Oregon Department of Forestry will check coastal forests for signs of spruce aphid damage after outbreak found near Yachats

SALEM, Ore. – Earlier this year a spruce aphid outbreak was detected around Yachats on the central Oregon coast. ODF will be assessing the spread of this damage to determine where else it might be occurring along the coast.

Spruce aphid is a long-established exotic and invasive insect that experiences periodic outbreaks that injure Sitka spruce along the West Coast, including Oregon. Spruce aphid (Elatobium abietinum) sucks moisture and nutrients from older needles on Sitka spruce trees, causing them to turn yellow, red, and then drop. The aphids don’t feed on new needles. This insect actively feeds in February and March. By early summer when   needle drop begins to be seen it is too late to do anything about outbreaks, as populations of this insect have already declined.

Although trees are injured, they don’t often die from this damage because this insect is only periodic, does not feed on current year needles, and does not kill buds. However, trees that have other underlying stress issues will be more heavily impacted. Sitka spruce is often stressed by flooding and brackish water if growing too close to the coastline, therefore those trees might be more at risk from the additional impact of spruce aphid.

“We don’t typically see back-to-back outbreaks in the same areas, but because outbreaks often occur after a particularly warmer than usual winter or when we don’t get a late cold snap – and these are becoming more common with climate change – it is possible that we will eventually see more outbreaks one after the other,” said ODF Forest Entomologist Christine Buhl.

Able to tolerate salt spray, Sitka spruce grows in moist coastal forests seldom more than a few miles inland from the Pacific Ocean. Typically growing between 125 and 180 feet tall, they are long-lived trees capable of living several centuries. Many of the largest old-growth Sitka spruce were cut down to build airplanes in the early 20^th Century or to make violins, guitars, and pianos.

More info: https://www.oregon.gov/odf/documents/forestbenefits/Spruce_aphid_2017.pdf

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