Areawide Efficacy of a Localized Forest Pest Management Practice

Semiochemicals in the Natural History of Southern Pine Beetle Dendroctonus frontalis Zimmermann and Their Role in Pest Management

“…Because of the short generation time of this species, it is possible for mass attacked and therefore aggregation pheromone-producing trees to still be present within a spot when the first generation of brood emerge (Franklin, 1970). It has been shown that emerging brood beetles tend to remain concentrated in the area where they emerge if a source of aggregation pheromone is present; otherwise they disperse into the surrounding forest (Cronin et al, 1999;Gara, 1967). Thus a high proportion of these emerging brood fly to the nearby mass-attacked trees [typically less than 50 m away (Ayres et al, 2011)] and continue the process of mass attack and host switching initiated by their parents (Franklin, 1970).…”

“…It has been demonstrated that removal of the currently mass-attacked trees (ie, the source of aggregation pheromone) within an infestation can often be a sufficient measure to stop spot growth (Clarke et al, 1999;Cronin et al, 1999;Gara, 1967). In addition, the recommended cutting of a "buffer" of unattacked trees in advance of the massattacked trees increases the distance of the nearest suitable host tree to the natural source of D. frontalis attractant.…”

“…In "cut-and-remove", all infested trees and the buffer are removed from the site thereby eliminating both the natural source of the aggregating pheromone and the major source of beetles that would be aggregated by it. This method is of course ideal from the standpoint that removed trees can often be salvaged and brood beetles that would otherwise disperse from infested trees and potentially do harm in the surrounding forest are eliminated (Cronin et al, 1999;Gara, 1967). Cut-and-leave is used when tree removal is not practical or economical; trees occupied by beetles and the buffer trees are all felled opposite the direction of spot growth but left in place.…”

“…Cut trees are reported to rapidly lose attractiveness (Vit e and Crozier, 1968), however, other reports indicate that downed timber can sustain mass attacks (Moser, 1987). Emergent beetles from felled brood trees tend to disperse rather than regenerate a new head at the same location (Cronin et al, 1999), however the need for retreatment is more common for cut-and-leave than cut-and-remove (Clarke, 2001;Clarke and Billings, 2003). Nonetheless, the major mechanism underlying the success of both methods appears to be interruption of the beetles' semiochemical communication.…”

Variable Responses by Southern Pine Beetle, Dendroctonus frontalis Zimmermann, to the Pheromone Component endo-Brevicomin: Influence of Enantiomeric Composition, Release Rate, and Proximity to Infestations

“…A prevailing background of D. frontalis semiochemicals presumably exists within the microenvironment of infestations but not in the surrounding forest. Trees within the advancing head of an infestation may contain many thousands of pheromone-producing beetles (Pureswaran et al, 2008), and evidence indicates that the associated semiochemical plume can profoundly influence behavior of D. frontalis orienting within and near these infestations (Gara et al, 1965;Gara, 1967;Cronin et al, 1999). These background semiochemicals conceivably could alter beetle responses to point sources of semiochemicals established within the infestation, such as our baits.…”