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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGEMENT OF INSECTS THAT ATTACK HORTICULTURAL, TURF, AND NURSERY CROPS

Location: Application Technology Research Unit

Title: Influence of flood-stress on ambrosia beetle host-selection and implications for their management in a changing climate

Authors
item Ranger, Christopher
item Reding, Michael
item Schultz, Peter -
item Oliver, Jason -

Submitted to: Agricultural and Forest Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 28, 2012
Publication Date: September 4, 2012
Repository URL: http://handle.nal.usda.gov/10113/56262
Citation: Ranger, C.M., Reding, M.E., Schultz, P., Oliver, J. 2012. Influence of flood-stress on ambrosia beetle host-selection and implications for their management in a changing climate. Agricultural and Forest Entomology. DOI: 10.1111/j.1461-9563.2012.00591.x.

Interpretive Summary: Xylosandrus germanus and other ambrosia beetles are key pests of ornamental nursery trees. Ethanol is the most attractive chemical known for X. germanus and other ambrosia beetles, and its emission from trees induces attacks by these wood-boring pests. Physiological stressors can induce trees to produce and emit ethanol, which could thereby predispose trees to attack by ethanol-responsive ambrosia beetles. In particular, observations from commercial nurseries have noted trees subjected to flood-stress and poor drainage were subsequently attacked by ambrosia beetles. Since extreme climatic events, including flooding, are predicted to increase for various regions of the US, a series of experiments were performed to examine the influence of flood-stress on the attractiveness and susceptibility of flowering dogwood, Cornus florida L. Results from our experiments demonstrated more ambrosia beetles were attracted to flood-stressed dogwoods than neighboring nonflooded controls in 2009, 2010, and 2011. Flood-stressed dogwoods were also preferentially attacked in 2009-2011, but no attacks occurred on any of the neighboring nonflooded trees. Ethanol was detected in tissue core samples from trunks of flooded dogwoods, but not nonflooded trees. Acetaldehyde, acetic acid, and ethanol were also detected in emissions from the bark of flooded dogwoods, but not nonflooded trees. These results demonstrate X. germanus preferentially lands on and attacks flood-stressed hosts over neighboring healthy trees. Minimizing the impact of stressors known to induce the production of ethanol and other stress-related volatiles should be the primary foundation of a management plan for X. germanus and other ethanol-responsive ambrosia beetles.

Technical Abstract: Xylosandrus germanus (Blandford) is a key pest of ornamental nursery trees. Ethanol is the most attractive semiochemical known for X. germanus and other ambrosia beetles, and its emission from trees represents an important host-selection cue. The production and emission of ethanol can be induced by a variety of abiotic and biotic stressors, which could thereby predispose trees to attack by ethanol-responsive ambrosia beetles. To better understand ambrosia beetle host-selection behavior within ornamental nurseries, a series of experiments were conducted to examine the influence of flood-stress on the attractiveness and susceptibility of flowering dogwood, Cornus florida L. Under field conditions, more X. germanus were attracted to and landed on experimentally flood-stressed dogwoods than neighboring nonflooded controls in 2009, 2010, and 2011. Flood-stressed dogwoods were also preferentially attacked in 2009-2011, but no attacks occurred on any of the neighboring nonflooded trees. Solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) detected ethanol in tissue core samples from trunks of flooded dogwoods, but not nonflooded trees. Acetaldehyde, acetic acid, and ethanol were also detected by SPME-GC-MS in bark emissions from flooded dogwoods, but not nonflooded trees. These results demonstrate X. germanus preferentially lands on and attacks physiologically-stressed hosts over neighboring healthy trees, and further supports the role of ethanol and potentially other stress-related volatiles in mediating this interaction. Minimizing stressors known to induce the production of ethanol and other stress-related volatiles should be the primary foundation of a management plan for X. germanus and other ethanol-responsive ambrosia beetles.

Last Modified: 7/30/2014
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