Assessment of the Impact of Pheromone-Baited Trees on a Spruce Beetle Population (Coleoptera: Scolytidae)

Frontalin, a synthetic pheromone, induces attacks by the spruce beetle ( Dendroctonus rufipennis ) on baited standing trees, in which most broods fail. The impact of baiting 100 randomly chosen trees was determined by estimating the beetle population in a 766-ha spruce forest. Attack density in infested bark was similar for wind-thrown and baited trees; however, 95% of attacks occurred on the former, which were more numerous and had greater attacked surface areas. In this forest, it is estimated that 34 frontalin-baited trees would have been required for each windfall to trap 90% of the beetle population.