Lessons of Edmonton infestation brought north
Richard Gleeson
Northern News Services
Yellowknife (May 30/01) - If the public and science supports it, the city will introduce a new species of insect to the North this fall.
Lathrolestes luteolator is a mosquito-sized wasp that was used in Edmonton to eliminate infestations of birch leaf minor, a pest that is damaging trees in Yellowknife and Hay River.
The wasp lays its eggs on birch leaf minor larvae. The larvae becomes the wasp's first meal once it hatches.
The birch leaf miner causes leaves of birch trees to turn brown. It is not a fatal infestation.
City facilities manager Tony Burge said if the public is agreeable and the information provided by experts supports the introduction of the wasps, the city will bring them up in the fall.
When they hatch next spring, the wasps will begin their work.
The Edmonton experience indicates the only alternative to the wasp is an ongoing pesticide use.
"I feel that what we went through here in Edmonton -- 15-20 years of chemical treatment -- I'd like to see if we can help other places avoid that if at all possible," said Chris Saunders, a biological sciences technician who helped Edmonton deal with its infestation.
Last summer a Yellowknife child had to be hospitalized after coming into contact with a pesticide used to control the birch leaf miner.
Saunders will be giving a public presentation on Edmonton's experience with the birch leaf miner and the wasps Thursday at Northern United Place starting at 6:30 p.m.
Saunders said the wasps, which migrated to Alberta from eastern Canada, were a "wonderful success" in Edmonton. They eliminated the problem within a few years of their arrival. He estimated that 500 wasps would need to be introduced to control infestations here.
The wasp preys only on one of the three species of birch leaf miner, reducing the risk of upsetting the balance of nature here. The birch leaf miner was likely inadvertently imported to the city on the leaves of trees shipped up from Edmonton nurseries.
"That particular control agent (the wasps) might already be here," said Bob Decker, a territorial forest ecologist working out of Hay River.
Decker said analysis of leaf samples taken in Hay River last summer showed 17 per cent of the leaf miner larvae had wasp eggs on them.
Analysis of 70 leaves taken from Yellowknife trees was not nearly as encouraging. All the larvae were alive and well.
In Hay River this summer biologists will determine whether the wasp has arrived and whether any other species of birch leaf miner are present there.
Decker and other Resources, Wildlife and Economic Development staff will trap insects using Post-it sized cards with adhesive on both sides.
