Monitoring spruce budworm (Lepidoptera: Tortricidae) populations with pheromone-baited traps

Field trials with four types of pheromone traps and two types of commercial lures were evaluated to develop a population-monitoring technique for spruce budworm, Choristoneura fumiferana (Clemens). When data were stratified by state or province, mean catch in several treatments (trap model/lure combinations) was significantly correlated with densities of larval stages L3-L4 (generations n and n + 1) and L2. Relationships varied among regions and hosts. There was no significant difference in moth catch between traps within five-trap clusters when traps were spaced 40 m apart. Within-cluster variation in traps catch was high; coefficients of variation averaged 35% for the covered funnel trap/Conrel lure treatment and 49% for the covered funnel trap/Hercon lure treatment. Application of pheromone-baited traps to monitor spruce budworm populations is discussed and recommendations are made to improve the monitoring system.