Can pheromones and host volatiles induce Monochamus species (Cerambycidae:Lamiinae) to colonize healthy shortleaf pines?

Monochamus carolinensis and Monochamus titillator are large wood-boring beetles which are commonly associated with dead or dying pine trees in the southeastern United States.  While studies have traditionally classified Monochamus as secondary insects, recent reports have placed Monochamus species as primary pests in other geographical areas.  Our objectives are to test the ability of Monochamus to colonize apparently healthy shortleaf pine trees and to evaluate the role of attack rate in overcoming tree defenses.  A total of 48 trees were divided among four plots of mixed pine forest within USDA Forest Service managed areas in the Ozark-St. Francis National Forest in Arkansas.  Lure combinations containing Monochamus sex pheromones, ethanol, Ipsenol, and cis-3-pinene-2-ol were placed ~7 meters above the ground on the bole of healthy shortleaf pine trees.  Trees were treated with lures during one of two Monochamus flight periods. Trees were monitored biweekly for two months to assess overall tree health and count oviposition pits. Trees are being felled and destructively sampled to determine the success of colonization by Monochamus.  We predict two possible outcomes: tree defenses successfully inhibiting the development and survival of Monochamus within the tree or Monochamus larvae successfully overcoming tree defenses, fully developing, and most likely killing the tree.  Determining the ability of Monochamus to colonize healthy pines adds to our knowledge base of this ecologically significant forest insect.