Oregon agency blames pesticide for thousands of bumble bee deaths WILSONVILLE, Ore. - Oregon officials say a pesticide is to blame for the deaths of tens of thousands of bumble bees in a shopping center parking lot southwest of Portland. The state Department of Agriculture said Friday that tests on bees and foliage showed the deaths are "directly related to a pesticide application on linden trees" that was meant to control aphids. It said an investigation is under way to see if the application of the pesticide Safari, done last Saturday, violated the law. The Oregonian reports that the Agriculture Department, the City of Wilsonville, neighboring towns and some local landscape contractors have covered the sprayed trees with netting in an effort to prevent further insect deaths. The Xerces (ZERK'-zees) Society for Invertebrate Conservation has upped its estimate of the bee kill to 50,000. Spokesman Scott Black calls that a very conservative number.