- Author: Beatriz Nobua-Behrmann
- Posted by: Karey Windbiel-Rojas
When tiny tree-killing beetles first arrived in Southern California several years ago and began destroying urban and riparian forests, they raised widespread concerns among both tree experts and affected communities. More recently, invasive shothole borers have captured far less attention, and many people may think the pest threat is over. Unfortunately, it's not!
While significant progress has been achieved in invasive shothole borer research, surveying, trapping, and management programs, these beetles are still an ongoing threat to the state's urban and wildland trees. Continue reading to find out what you can do to be part of the solution to this invasive pest issue.
What are invasive shothole...
(Credit: A Eskalen)
Small beetles are causing big problems in Southern California. Two closely related species, the polyphagous shot hole borer and the Kuroshio shot hole borer (collectively referred to as invasive shot hole borers), have been attacking more than 60 species of trees. These invasive beetles create a series of tunnels, or galleries, where they lay eggs and cultivate a Fusarium fungus to use as a food source. The fungus causes branch dieback, general tree decline, and can result in tree death. The beetles have been found in Los Angeles, Orange, Riverside, San Bernardino, Ventura, Santa Barbara, and San Diego counties.
What should you look for?
Invasive shot hole...
- Author: Beatriz Nobua Behrmann
[Originally published in the Fall 2018 issue of the Green Bulletin. Modified slightly from original.]
Invasive wood-boring beetles are attacking hundreds of thousands of trees in southern California, including commercial avocados, and trees within urban landscapes and wildland environments.
The invasive shot hole borers (ISHBs) consist of two closely related and morphologically identical species of beetles in the genus Euwallacea: the polyphagous shot hole borer and the Kuroshio shot hole borer. Despite their small size (1.8–2.5 mm) (Figure 1), these beetles are causing big...
[From the December 2016 issue of the UC IPM Green Bulletin]
The Polyphagous shot hole borer (PSHB) (Fig. 1) and Kuroshio shot hole borer (KSHB) are invasive wood-boring beetles that attack dozens of tree species in Southern California, including commercial avocado groves, common landscape trees, and native species in urban and wildland environments. Both beetles spread a disease called Fusarium Dieback (FD), which is caused by pathogenic fungi. Trees that are FD-susceptible may experience branch dieback, canopy loss, and tree mortality (Fig....
![Fig. 1 (a) Dying and dead Diplacus aurantiacus (orange bush monkeyflower) with advanced above ground symptoms, typical of Phytophthora disease. The infected plant has chlorotic (yellowing and browning) foliage. [L. Sims]](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/40702small.jpg)
[From the December 2016 issue of the UC IPM Green Bulletin]
A new plant pathogen in the genus Phytophthora (pronounced Fie-TOF-ther-uh) has recently been found in several California native plant nurseries and habitat restoration sites. The pathogen, Phytophthora tentaculata, poses a risk of disease in wildlands, gardens and landscapes that use susceptible California native and non-native plants. Once introduced in these areas, the pathogen can generate disease for years to come, potentially causing lasting environmental and economic...
