Associated Press – One of world’s top urban forests threatened by tiny beetle

washingtonpost.com – One of world’s top urban forests threatened by tiny beetle
nzherald.co.nz – One of world’s top urban forests threatened by tiny beetle
news957.com – One of world’s top urban forests threatened by tiny beetle

“One of the world’s largest urban forests is under threat from the polyphagous shot hole borer beetle which is thought to have made its way from Southeast Asia on packing crates or through the movement of plant materials. Many of the city’s estimated 6 to 10 million tress are dying and no one has found a way to combat the pest.”

Neil Shaw
2018-08-16
Associated Press

National Center for Biotechnology Information – Evaluations of Insecticides and Fungicides for Reducing Attack Rates of a new invasive ambrosia beetle (Euwallacea Sp., Coleoptera: Curculionidae: Scolytinae) in Infested Landscape Trees in California

2017-05-22
National Center for Biotechnology Information
Evaluations of Insecticides and Fungicides for Reducing Attack Rates of a new invasive ambrosia beetle (Euwallacea Sp., Coleoptera: Curculionidae: Scolytinae) in Infested Landscape Trees in California
“The combination of a systemic insecticide (emamectin benzoate), a contact insecticide (bifenthrin), and a fungicide (metconazole) provided some level of control when applied on moderate and heavily infested trees.”

University of California Division of Agriculture – polyphagous shot hole borer beetle

In July 2014 the University of California Division of Agriculture published the following information on the borer beetle problem:

Polyphagous Shot Hole Borer – PSHB in California

Polyphagous Shot Hole Borer + Fusarium Dieback
A New Pest Complex in Southern California

Polyphagous Shot Hole Borer + Fusarium Dieback
Field Identification Guide
Signs + Symptoms on 31 host trees in Southern California

 

Plant Disease – Host Range of Fusarium Dieback and Its Ambrosia Beetle (Coleoptera: Scolytinae) Vector in Southern California

2013-07
Plant Disease
Host Range of Fusarium Dieback and Its Ambrosia Beetle (Coleoptera: Scolytinae) Vector in Southern California
Akif Eskalen; Richard Stouthamer; Shannon Colleen Lynch; Paul F. Rugman-Jones; Mathias Twizeyimana; Alex Gonzalez; Tim Thibault
PDF Report

Abstract:
The polyphagous shot hole borer (PSHB) is an invasive ambrosia beetle that forms a symbiosis with a new, as-yet-undescribed Fusarium sp., together causing Fusarium dieback on avocado and other host plants in California and Israel. In California, PSHB was first reported on black locust in 2003 but there were no records of fungal damage until 2012, when a Fusarium sp. was recovered from the tissues of several backyard avocado trees infested with PSHB in Los Angeles County. The aim of this study was to determine the plant host range of the beetle–fungus complex in two heavily infested botanical gardens in Los Angeles County. Of the 335 tree species observed, 207 (62%), representing 58 plant families, showed signs and symptoms consistent with attack by PSHB. The Fusarium sp. was recovered from 54% of the plant species attacked by PSHB, indicated by the presence of the Fusarium sp. at least at the site of the entry hole. Trees attacked by PSHB included 11 species of California natives, 13 agriculturally important species, and many common street trees. Survey results also revealed 19 tree species that function as reproductive hosts for PSHB. Additionally, approximately a quarter of all tree individuals planted along the streets of southern California belong to a species classified as a reproductive host. These data suggest the beetle–disease complex potentially may establish in a variety of plant communities locally and worldwide.