Role of monoterpenes in Hylobius abietis damage levels between cuttings and seedlings of Picea sitchensis

This study investigated the role of monoterpenes, a group of chemicals known to be involved in plant defence, in the susceptibility of Sitka spruce [Picea sitchensis (Bong.) Carr.] plants derived from both cuttings and seedlings to attack by the large pine weevil Hylobius abietis (L.). Results showed that, given the choice, weevils prefer to feed on the shoots of seedlings than of cuttings and that this preference continued over a period of 6 days, although the overall level of feeding declined. This observation was associated with a higher level of monoterpenes in the shoots from cuttings than in those from seedlings. When the weevils were restricted to the stems and given no choice, levels of damage to the bark were similar in both plant types.