Large Sitka spruce trees growing in the Devil's Lake watershed have been a dominant feature of our region for decades. Recently, the trees look like they are dying as their green needles have suddenly turned brown.
Up and down the North and Central Coasts, spruce trees are turning brown. A tiny green bug, the Spruce Aphid (Elatobium abietinum Wal) is the likely culprit.
According to the US Forest Service, spruce aphids are small (1/16 of an inch), soft-bodied, mostly wingless insects. They are light green when young and turn an olive-green when mature. Winged adults have two pairs of wings, with the front pair being much larger than the hind pair. Like other aphids the spruce aphid has sucking mouth parts which they use to suck the sap from foliage. They feed gregariously and secrete “honeydew” which attracts ants.
The aphids have thrived due to several years of unusually mild winters and drier springs. The lack of hard frosts and wintry weather, have allowed their populations to explode.
Lincoln County’s spruce trees look terrible now, but there is hope for them. Spruce aphids typically feast on the sap from older needles causing them to turn brown and drop prematurely. Aphids leave the new growth that appears in May and June alone.
The trees should recover since the aphids have reached the end of their active stage, and have been sucking exclusively on last year’s growth. This is the time of the year that the trees put on their new growth, so look for a greener future.
Experts recommend that you delay plans to remove damaged trees for at least a full growing season. You just might save a bundle and be enjoying a healthy green tree. Not a bad reward for a little patience.