Scientists & Staff

Steve Seybold

Notes: This person is no longer an employee of the Northern Research Station.

Publications & Products

National Research Highlights

Dark sap staining on the bark surface of a walnut tree (Pterocarya stenoptera) branch caused by underlying damage from the walnut twig beetle (Pityophthorus juglandis) and fungus (Geosmithia morbida) surrounding two beetle entrance or emergence holes.

Wingnut trees at risk to thousand cankers disease

Year: 2017

The walnut twig beetle vectors a fungus that colonizes and kills the plant tissure known as phloem of walnut and butternut trees. Over the past two decades this condition, known as thousand cankers disease, has led to the widespread mortality of walnut trees (Juglans) in the U.S.. Recently the beetle and pathogen were discovered in three species of wingnut (Pterocarya) trees in the walnut family, in northern and southern California.

An adult goldspotted oak borer, an exotic insect threatening red oaks in California. T.W. Coleman, USDA Forest Service

Delimiting the invaded range of the goldspotted oak borer, a threat to red oaks in California and Oregon

Year: 2014

The goldspotted oak borer, Agrilus auroguttatus, traveled in infested firewood from southeastern Arizona into southern California where it is killing coast live oak and California black oak trees. Forest Service staff members and partners developed a trapping system used it to monitor the insect's range. The survey showed that the pest is limited to Riverside and San Diego counties.

Lures slowly releases male-produced aggregation pheromone of the walnut twig beetle. Stacy M. Hishinuma, Steven J Seybold, USDA Forest Service

Scientists Develop Successful Lure to Attrack Beetle That Causes Thousand Cankers Disease in Walnut Trees

Year: 2013

In response to the threat posed by the walnut twig beetle, which spreads thousand cankers disease in walnut trees, the Forest Service's Pacific Southwest Research Station developed a highly effective lure for the beetle. This synthetic form of a pheromone created by the male beetles will allow for much faster detection and mapping of this invasive insect, which has expanded its known distribution from four U.S. counties in 1960 to 100 counties by September 2013.

Monitoring Tool for the Insect Vector of Thousand Cankers Disease of Walnut

Year: 2011

A newly discovered pheromone can be used to detect the insect vector of thousand cankers disease of walnut. Intermediate and low population density populations can be found enabling early detection and rapid response to this destructive walnut pest complex.

Last modified: Friday, June 28, 2013