Ethanol attracts scolytid beetles to Phytophthora ramorum cankers on coast live oak

Abstract

Ethanol in sapwood was analyzed along vertical transects, through small spot cankers and larger basal cankers, of Phytophthora ramorum-infected stems of Quercus agrifolia at three sites in California. Trees with large basal cankers, known to attract scolytid beetles, had a 4.3 times higher ethanol level than trees with spot cankers that attract fewer beetles. We conclude that ethanol in P. ramorum cankers functions as a primary host attractant for scolytid beetles and is an important link in colonization of these cankers and accelerated mortality of Q. agrifolia. The results of this research shed light on the chemical ecology behind the focused scolytid attacks on P. ramorum-infected coast live oaks, and lay the groundwork for future efforts to prolong the survival of individual trees of this keystone species.

Citation

Kelsey, Rick G.; Beh, Maia M.; Shaw, David C.; Manter, Daniel K. 2013. Ethanol attracts scolytid beetles to Phytophthora ramorum cankers on coast live oak. Journal of Chemical Ecology. 39(4): 494-506.