectrum foliar sprays.
This was because they were highly targeted and therefore didn't have the same risks of environmental exposure and impact as aerially-sprayed agents would.
Further, they allowed crops and pastures to be established by direct drilling - where the seed was drilled into unploughed soil - thereby reducing nutrient leaching and carbon emissions.
"While it is early days yet, the withdrawal of neonicotinoids will cause some issues for farmers, as there are no ready alternatives," he said.
"Irrespective of any future decisions, New Zealand farmers need to have effective and safe treatments for controlling pests at the seedling stage."
University of Otago geneticist Professor Peter Dearden said there was no indications that New Zealand's honeybee populations had suffered the same decline as bees in Europe, although there were no good long-term monitoring projects of other insects here.
Like McNeil, he pointed out neonicotinoids were far safer insecticides than those used previously, and that the country had very few alternatives if they were banned.
Neonicotinoids were also the key ingredients in Vespex, an important way of controlling invasive wasps in New Zealand and important tools in controlling pasture devouring weevils.
"What is really needed in New Zealand is an understanding of the impacts of our use of insecticides on both agricultural and natural environments, as well as monitoring of residues from insecticides in groundwater and soil," Dearden said.
"With this data, we could make informed decisions on the costs and benefits of insecticides."
While there were some existing alternatives to insecticides, ceasing their use would "completely would raise challenges" for agricultural productivity.
"The neonicotinoid story, as well as that of organophosphates and DDT, may indicate that our approach to insects generally is wrong," Dearden said.
"Insects are key parts of our ecosystems and critical to our continued existence on the planet.
"Perhaps we should be cherishing them, finding ways to avoid agricultural damage without killing them, and ensuring they are not needlessly killed, as a better way to ensure sustainable agriculture."