Orientation of bark beetlesPityogenes chalcographus andIps typographus to pheromonebaited puddle traps placed in grids: A new trap for control of scolytids

Abstract

Abstract--A puddle trap was designed that is simple to build and efficient in catching bark beetles (Coleoptera: Scolytidae). The trap is insensitive to wind and should be much easier to manufacture than the more complicated perforated pipe and barrier traps commercially available. A 7 • 7 grid of 49 puddle traps baited with aggregation pheromone components of Pityogenes chalcographus (chalcogran and methyl decadienoate) was placed at either 1.5-, 3-, 6-, or 12-m spacing between traps in the field for two or more replicates of one day length (June 1989, Torsby, Sweden). The resulting catches showed that beetles were trapped as they flew into the grid since the inner square-ring of 24 traps caught less beetles per trap than the outer square-ring trap average (36 traps) in most experiments, lps typographus also landed in puddle traps primarily on the periphery of the grid (6-m spacing only) when traps were baited with its pheromone components, (S)-cis-verbenol and methyl butenol.Computer simulation of flying bark beetles in grids of traps of various spacings and catch radii estimated that the experimental pheromone traps had an effective catch radius of 1.3 m or less for P. chalcographus, depending on the spacing between traps. An effective catch radius of 2 m for L typographus was found for the 6-m grid spacing. P. chalcographus beetles were increasingly disrupted in their orientation to pheromone at the closer trap spacings since the effective catch radius declined linearly with closer trap spacing. However, landing was still precise since unbaited puddle traps within the grid did not catch any bark beetles.

Spatial analysis of mass trapping: how close is close enough?

“…46 In another study with a forest system, effects were seen at even greater distances. 47 Bark beetles trapped with pheromones in 7 × 7 trap arrays showed higher catches at corners in many plots, 48 similarly to the results seen here, and apparently predictable by the geometry, as in our case with the 4 × 4 array. In an open field situation with oriental fruit moth, active flight distances of up to 80 m to a sex pheromone lure were observed, 35 and for Cydia nigicana the attraction range of males to their sex pheromone was estimated to be 200 m with stimulation (response to but not necessarily directed movement towards the odour source) from 400 m away.…”

Relative Suitability of Virginia Pine and Loblolly Pine as Host Species forDendroctonus frontalis(Coleoptera: Scolytidae)

“…In site 3, where the pine species were largely segregated into different halves of a 1-ha area, Þnal attack densities were no different between species (Table 2). We hypothesize that these sites differed because beetles choose among trees at a relatively Þne spatial scale (Byers 1993(Byers , 1999, but it might also be attributable to season (the segregated site was attacked 6 Ð 8 wk earlier than the intermixed site), or chance variation in the local abundance of ßying beetles (Borden et al 1986). There would be value in comparing beetle attack preferences for these two species across replicate stands drawn from a broader forest landscape than was studied here.…”

Visual and Semiochemical Disruption of Host Finding in the Southern Pine Beetle

“…Closely related, less aggressive species (e.g., Ips pini (Say) and Ips perroti Swaine) that readily attack nonvertical host material, but have similarly limited host species ranges, do not seem to be as affected by our visual treatments (B. D. Ayres, unpublished data ). Byers (1993) used baited “puddle” traps, apparently without any silhouette, to effectively capture I. typographus, suggesting that this species is not affected by visual silhouettes when aggregation pheromone is present. Whether these patterns of attack and trap results are related to these Ips spp.…”