Toxins in the environment could be causing honeybee populations to dwindle in New Brunswick, Ontario and the northeastern states, an American researcher says.

Beekeepers in the New Brunswick region are reporting an 80 per cent decline in hive population. Insects have been leaving their hives and not returning.

The cause of the problem is still unknown, but researchers at the University of Illinois think they may be on track to linking the bee losses with increased pesticide use.

May Berenbaum, head of the entomology department at the university, said chemicals may be causing bees to forget the way home.

"There are some neurotoxic insecticides that can interfere with honeybee memory, and that might be manifested in disruption of their orientation and navigation abilities," Berenbaum said.

It's too soon to say exactly which pesticide may be causing the problem, but there is evidence that points to new synthetic pesticides called neonicotinoids, Berenbaum said. Studies in France have already shown some link between the products and a declining bee population, she said.

"The neonicotinoids are newly designed synthetic chemicals that act essentially against the nervous system," Berenbaum said. "They're relatively new and they have been shown in lab studies to impact honeybee behaviour."

More tests need to be done and the honeybee problems may end up being traced to dozens of pesticides in the air, Berenbaum said.