Asked October 13, 2015, 9:12 PM EDT
Washington County Oregon
Many people in our region have noticed clouds of the same small white flying insects during the past several weeks. They were recently identified as ash whiteflies, Siphoninus phillyreae, potentially serious pests of ash trees and certain other woody plants. These insects were first reported to be in the Willamette Valley during 2014. Very little is known at this time about how damaging ash whitefly will be in our region or what sort of management may be needed.
This webpage for commercial growers has some background information and images of infested leaves: http://oregonstate.edu/dept/nurspest/Ash_whitefly.html. Near the top of the page, notice the link to a local garden show with an interview of a university entomologistIt’s not yet been determined if treatment will be needed during the growing season. No action needs to be taken against the adults you see flying now.