EDMONTON - There's some promising news in the ongoing fight against the spread of the destructive mountain pine beetle in Alberta's forests.

The latest survey shows a large number of the bugs didn't survive the winter in the northwest and Slave Lake areas, which will curtail their spread eastward this summer.

But Alberta Environment warns the war against the tiny insects, which have killed or infested more than one million pine trees, is far from over.

There are still large numbers north of Peace River and near the west-central communities of Edson and Whitecourt.

Experts say a large number of the bugs died over the winter because of fluctuating temperatures that make them susceptible to sudden cold snaps.

Alberta has spent $296 million fighting the beetles since 2005, including $40 million for efforts this year.