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

Abstract

The importance of visual silhouettes for host finding by the southern pine beetle (SPB), Dendroctonus frontalis (Coleoptera: Scolytidae), and the potential for disruption of this process using visual deterrents were evaluated with multiple‐funnel traps, painted white or black, and with clear, white, or black Plexiglas sticky panels. All traps and panels were baited with the SPB attractant frontalure. The effect of combined semiochemical and visual disruption was evaluated in funnel traps by including the antiaggregation pheromone verbenone, or the repellent/inhibitory host compound 4‐allylanisole, in addition to the attractant. Visual treatments had a highly significant effect on catch of SPB and the predatory clerid beetle Thanasimus dubius. In attractant‐baited traps, white paint alone reduced the average number of SPB caught by 72% in Florida and 68% in Louisiana. The repellent 4‐allylanisole reduced catch of SPB by 56% in Florida and 45% in Louisiana. Verbenone was eluted at 25% of the targeted rate and did not affect total catch in either place. White panels trapped 79% fewer SPB than black, and 55% fewer than clear, with both differences significant. Clear panels also caught significantly fewer (−54%) SPB than black panels. Capture of T. dubius was reduced significantly by clear (−61%) or white (−56%) panels compared to black but did not differ significantly between clear and white panels. The percentage of female SPB captured was not significantly changed by visual treatments but was, as expected, reduced by verbenone. Neither visual nor semiochemical treatments influenced the sex ratio of T. dubius. The potential for using visual disruptants for protection of trees was assessed in front of a single SPB infestation by painting trees either white or black to 4.5 m. White trees showed fewer landings by SPB and a reduced density of successful and total SPB attacks within, but not above, the painted area. These results show that both SPB and T. dubius can be significantly affected by altering visual silhouettes, and that visual and semiochemical treatments, especially used in combination, may increase effectiveness of bark beetle disruption strategies.

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

“…The phenylpropanoid 4-allylanisole which naturally occurs in relatively small amounts within resin of host pines of D. frontalis was found to repel walking D. frontalis when it was applied to the walking surface, and furthermore devices releasing >100 mg/d of 4-allylanisole significantly reduced D. frontalis attraction to traps baited with frontalin and α-pinene (Hayes et al, 1994;Strom et al, 1999). Despite promising initial trials in which strings of releasers suspended along the tree bole appeared to prevent attacks on at-risk trees (Hayes et al, 1994;Strom et al, 1995), three different methods of deployment of 4-allylanisole (polymer/semiochemical-filled paintballs, microencapsulated semiochemical in a sprayable form, and vials attached directly to trees) releasing approximately 1-5 g/d/tree failed to demonstrate efficacy in protecting trees challenged either with D. frontalis attractant lures or through weakening with application of a toxin (N-methyldithiocarbamate) (Strom et al, 2004).…”

Small hive beetle,Aethina tumida, populations II: Dispersal of small hive beetles

“…Like other beetles, SHB may also use optical cues like sharp contrasts or light conditions (Strom et al, 1999;Igeta et al, 2003;Nalepa et al, 2005), resulting in constant higher infestation and re-infestation rates of colonies at certain positions in an apiary. If this is true, the relative distribution over the colonies should be similar at two consecutive surveys with colonies at attractive positions being repeatedly highly infested.…”

Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small‐scale movement behaviour

“…However, this similarity in shape may only appear to the human eye and not to the beetles, as they may even be able to use the spectral composition of the plant tissue for host plant recognition (Bullas-Appleton et al, 2004;Fischer et al, 2004;Mäntylä et al, 2004). Furthermore, the beetles may use a combination of olfactory and visual cues, which has also been found in other herbivorous insects (McIntyre & Vaughn, 1997;Cook & Neal, 1999;Strom et al, 1999;Barata & Araújo, 2001;Szentesi et al, 2002). As in this study only one host plant and one non-host plant individual were used, these questions cannot be finally answered, but further studies with several different plant individuals are needed to corroborate our results and to disentangle the olfactory and visual components of host plant recognition in C. canaliculata.…”