Influence of Fusarium and Wheat Stem Sawfly Infestation on Volatile Compounds Production by Wheat Plants

Plants that were infested by the wheat stem sawfly emitted significantly increased amounts of the secondary metabolites linalool, linalool oxide, ß-farnesene, ß-caryophyllene, and 4-heptanone in comparison to uninfested plants. Wheat plants parasitized by Fusarium species also have emitted volatiles. The amount of volatiles released varied by infective species of Fusarium and volatile patterns varied over time for both sawfly infestation and pathogen infection. Plants that were stressed by both herbivory and pathogens emitted even greater amounts of certain volatiles. Surprisingly, larval sawfly mortality was much greater in plants infected by Fusarium species, and both mortality and the rate of volatile release varied by Fusarium. The role of these plant volatiles are further discussed in the context of defensive plant responses to Fusarium and sawfly infestation.