Category Archives: Moths

Guest blog: Hungry, hungry caterpillars (WA DNR)

close-up of a male Douglas-fir Tussock moth catepillar, undated.

The USDA Forest Service – Pacific Northwest Region helps monitor forest health in Washington and Oregon via annual aerial forest health surveys, conducted in partnership with with the Washington State Dept. of Natural Resources and the Oregon Dept. of Forestry. When signs of a widespread disease or insect pest activity are detected, more intensive monitoring programs may be established.

In this guest post from Washington State DNR, the state agency discusses about its efforts to trap, monitor, and collect better data on the patterns surrounding one such insect which periodically impacts the health of trees, especially in eastern Washington – the Douglas-fir Tussock moth.

From Washington State DNR:

“The life of a Douglas-fir tussock moth is not an easy one. The females can’t fly, and food is often scarce, not to mention viruses that make them explode. What’s more difficult than being a tussock moth, is having those moths in your forest.

“Every ten years or so, the tussock moth population skyrockets in some areas of eastern Washington, well beyond what the forest can support. When that happens, these insects can eat so much that they literally kill the fir trees they feed on, sometimes up to 40 percent in a single stand. If a tree is lucky enough to survive the infestation, they’ll then be much more vulnerable to disease, pests and wildfire.

“Often when we talk about species that destroy forests, those species are invasive. They didn’t come from the areas they’re killing. The tussock moth is actually a native species here in Washington, so what causes their once-in-ten-year eating rampage? We know that historically, the event happens approximately every ten years, but with a potentially disastrous ecological hazard, being as precise as possible is very important…”

Read more, on the agency’s “Ear to the Ground” blog:
https://washingtondnr.wordpress.com/2018/01/07/forest-health-the-hungry-hungry-caterpillar/

close up of a Douglas-fir Tussock moth on a conifer branch

An undated field photo of a male Douglas-fir Tussock moth. USDA Forest Service photo by David McComb (via Bugwood.org).

More information:

For more Douglas-fir Tussock Moth photos, check out this USDA Forest Service – Pacific Northwest Region Forest Health Flickr album: https://www.flickr.com/photos/151887236@N05/albums/72157685469658140

For photos from annual aerial health forest survey conducted jointly by the USDA Forest Service and Washington State, and surveys conducted with the State of Oregon, visit: https://www.flickr.com/photos/151887236@N05/albums/72157679829533950