Seattle enlists wasps in battle against marauding moths

THE ASSOCIATED PRESS

Originally published July 5, 2001

SEATTLE -- It's the battle of the bugs.

Instead of using pesticides, the Seattle Parks Department is recruiting parasitic wasps to attack moths that have been making their way south from British Columbia, destroying cherry trees as they go.

The pests -- known as cherry bark tortrix moths -- began wreaking havoc on cherry trees at Peace Arch Park at the border several years ago.

Since then, they've been heading south. In a two-week span recently, 29 were caught in a trap at Leschi Park on Lake Washington.

But the Parks Department has a new secret weapon: wasps smaller than a fruit fly that lay eggs in the moths' larvae, killing them. The wasps won't sting people or pets, and the city is releasing 200,000 of them at 22 sites around the city.

The moths kill trees by laying their eggs in the bark. The hatched larvae eat their way into the circulatory system of the tree, eventually blocking nutrient movement.

"It's like putting a tourniquet around your arm," said Lynell Tanigoshi, a research entomologist at Washington State University of Vancouver.

The larvae can also damage the tree by creating habitats for bark beetles and fungi. The trees become susceptible to disease and damage from freezing temperatures.

The Olympian Copyright 2001

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