- Author: Sabrina L. Drill
Invasive shot hole borers (ISHB) are a pest and disease complex potentially affecting over 200 tree species, but posing a strong risk to box elders, sycamores, and other riparian and urban trees, as well as being a nuisance pest for avocado. The beetles have also been shown to attack a wide variety of common and less common ornamental species. (For a complete host list, visit https:// ucanr.edu/sites/pshb/overview/SHB_Reproductive_Hosts/). The tiny beetles burrow into the trunks and branches of trees, and create galleries where they cultivate a fungus that utilizes the tree's own circulatory system, harming and in some cases killing the tree. We know the beetle can reproduce in over 60 species of trees, and they have devasted natural riparian areas, though we are beginning to see recovery of some infestations. Currently, the most effective management method is to remove infested wood, sometimes entire trees, and chip what is removed to smaller than 1 inch.
Now there is a new resource for getting up to speed on ISHB, an on-line training! Available through our website, www.pshb.org, the course is actually served by the eXtension national online learning platform (and users will need to create a free account). The course consists of four chapters, including history and impacts, biology, symptoms and look-alike pests, and monitoring and management. While it can't fully replace field training, it can be a good way to get familiar with the issues.