A concerned homeowner in 2010 called to report significant mortality of pine trees in the small residential community of Underwood, Washington, located on the northern bank of the Columbia River Gorge. Consultation with Jenny Cena from Washington State Department of Agriculture, and Glenn Kohler of Washington DNR confirmed the first record of the California five-spined Ips beetle (CFI). After this initial detection, several agencies (USDA Forest Service-Forest Health, Washington Department of Natural Resources, Oregon Department of Forestry, and Washington State University Extension) pooled resources to start measuring the current range of the beetle.
CFI is a native bark beetle known to occur in California, Nevada and the western valleys of Oregon. Until now, the most northern known distribution was the Willamette Valley in Oregon. In 2010, approximately 100 acres with killed and top-killed ponderosa pine were recorded in Skamania and Klickitat counties near the town of White Salmon. Small outbreaks still continue in the area, causing significant tree mortality in Catherine’s Creek Trail area of the Columbia River Gorge National Scenic Area and the small community of Mosier, Oregon, just across the river.
CFI can infest numerous species of pines and has been a serious pest of young ponderosa pine in Oregon’s Willamette Valley since it was first reported there in 1999. CFI can rapidly increase its population in small diameter (but greater than 3 inches) dead pine slash created by storms, fires, logging, or thinning. Offspring can then successfully attack nearby live trees. The risk of outbreak is much higher during drought conditions when live trees are stressed. Outbreaks of CFI typically subside within a year. As with other pine engravers, the likelihood of outbreaks is reduced by assuring that breeding material has time to dry out or is removed before beetles fly in spring.
Thanks to a handful of volunteers and pooled resources, DNR has led a trapping program since 2010 to determine the range of CFI. Thus far, CFI has been found in trapping sites in Clark County, east to Klickitat and north to Thurston counties. It is unclear if this is an expansion of its range or if CFI is reclaiming a historic natural range as west slope pines are reintroduced to the Westside valleys. Continued survey is planned for 2013.
For more information, we have developed the free, WSU Extension Factsheet 085E, Pest Watch: California Fivespined Ips–A New Pine Engraver in Washington State.
Todd Murray WSU Extension Skamania County
Glenn Kohler DNR Entomologist
Beth Willhite USDA Forest Service – Forest Health Protection