FACTORS INFLUENCING THE EFFICIENCY OF PHEROMONE-BAITED TRAPS FOR THREE SPECIES OF AMBROSIA BEETLES (COLEOPTERA: SCOLYTIDAE)

Abstract

AbstractThe optimal release rate of the aggregation pheromone, lineatin, for trapping Trypodendron lineatum (Olivier) was 40 μg/24h. Sticky vane traps were more efficient than three other trap types for T. lineatum and Gnathotrichus retusus (LeConte). For G. sulcatus (LeConte), a multiple funnel trap was more efficient than a sticky cylinder trap but no better than vane traps or Scandinavian drainpipe traps. Placement of bait in the middle or bottom of drainpipe traps increased their efficiency in capturing T. lineatum and G. sulcatus. Multiple funnel traps and drainpipe traps releasing lineatin at 10 μg/24h, with an additional dispenser releasing lineatin at 30 μg/24h 1.5–2 m away from the trap caught more T. lineatum than traps releasing lineatin at 10 μg/24h, and were as efficient as traps releasing the pheromone at 40 μg/24h. Thus, the beetles respond strongly to the trap silhouette once attracted to its vicinity. In late April traps placed 15–25 m inside the forest margin caught more T. lineatum than traps at the margin, probably intercepting overwintering beetles before they left the forest. A few strategically placed vane traps among numerous multiple funnel or drainpipe traps are recommended for mass trapping of ambrosia beetles in timber processing areas.