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Abstract
Successful infection of coast live oak (
Quercus agrifolia Née) stems by
Phytophthora ramorum results in the formation of a canker visible initially at the bark surface by the release of a dark red to black colored exudate referred to as "bleeding." Bark and ambrosia beetles are often attracted to diseased trees within the first year after bleeding cankers appear, and bore their gallery entrance holes almost exclusively within the canker boundaries, suggesting the presence of a primary attractant. These attacks accelerate tree mortality. Ethanol concentrations were analyzed in sapwood samples collected from paired diseased and healthy trees at three study sites in California. Samples from diseased trees were taken inside and outside of the boundaries of small spot cankers and larger cankers at the stem base. Trees with large basal cankers contained 4.3 times more sapwood ethanol than trees with spot cankers. Sapwood from within cankers had the highest concentrations, with 4.3 and 15.5 times more ethanol than sapwood from 1 cm or 15 to 30 cm outside the canker boundary, respectively. Paired healthy trees had the lowest sapwood ethanol levels.
Parent Publication
Citation
Kelsey, Rick G.; Beh, Maia; Shaw, Dave; Manter, Daniel K. 2013. Ethanol attracts scolytid beetles to
Phytophthora ramorum cankers on coast live oak [Abstract]. In: Frankel, S.J.; Kliejunas, J.T.; Palmieri, K.M.; Alexander, J.M. tech. coords. Proceedings of the sudden oak death fifth science symposium. Gen. Tech. Rep. PSW-GTR-243. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: p. 147.
