818-597-8627 INFO@RCDSMM.ORG


Help track the spread of Polyphagous/Kuroshio shot hole borers.

Around September 3, two new problems for our oaks, sycamores and willows were confirmed in Topanga: the polyphagus shot hole borer (PSHB) that infests many species of native and non-native trees, and the foamy bark canker disease caused by the western oak bark beetle (WOBB) that prefers oaks only. While each has a unique life history, they both involve a beetle infecting the tree with a fungus as food for their young.” Read Full Article in the Topange Messenger

Rosi Dagit

Senior Conservation Biologist, RCDSMM


Citizen Science Volunteers can help provide wider detection monitoring for PSHB throughout the Santa Monica Mountains by building and setting homemade traps.


The Polyphagous/Kuroshio Shot Hole Borer/Fusarium Dieback (PSHB/FD) is a non-native ambrosia beetle/fungi complex that has invaded southern California and is currently threatening tens of thousands of native, residential, and agricultural trees, and challenging our ability to sustain natural ecosystems and food systems. This invasive species complex is quickly reaching epidemic proportions, destroying entire riparian areas, and resulting in widespread environmental, economic, and aesthetic implications for the region. It was identified in Los Angeles County in 2003, becoming widespread after 2012. It was detected in Ventura County in late 2015 and in the Santa Monica Mountains (SMM) in 2016. We know that it attacks every native tree and some native shrubs found in the SMM (as well as some invasive plant species). No effective pesticide or fungicide treatment has been found to date. Rapid removal of the infected host tree to reduce the spread is currently the only management option. Therefore, our goals is to understand where the pest is currently found and to estimate its rate of spread early enough to respond effectively.


To do this, we need your help!  This is a great project for students!


To become a DETECTION DETECTIVE, please email Senior Conservation Biologist Rosi Dagit at rdagit@rcdsmm.org.
For trap instructions, click here.

Priority Tree Species to Monitor in the Santa Monica Mountains

  • Valley and Coast Live Oak
  • California Sycamore
  • All willows
  • Alders
  • Maples
  • Avocados
  • Mulefat
  • Castor Bean
  • Carrotwood

For a complete list of all tree species infested, and for more information on signs and symptoms for each species, go to www.pshb.org or  http://eskalenlab.ucr.edu/pshb.html


Click the icon above for step-by-step instructions.