Relationship of host tree diameter to within-tree southern pine beetle (Coleoptera: Scolytidae) population dynamics

Abstract

Relationships of host-tree diameter and season to within-tree southern pine beetle, Dendroctonus frontalis Zimmermann, population parameters (successful attack, egg, and emerging brood adult densities, attacking adult and within-tree brood mortality, and brood increase ratio) were studied in 2 infestations. Relationship of tree diameter at breast height to beetle population parameters differed considerably between infestations. Beetles were not adversely affected by host trees as small as 15.2-cm diameter at breast height. Values of beetle population parameters varied widely among trees. Season was as influential as host-tree diameter on beetle population parameters. Winter and spring values of brood increase ratio in each of the infestations corresponded with spot growth patterns in the infestations. Winter or spring, or both, values of brood increase ratio were higher than summer values.