Abstract:
Conifer bark beetles attack and kill mature spruce and pine trees, especially during hot and dry
conditions. These beetles are closely associated with ophiostomatoid fungi of the Ascomycetes, including the genera
Ophiostoma, Grosmannia, and Endoconidiophora, which enhance beetle success by improving nutrition and
modifying their substrate, but also have negative impacts on beetles by attracting predators and parasites. A survey
of the literature and our own data revealed that ophiostomatoid fungi emit a variety of volatile organic compounds
under laboratory conditions including fusel alcohols, terpenoids, aromatic compounds, and aliphatic alcohols. Many
of these compounds have already been shown to elicit behavioral responses from bark beetles, functioning as
attractants or repellents, often as synergists to compounds currently used in bark beetle control. Thus, these
compounds could serve as valuable new agents for bark beetle management. However, bark beetle associations with
fungi are very complex. Beetle behavior varies with the species of fungus, the stage of the beetle life cycle, the host
tree quality, and probably with changes in the emission rate of fungal volatiles. Additional research on bark beetles
and their symbiotic associates is necessary before the basic significance of ophiostomatoid fungal volatiles can be
understood and their applied potential realized.
