-
[show abstract]
[hide abstract]
ABSTRACT: A seven-state survey showed that the recently detected invasive Asian banded elm bark beetle, Scolytus schevyrewi Semenov, was abundant in areas of Colorado and Wyoming, whereas the long-established European elm bark beetle, S. multistriatus (Marsham), was not as abundant. In one of a series of studies to evaluate whether S. schevyrewi is competitively displacing S. multistriatus in their North American zone of sympatry, we characterized long-range flight responses infested or uninfested to small cut logs of American, Chinese, and Siberian elm, Ulmus americana, U. parvifolia, and U. pumila. Trials were conducted in Colorado and Wyoming to test the flight response of S. schevyrewi; in California to test the response of S. multistriatus; and in Nevada to test the responses of both species simultaneously. Studies with S. schevyrewi showed that males and females aggregated toward Ulmus spp. host volatiles but provided no evidence of a putative aggregation pheromone during the 0- to 48- or 48- to 96-h period of infestation. In contrast, S. multistriatus was attracted to U. pumila over unbaited controls, more to U. pumila infested with conspecific females than without, and more during the 48- to 96- versus 0- to 48-h period of infestation. This confirmed that male and female S. multistriatus aggregated toward host volatiles and that females produced an aggregation pheromone. In a cross-attraction study, S. schevyrewi displayed neither flight preference nor interruption to U. pumila infested with conspecifics, heterospecifics, or a mix of both species. Response of S. multistriatus was too low to draw conclusions. Although S. multistriatus aggregates moderately to host volatiles and strongly to female-derived pheromones emitted after a few days, S. multistriatus may have a relative disadvantage by selecting elm hosts more slowly than S. schevyrewi, which aggregates very strongly to host volatiles. The differential long-range host location strategy may be one factor in a chain of behavioral events that leads to advantageous host colonization and development by S. schevyrewi.
Environmental Entomology 04/2010; 39(2):642-52. · 1.56 Impact Factor
-
Jana C. Lee,
Ingrid Aguayo,
Ray Aslin,
Gail Durham,
Shakeeb M. Hamud,
Bruce D. Moltzan,
A. Steve Munson, José F. Negrón,
Travis Peterson,
Iral R. Ragenovich,
Jeffrey J. Witcosky,
Steven J. Seybold
[show abstract]
[hide abstract]
ABSTRACT: The invasive European elm bark beetle, Scolytus multistriatus (Marsham), was detected in Massachusetts a century ago, and it now occurs throughout the continental United States and southern Canada. The Asian banded elm bark beetle, Scolytus schevyrewi Semenov, was discovered in the United States in 2003, and now occurs in 28 states and the province of Alberta, Canada. Although the indigenous populations of these two species are allopatric, the invasive populations are now sympatric in North America where they co-colonize elm (Ulmus spp.) trees. A large-scale survey of these two Scolytus species was conducted with baited funnel traps, Plexiglas panel traps, and Ulmus pumila L. trap logs. Sites (four per locality) were monitored around Sacramento, CA; Reno, NV; Ogden, UT; Newcastle, WY; and Fort Collins, CO (2006-2007), and Manhattan, KS, and Columbia, MO (both only in 2007). Trap catches of S. schevrewyi relative to both Scolytus species captured from all three trapping methods at each survey site were 90 and 89% in Colorado, 90 and 83% in Wyoming, 60 and 68% in Utah, 43 and 68% in Nevada, and 11 and 13% in California (all in 2006 and 2007, respectively), and 3.3% in Kansas and 2.7% in Missouri (both only in 2007). Elevated abundances of S. schevyrewi at survey sites in Colorado and Wyoming could be the result of competitive displacement of S. multistriatus by S. schevyrewi, whose occurrence and mechanism require further study. General seasonal trends from all sites indicated peak flight in July and August for S. schevyrewi and two peaks (May-June and July-August) for S. multistriatus. 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 panel traps caught few beetles. The U. pumila trap logs were a more sensitive monitoring tool for detecting the presence of S. schevyrewi.
Annals of the Entomological Society of America 04/2009; 102(3):426-436. · 1.32 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: An exotic bark beetle from Asia, the banded elm bark beetle, Scolytus schevyrewi, has been discovered in 21 states of the United States. Although its point of entry is not known, a survey of museum specimens suggests that it has been in the US for at least 10 years. It is most abundant in western states, attacks primarily American and Siberian elms, and carries spores of the fungal pathogen for Dutch elm disease. In Colorado, S. schevyrewi appears to compete successfully with the more familiar smaller European elm bark beetle, Scolytus multistriatus. The host range, chemical ecology, and impact of S. schevyrewi are under investigation. The insect will likely have a significant deleterious effect on elms in the urban and peri-urban landscapes of North America.
American Entomologist. 05/2005; 51(2):84-94.
