Progress 12/01/05 to 11/30/07
Outputs
OUTPUTS: The banded elm bark beetle (BEBB) is an invasive beetle from Asia, attacks elm trees, and may potentially vector the fungal pathogen causing Dutch elm disease. BEBB shares a similar biology to an established invasive, the European elm bark beetle (EEBB). However, BEBB seems to attack standing trees more aggressively and appears now more abundant than EEBB in the Rocky Mountain regions, suggesting that it may have displaced EEBB and/or is better able to colonize regions beyond EEBB's range. Our objectives were to determine (1) the relative abundance of BEBB and EEBB in seven states, (2) compare how each species locates host elms for attack, (3) compare how female adults select elms for colonization, (4) lay eggs at high densities and in the presence of the other species, and (5) compare the competitive ability of larvae developing in the same elm material. For objective 1, a trap Siberian elm log, baited funnel trap, and passive plexiglass trap were set up at four sites of
each state and monitored from April/May to September. BEBB was less common than EEBB in California (13%), BEBB increased in abundance from Nevada (68%) and Utah (65%), was highest in Colorado (89%) and Wyoming (83%), and then was scarce moving east to Kansas (3.3%), and Missouri (2.7%). This survey suggests that BEBB may be displacing EEBB since EEBB is no longer commonly found in Colorado when it was common in the past. For objective 2, flight towards uninfested and variously infested elm logs was monitored for BEBB in Colorado and Wyoming, and for EEBB in California. BEBB responded strongly to elm odors and showed no preference for elm infested with females or males. EEBB responded somewhat to elm odors but more so to pheromones from an elm that was infested by EEBB females for 48-96 hr. Colonizing female EEBB required a few days to produce an attractive pheromone. Lastly, in Nevada, BEBB responded indiscriminately to any elm log regardless of it being infested with BEBB, EEBB, or
both. Thus, when a new elm is available, BEBB may have a competitive advantage and fly towards it in great numbers initially, whereas EEBB may fly in great numbers after a few days following pheromone production. In laboratory studies for objective 3, both EEBB and BEBB female appeared to colonize uninfested elms at similar rates. A second group of females were introduced to infested elms, and both EEBB and BEBB colonized at similar rates regardless of it being infested by the same or opposite species. For objective 4, both EEBB and BEBB did not adjust their egg laying behavior at medium or high densities, or in elm bolts when both species were present. For objective 5, BEBB larva was a superior competitor to EEBB larva when both species colonized the same elm. Results of this study have been presented with 5 talks and 6 posters at the Entomological Society, California Forest Pest Council, Great Plains Tree Pest Council, and UC Davis Seminar. Outreach includes presenting management
recommendations at 4 Professional Association of Pesticide Applicators workshops, and making "Pest Alert" and "Forest Insect and Disease Leaflet" extension pamphlets.
PARTICIPANTS: Ingrid Aguayo - Colorado State Forest Service; Ray Aslin - Kansas State Forest Service; Steve Churchillo - Reno Parks and Recreation; Gail Durham - Nevada Division of Forestry; Shakeeb Hamud - USDA Forest Service, Davis, CA; Bruce Moltzan - Missouri Department of Conservation; A. Steve Munson - USDA Forest Service, Ogden, UT; Jose Negron - USDA Forest Service, Ft. Collins, CO; Travis Peterson - Newcastle Aborist, WY; Iral Ragenovich - USDA Forest Service, Portland, OR; Jeff Witcosky - USDA Forest Service, Lakewood, CO; Steven Seybold - USDA Forest Service, Davis, CA
TARGET AUDIENCES: Knowing the status of banded elm bark beetle through seven states, and its attraction to elm volatiles is useful to pest and landscape managers, foresters, and homeowners. We have worked with state and federal cooperators on a better way to monitor for this invasive bark beetle. Understanding the mechanisms of competitive displacement and the interactions between the two species will bring addition advances to invasive species ecology. Knowledge gained during these studies on Banded elm bark beetle have been delivered to the general public in a 2-page "Pest Alert" and 12-page "Forest Insect and Disease Leaflet".
PROJECT MODIFICATIONS: 1. Proposed Objective 1 field survey of beetles in California, Nevada, Utah, and Colorado More states were added to the survey than originally proposed to provide more information about the distribution of the new invasive beetle. In 2006-07, sites in Wyoming were added. And in 2007, sites in Kansas and Missouri were added. 2. Proposed Objective 2.2 on studying the mating selection of the two species Mating was difficult to observe without disturbing the beetles on the logs. Instead of observing mating, egg laying patterns were observed with beetles in medium, high, and mixed density treatments. Also, cross paired beetles (ie. pairing female BEBB with male EEBB) were also observed for egg laying patterns. 3. Proposed Objective 3 on the differential natural enemy pressure on BEBB and EEBB The proposed studies were conducted in the field. We choose to lay BEBB-infested or EEBB-infested test logs in a California test site where a particular parasitoid was often
found. Unfortunately, the parasitoids were very sporadic and only one log was attacked by them. From this study, we cannot conclude if there is any difference in natural enemy pressure on the bark beetles. It was possible that infested logs were removed too early from the field, and the main parasitoid attacked later-stage larvae and pupae. However, we choose to expose infested logs no longer than 25 days of infestation, so that none of the beetles inside the log would complete development and get introduced into the area.
Impacts
PROGRESS: 2006/12 TO 2007/12 The seven-state monitoring survey indicated that Colorado and Wyoming are highly impacted by the invasive banded elm bark beetle (BEBB), and that BEBB is possibly rising in Utah and Nevada. Thus far, BEBB is not as common in California and infrequently found in Kansas and Missouri. However, BEBB should be continually monitored in these areas. Given the competitive advantage of BEBB over the European elm bark beetle (EEBB) in finding elms at long distances, and the ability of BEBB larvae to outcompete EEBB larvae, BEBB may increase in prevalence over time. The potential increase of BEBB in various parts of the U.S. may affect the incidence of Dutch elm disease since adult BEBB have been found carrying spores of the causative agent. We have alerted pest and landscape managers, foresters, and homeowners about this pest through several extension publications, and while visiting parks, golf courses, residences, and waste facilities. Also, this
project included many state, city, and federal forestry cooperators whom have also informed their coworkers and the public about the potential threat of BEBB. Understanding what cues the banded elm bark beetle uses to locate elm trees will help pinpoint how the pest beetle may be disrupted from attacking trees. Our field tests suggest that the beetle does not respond to pheromonal cues but very strongly to elm odors. Thus, monitoring traps used for early detection of this invasive should include high release rate of elm volatiles.
Publications
- PUBLICATIONS (not previously reported): 2006/12 TO 2007/12 Lee, J.C., M.L. Flint and S.J. Seybold. Host suitability of pines and other conifers for the invasive Mediterranean pine engraver. Journal of Economic Entomology, in press.
- PROJECT CONTACT: Name: Jana C. Lee Phone: 541-738-4110 Fax: 541-738-4025 Email: jana.lee@ars.usda.gov SUPPLEMENTARY DATA: Institution Type: SAES Region: 4 Process Date: 2005/08/12 Progress Update: 2008/01/25 Program Code: 51.2
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Progress 12/01/05 to 12/01/06
Outputs
The banded elm bark beetle (BEBB) is an invasive beetle from Asia, attacks elm trees (Ulmus spp.), and may potentially vector the fungal pathogen causing Dutch elm disease. BEBB shares a similar biology to an established invasive, the European elm bark beetle (EEBB). However, BEBB seems to attack standing trees more aggressively and appears now more abundant than EEBB in the Rocky Mountain regions, suggesting that it may have displaced EEBB and/or is better able to colonize regions beyond EEBB's range. Our objectives were to determine (1) the relative abundance of BEBB and EEBB in California, Nevada, Utah, Colorado and Utah, and (2) compare how each species locates host trees for attack. A trap Siberian elm log, baited funnel trap, and passive plexiglass trap were set up at four sites of each state and monitored from May to September. BEBB was far less common than EEBB in California (12%), and BEBB increased in abundance from Nevada (43%), Utah (60%), Colorado and
Wyoming (90%). The attraction of BEBB and EEBB to hosts American elm, U. americana, and Siberian elm, U. pumila, and the same hosts infested with conspecifics were tested with flight traps. In Colorado and Wyoming, BEBB was very attracted to Siberian elms bolts alone or infested with consepecifics. This suggests that BEBB is responding to host odors and not pheromonal cues during the initial stages of infestation. In California, EEBB was most attracted to Siberian elm bolts infested with other EEBB, and attracted to a lesser degree to uninfested Siberian elm bolts. This suggests that EEBB was responding to host cues, and even more to pheromonal cues.
Impacts
Our banded elm bark beetle monitoring across five states have identified Colorado and Wyoming as areas highly impacted, and we have alerted pest and landscape managers, foresters, and homeowners. Understanding what cues the banded elm bark beetle uses to locate elm trees will help pinpoint how the pest beetle may be disrupted from attacking trees. Our recent field tests suggests that the beetle does not respond to pheromonal cues and additional work will focus on developing attractant baits with elm host cues for pest management.
Publications
- Lee, J.C., R.A. Haack, J. Negron, J.Witcosky and S.J. Seybold. 2007. Invasive bark beetles. USDA Forest Service, Forest Insect and Disease Leaflet, 176, in press.
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