Trees in the Willamette Valley are susceptible to a variety of pests and pathogens. One that has caught our eye in recent years is European Shothole Borer or Pear blight beetle (Anisandrus dispar). This species, which used to be called Xyleborus dispar until recently, is an exotic from Eurasia and was probably brought to North America by the earliest European settlers and the fruit trees they brought with them. In the past, it was a significant pest of fruit orchards, delighting in the name “pear blight beetle”. Now, these beetles attack a host of other fruit and shade trees. This beetle overwinters in a suitable host and, on one of the first warm days of spring, attack host trees that exhibit signs of stress. Once the female beetle finds a suitable host, she will send out a pheromone that attracts hundreds of additional beetles, killing the tree very quickly.
Management: Since this beetle attacks stressed trees, it’s imperative to keep your trees as healthy as possible! Trees that are drought-stricken, water logged, or have root and basal damage are much more attractive to this beetle.
If you suspect your street tree has these beetles, or for more information,
Jennifer Killian
Urban Forestry and Natural Areas Specialist Jennifer.killian@corvallisoregon.gov 541-740-3186
From Civic Beautification and Urban Forestry Advisory Group Meetings: 2nd Thursday of the month from 9-10:30am www.corvallisoregon.gov/bc-cbufdac
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