ASPEN, Colo. -- An Aspen beekeeper has released 140,000 ladybugs to attack an aphid infestation plaguing the city's cottonwood trees.

Ginger Janssen released the bugs Thursday and plans to release 280,000 more in the next two weeks. She said she paid about $150 for them.

Janssen said ladybugs are an environmentally friendly alternative to insecticides that city officials are using.

"They focus on one insect and don't think about the rest of the ecosystem," she told the Aspen Daily News. "We want people to know there's an alternative out there that's a lot better for everything."

She believes insecticides are responsible for a collapse of bee colonies around the world. She worried her bees will be affected because they use cottonwood sap to seal their hives.

City Forester Chris Forman liked the idea of ladybugs but wasn't sure they alone can get the job done.

Earthwise Horticulture, the company hired by the city to administer the insecticides, said using them responsibly minimizes the impact on other organisms.

"They'll only add to the natural population. I don't know how well they'll do, I can't say if it'll work, but it can't hurt," said Forester of Aspen Chris Forman.