Pesticides linked to a global decline in bee populations also threaten other pollinating insects and represent a risk to many varieties of wildlife, scientists say.

An analysis of all available research -- more than 800 studies -- suggests systemic pesticides such as neonicotinoids and neonics are causing substantial damage to a great number of beneficial species and have had an especially significant impact on bees, they say.

A group of independent scientists from around the world working as the Task Force on Systemic Pesticides have published their findings in the Journal of Environment Science and Pollution Research.

"The evidence is very clear. We are witnessing a threat to the productivity of our natural and farmed environment equivalent to that posed by organophosphates or DDT," study co-author Jean-Marc Bonmatin of The National Center for Scientific Research in France said.

"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 class of pesticides that was analyzed work by interfering with the nervous systems of agricultural pests and are widely used in crop farming, horticulture, forestry and even as household pest control agents.

The current system for regulating the use of such pesticides has failed to consider the full range of their effects on species as varied as bees, aquatic invertebrates and even birds, the researchers say.

Large-scale use of the pesticides has resulted in widespread contamination of the environment, as they work their way into soils in wetlands and coastal regions, they say in their published "worldwide integrated assessment."

There's little publicly available information in most countries on how much those pesticides are being used and where they are mostly being applied, they said.

There is fear of the dangerous effects of the pesticides moving up the food chain, says assessment co-author David Gibbons, chief scientist at the Center for Conservation Science at Britain's Royal Society for the Protection of Birds.

 ''Although the effects on birds and other vertebrates remain unclear, the analysis suggests they are at risk, both from the direct toxicity of these chemicals and by depleting the numbers of other insects on which they depend for food," he said.

''For the sake of nature, farming has to find ways of producing food without putting the environment and its own future under unsustainable stress.''