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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #233261
Title: Co-occurence of Two Invasive Species: The Banded and European Elm Bark Beetles (Coleoptera: Scolytidae)

Author
item Lee, Jana
item AGUAYO, INGRID - COLORADO FOREST SERVICE
item ASLIN, RAY - KANSAS FOREST SERVICE
item DURHAM, GAIL - NEVADA FORESTRY
item HAMUD, SHAKEEB - USDA FOREST SERVICE
item MOLTZAN, BRUCE - MISSOURI CONSERVATION
item MUNSON, STEVE - USDA FOREST SERVICE
item NEGRON, JOSE - USDA FOREST SERVICE
item PETERSON, TRAVIS - NEWCASTLE FORESTRY
item RAGENOVICH, IRAL - USDA FOREST SERVICE
item WITCOSKY, JEFFREY - USDA FOREST SERVICE
item SEYBOLD, STEVEN - USDA FOREST SERVICE

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2009
Publication Date: 5/5/2009
Citation: Lee, J.C., Aguayo, I., Aslin, R., Durham, G., Hamud, S., Moltzan, B., Munson, S., Negron, J., Peterson, T., Ragenovich, I., Witcosky, J., Seybold, S. 2009. Co-occurence of two invasive species: the banded and European elm bark beetles (Coleoptera: Scolytidae). Annals of the Entomological Society of America. 102:426-436.

Interpretive Summary: The European elm bark beetle, originally from Europe, was first discovered in Massachussetts a century ago and has since spread throughout the continental United States. It feeds and reproduces in the phloem layer of elm trees and has vectored Dutch elm disease, devastating American elm populations throughout the North and Northeastern United States. In 2003, the banded elm bark beetle, originally from Asia, was first discovered in Utah and Colorado. Now it is known to occur in 23 states and has been found killing drought-stressed elms. Earlier observations in the field indicate that the new banded elm bark beetle is now abundant in areas previously heavily infested by the European elm bark beetle. Since both species inhabit the phloem layer of elms, they may be competing for resources. The objective of our study was to document the relative abundance of both species across a transect through five states in 2006 and seven states in 2007 (addition of Kansas and Missouri). Four sites within 60 miles of each other per state were monitored: Sacramento, California; Reno, Nevada; Ogden, Utah; Newcastle, Wyoming; Denver, Colorado; Manhattan, Kansas; and Columbia, Missouri. Each site had a baited funnel trap, passive plexiglass trap, and trap elm log. Overall, abundance of the banded elm bark beetle was 83-90% in Colorado and Wyoming, 43-68% in Nevada and Utah, 11-13% in California, and 3% in Kansas and Missouri. These trends may indicate that the banded elm bark beetle could have displaced the European elm bark beetle in some areas and is just starting to invade areas such as California, Kansas and Missouri. Baited funnel traps were most sensitive to detecting the European elm bark beetle, and trap logs were most effective for detecting the banded elm bark beetle.

Technical Abstract: The invasive European elm bark beetle, Scolytus multistriatus (Marsham), was first detected a century ago and now occurs in most of the continental United States. The invasive banded elm bark beetle, Scolytus schevyrewi Semenov, native to Asia, was discovered in the United States in 2003 and is now known to occur in 23 states. Although the indigenous populations of these two species are largely allopatric, the invasive populations are now sympatric, primarily in the western United States where they co-colonize American and Siberian elms, Ulmus americana L. and U. pumila L. A large-scale survey of these two species of Scolytus was conducted with baited funnel traps, passive plexiglass traps, and U. pumila trap logs in sites with elm trees or cut elm stem wood or branches. Four sites within a 1.2-49 km radius were monitored around Sacramento, California; Reno, Nevada; Ogden, Utah; Newcastle, Wyoming; and Denver, Colorado in 2006-2007; and around Manhattan, Kansas; and Colombia, Missouri in 2007. Mean relative abundance of S. schevyrewi out of all captured Scolytus from all three trapping methods was 90% and 89% in Colorado in 2006 and 2007, respectively. Relative abundance was 90% and 83% in Wyoming, 60% and 68% in Utah, 43% and 68% in Nevada, 11% and 13% in California (in 2006 and 2007, respectively), 3.3% in Kansas (2007), and 2.7% in Missouri (2007). Trends in Colorado and Wyoming could be the result of competitive displacement of S. multistriatus by S. schevyrewi. Funnel traps baited with Multilure and 2-methyl-3-buten-2-ol were highly attractive to S. multistriatus, and mildly attractive to S. schevyrewi, whereas plexiglass traps caught few Scolytus spp. Ulmus pumila trap logs detected the presence of S. schevyrewi even when flight traps did not, which suggests that trap logs would be a more sensitive monitoring tool for the new invasive bark beetle.