An international review of systemic pesticides known as neonicatinoids and fipronil has confirmed these commonly used pesticides are causing significant damage to a wide range of beneficial invertebrate species, including earthworms, and are a key factor in the decline of bee numbers.
The Task Force on Systemic Pesticides, a group of international independent scientists, has analysed 800 peer-reviewed papers on these pesticides, known collectively as neonics, which is due to be published in the journal Environment Science and Pollution Research.
Their analysis found that neonics posed a serious risk of harm to honey bees and other pollinators, such as butterflies, and to a wide range of other invertebrates, such as earthworms, and vertebrates, including birds.
The study found clear evidence of harm sufficient to trigger regulatory action.
Neonics are a nerve poison and effects of exposure range from instant and lethal to chronic.
Fears about their effects on a variety of beneficial species have been growing for 20 years, but the science has been dismissed by manufacturers and regulators as inconclusive.
While New Zealand sources say they have not had time to read the report's detailed findings, beekeepers contacted by NZFarmer said their initial impressions of the study were that it was ''conclusive and wide-ranging, confirming fears held by beekeepers for years''.
This latest study found even long-term exposure at low (nonlethal) levels could be harmful.
In honey bees, chronic damage could include impaired sense of smell or memory, reduced fecundity, altered feeding behaviour, reduced food intake and foraging, in and increased susceptibility to disease. In earthworms, their tunnelling ability was altered.
''The evidence is very clear,'' one of the report's lead authors, Dr Jean-Marc Bonmatin of the National Centre for Scientific Research in France, said in a statement.
''We are witnessing a threat to the productivity of our natural and farmed environment equivalent to that posed by organophosphates or DDT.
''Far from protecting food production, the use of neonics is threatening the very infrastructure which enables it, imperiling the pollinators, habitat engineers and natural pest controllers at the heart of a functioning ecosystem,'' he said.
The analysis found the most affected groups of species were terrestrial invertebrates, such as earthworms, making them highly vulnerable to neonics associated with agricultural use.
The next most affected group was insect pollinators, such as bees and butterflies, which could be highly vulnerable at low or acute exposures. While vertebrate animals were generally less susceptible, the report said bird populations were at risk from eating crop seeds treated with systemic insecticides and reptile numbers had declined because of depletion of their insect prey.
Neonicotinoids have become the most widely used group of insecticides worldwide, with a market share of about 40 per cent and international sales estimated at $US2.63 billion in 2011.
They are also commonly used in domestic treatments to prevent fleas in cats and dogs and to prevent termites in wood structures.
The report's authors strongly suggest regulatory agencies tighten regulations on neonicatinoids and fipronil and start planning to phase them out or reduce their use internationally.