Tags
dead Wych elm, Dutch Elm disease, elm bark beetle, elm bark beetle tunnels, Large elm bark beetle, Scolytus scolytus, Wych elm
After last Friday’s post about the Velvet shanks I’d found on a dead Wych elm, it occurred to me that I couldn’t recall seeing any traces of the elm bark beetles (likely the Large elm bark beetle Scolytus scolytus, according to an article on the Forest Research website) that carry the fungus that killed the tree. So, I went back for another look, and it turns out I hadn’t looked closely enough: there were signs of beetle activity all over the exposed areas of trunk where bark had fallen away and this showed up much more clearly on the darker underside of the bark itself.
During the summer, the female elm bark beetle drills a hole through the tree’s bark, then creates a long straight burrow (called the mother tunnel) under the bark. As she excavates, she lays eggs and, when the larvae hatch they create their own tunnels outwards from the mother tunnel. If the effects of their presence weren’t so deadly, the tunnels could almost be viewed as tiny works of art.
earthstar 
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