What kind of moth is it?

Asked October 5, 2015, 1:51 PM EDT

Moth - wings at rest are held to the sides parallel to surface resting on Body & wing span (at rest) smaller than the head of a standard straight pin... about the side of a printed 10pt asterisk * Pure White Millions of them... literally ...often in dense clouds Washington, Yamhill, Multomah, Clackamas Counties Found in every environment from garden, to yard, to hiking trails, to parking lot, to highway Never saw them before here in Oregon... but this year, for the last month, they have been extensive - and very annoying when you have to walk through a cloud of them! What are they? What do the larvae look like? What do they eat? Do I need to be concerned for my clothes, garden, yard... what?

Washington County Oregon

2 Responses

Judging from your description of millions of tiny white flying insects, it’s likely you are seeing ash whiteflies, Siphoninus phillyreae, which were first identified in Oregon during 2014. Many people in our nearby counties have noticed clouds of the same speck-sized flying insects during the past several weeks. Judging from the number of calls and emails we’ve been receiving from the public, it’s obvious the whiteflies have expanded their territory this year. These whiteflies have been potentially serious pests of ash trees and certain other woody plants elsewhere but, in those areas, are now under good control from introduced natural enemies.

Very little is known at this time about how damaging ash whitefly might be in Oregon or what sort of management may be needed. Treatment, if needed, should only be applied if infested leaves are found because the susceptible targets are the small oval youngsters.

This webpage (late 2015) for commercial growers has some background information and images of infested leaves: http://oregonstate.edu/dept/nurspest/Ash_whitefly.html.

Also see this recent news report: http://oregonstate.edu/dept/nurspest/Ash_whitefly.html