The recent discovery by shoppers of 50,000 dead bumblebees in a Target parking lot was pure B-movie material, as if the sky had rained death. But the carcasses were especially concentrated beneath some 55 European linden trees recently treated to resist infestations of aphids, which issue the clear sticky liquid droplets that can mar windshields and perhaps a satisfying shopping experience.

Bee carcasses were collected and cut open by Oregon Department of Agriculture investigators. They were found to carry high levels of the popular, unregulated insecticide Safari. Agriculture officials quickly announced that bee-proof netting would wrap the canopies of the trees, at the Wilsonville Target near I-5, to ‘keep additional bees from blooms that have been attracting the pollinators.’

Soon enough, reports surfaced of hundreds of dead bumblebees beneath linden trees in downtown Hillsboro, and state officials quickly responded to take samples. It turns out the Hillsboro trees had been treated with Safari as well, though no link was announced between the chemical and the bee deaths. And the time between application and reported die-off was much greater than it was in Wilsonville.

State agriculture officials told The Oregonian’s editorial board on Tuesday that they expect to take up to two months in […]