Scientists are saying efforts are failing to control an invasive insect thatis slowly killing off beech trees in Nova Scotia.

The insects are European natives called beech leaf mining weevils. Adult weevils lay their eggs in young leaves and produce larvae that eat through the foliage.

Weevils have left thousands of beech trees in Halifax without leaves. 

“It is wiping out a certain amount of the native beech stove,” says Halifax urban forester, John Simmons.

Damaged beech trees started showing up a decade ago, but it took years for scientists to identify the culprit. Some European beech trees have developed defences against the insect, but Simmons says Nova Scotia’s beech trees don’t stand a chance.

“We've seen decline in areas, and total removal of stock of beech trees, native beech trees, in certain park areas,” he says.

The first weevils were detected in Halifax about five years ago and have spread to other areas, including Sydney.

Edith Angelopoulos taught biology at Dalhousie University for 30 years and specialized in insects. She says weevils may be invasive,but people are part of the problem.

“Of course where they cause damage,because the little maggots that grow up in there feed on the tree,” she says.

Angelopoulos says free trade is spreading the invasive insects with the use of chemicals.         

“When you consider how many millions of years the world has been expanding and developing and evolving, and there has never been the problems that we have today,” Angelopoulos says.

CTVNews contacted scientist Jon Sweeney of the Department of Natural Resources at his office in Fredericton on Wednesday. Sweeney acknowledged that the infestation is spreading.

He says the Canadian Forestry Service is experimenting with botanically derived insecticides and although their results are promising, theyarestill waiting for approval to use it on a larger scale.

Like Angelopoulos, he believes biological control would be the best strategy to fight the pests,but he says researchers need to identify the right parasite to kill the weevils without causing another set of problems.

With files from CTV Atlantic’s Bruce Frisko.