Bugs on ash tree - Ask Extension
I noticed these beetles all over our tree near the street. What are they and what should we do?
Knowledgebase
Bugs on ash tree #864328
Asked April 12, 2024, 11:56 PM EDT
I noticed these beetles all over our tree near the street. What are they and what should we do?
Washington County Oregon
Expert Response
Hi Bridget,
Great pics!
Those are longhorned beetles (Family: Cerambycidae) called western ash borers (Neoclytus conjunctus). This is a species with larvae that bore into and feed on the wood of dead ash trees and a few other species. They are not considered a pest of healthy ash trees.
Here is a bit more information from an OSU publication on ash tree health...
The western ash borer, Neoclytus conjunctus (Coleoptera: Cerambycidae), is known to utilize dead ash, oak (Quercus species) and madrone (Arbutus menziesii) from British Columbia to southern California. That insect is not considered a threat to tree health. Western ash borer adults are black with bold white or yellow “O”-shaped markings at the base of the elytra. They measure 7–18 mm long (Figure 11). The insect is attracted to
freshly cut wood and may arrive while the chain saws are still working. The larvae can riddle the sapwood of freshly cut, bark-covered, unseasoned wood. Adults can emerge from firewood stored inside houses up to two or more years after cutting. Our native wood-boring insects may be opportunistic feeders of stressed trees but do not significantly contribute to tree mortality.
So it seems like you can just enjoy these beautiful native insects and don't have to do anything to control them. If your trees seem to be dead or dying, you could check this publication to see if you can determine what is causing the problem...
https://extension.oregonstate.edu/catalog/pub/em-9380-oregon-ash-insects-pathogens-tree-health
Hope that helps!
Great pics!
Those are longhorned beetles (Family: Cerambycidae) called western ash borers (Neoclytus conjunctus). This is a species with larvae that bore into and feed on the wood of dead ash trees and a few other species. They are not considered a pest of healthy ash trees.
Here is a bit more information from an OSU publication on ash tree health...
The western ash borer, Neoclytus conjunctus (Coleoptera: Cerambycidae), is known to utilize dead ash, oak (Quercus species) and madrone (Arbutus menziesii) from British Columbia to southern California. That insect is not considered a threat to tree health. Western ash borer adults are black with bold white or yellow “O”-shaped markings at the base of the elytra. They measure 7–18 mm long (Figure 11). The insect is attracted to
freshly cut wood and may arrive while the chain saws are still working. The larvae can riddle the sapwood of freshly cut, bark-covered, unseasoned wood. Adults can emerge from firewood stored inside houses up to two or more years after cutting. Our native wood-boring insects may be opportunistic feeders of stressed trees but do not significantly contribute to tree mortality.
So it seems like you can just enjoy these beautiful native insects and don't have to do anything to control them. If your trees seem to be dead or dying, you could check this publication to see if you can determine what is causing the problem...
https://extension.oregonstate.edu/catalog/pub/em-9380-oregon-ash-insects-pathogens-tree-health
Hope that helps!
