Granulate Ambrosia Beetle - The Dalles, Oregon

Adult granulate ambrosia beetle; photo by Natasha Wright, Florida Department of Agriculture and Consumer Services; bugwood.org

The granulate ambrosia beetle (GAB, Xylosandrus crassiusculus) is native to southern Asia, but since the mid-1970s it has become established in the U.S. in Maryland, Ohio, and many southern states. GAB attacks the stems of many hardwood species, and is on Oregon's "100 Most Dangerous Invaders" list; woody ornamentals, fruit and nut orchards, and nursery stock have sustained serious damage caused by GAB in the southeastern U.S. View additional information about GAB biology and damage from a pest alert, University of Florida website, or a N.C. State University website.

GAB was first detected in Oregon near a railroad tie production facility in The Dalles (Wasco County, north-central OR) in 1999 and 2000. Although trapping was immediately intensified in this area, no further GAB beetles were trapped until 2004 -- when 156 adults were found, along with much smaller numbers of other non-native wood-boring beetles. Prior to 2004, the railroad tie facility mostly processed conifers from various North American locations; starting in January 2004, however, this facility began processing mostly hardwood trees from the southeastern US -- and likely some of those "imported" hardwoods were infested with GAB.

Close-up view of an adult granulate ambrosia beetle; photo by J.R. Baker and S.B. Bambara, North Carolina State University; bugwood.org

The Oregon Department of Agriculture had lead responsibility for the eradication efforts aimed at GAB, with cooperation from USDA-APHIS, USDA Forest Service, and the railroad tie company. In July 2005, about 812 acres in and around the railroad tie facility were treated with Masterline Permethrin Plus-C, and the railroad tie stacks were treated with Perm-Up 3.2 EC. A second treatment was applied in September 2005 to 394 acres including the railroad tie facility and nearby areas, and a third treatment was applied in April 2006 to 860 acres in and around the facility. No GAB beetles were detected in The Dalles in 2006.

A key component to this eradication program was the voluntary cooperation of the railroad tie company. After the unprocessed hardwood ties from the southeastern U.S. were identified as the likely source of the GAB infestation, this company agreed to process those ties first. By October 2005, all of those high-risk ties had been heat-sterilized and creosoted. The company also implemented more stringent criteria for acceptable raw ties, with substandard ties either returned or destroyed immediately. In 2006, the company voluntarily halted importation of all raw hardwood ties from the southeastern U.S., pending development of effective treatments. The cooperation of the railroad tie company was essential to this successful eradication effort.