title: Field attractants for Pachnoda interrupta selected by means of GC-EAD and single sensillum screening.
abstract: The sorghum chafer, Pachnoda interrupta Olivier (Coleoptera: Scarabaeidae: Cetoniinae), is a key pest on sorghum, Sorghum bicolor (L.) Moench (Poaceae), in Ethiopia. At present there is a lack of efficient control methods. Trapping shows promise for reduction of the pest population, but would benefit from the development of attractive lures. To find attractants that could be used for control of P. interrupta, either by mass trapping or by monitoring as part of integrated pest management, we screened headspace collections of sorghum and the highly attractive weed Abutilon figarianum Webb (Malvaceae) for antennal activity using gas chromatograph-coupled electroantennographic detection (GC-EAD). Compounds active in GC-EAD were identified by combined gas chromatography and mass spectrometry (GC-MS). Field trapping suggested that attraction is governed by a few influential compounds, rather than specific odor blends. Synthetic sorghum and abutilon odor blends were attractive, but neither blend outperformed the previously tested attractants eugenol and methyl salicylate, of which the latter also was part of the abutilon blend. The strong influence of single compounds led us to search for novel attractive compounds, and to investigate the role of individual olfactory receptor neurons (ORNs) in the perception of kairomones. We screened the response characteristics of ORNs to 82 putative kairomones in single sensillum recordings (SSR), and found a number of key ligand candidates for specific classes of ORNs. Out of these key ligand candidates, six previously untested compounds were selected for field trapping trials: anethole, benzaldehyde, racemic 2,3-butanediol, isoamyl alcohol, methyl benzoate and methyl octanoate. The compounds were selected on the basis that they activated different classes of ORNs, thus allowing us to test potential kairomones that activate large non-overlapping populations of the peripheral olfactory system, while avoiding redundant multiple activations of the same ORN type. Field trapping results revealed that racemic 2,3-butanediol is a powerful novel attractant for P. interrupta.
authors.affiliation: Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden. Jonas.Bengtsson@ltj.slu.se
authors.forename: Jonas M
authors.initials: JM
authors.lastname: Bengtsson
authors.forename: Yitbarek
authors.initials: Y
authors.lastname: Wolde-Hawariat
authors.forename: Hamida
authors.initials: H
authors.lastname: Khbaish
authors.forename: Merid
authors.initials: M
authors.lastname: Negash
authors.forename: Bekele
authors.initials: B
authors.lastname: Jembere
authors.forename: Emiru
authors.initials: E
authors.lastname: Seyoum
authors.forename: Bill S
authors.initials: BS
authors.lastname: Hansson
authors.forename: Mattias C
authors.initials: MC
authors.lastname: Larsson
authors.forename: Ylva
authors.initials: Y
authors.lastname: Hillbur
mesh_terms: D000818:Animals; D002072:Butylene Glycols / Q000737:chemistry / Q000494:pharmacology; D002849:Chromatography, Gas; D001517:Coleoptera / Q000502:physiology*; D008401:Gas Chromatography-Mass Spectrometry; D019660:Malvaceae / Q000737:chemistry; D009812:Odorants; D018034:Olfactory Receptor Neurons / Q000502:physiology; D010571:Pest Control; D010675:Pheromones / Q000737:chemistry / Q000494:pharmacology; D014835:Volatilization
chemical_list: D002072:Butylene Glycols; D010675:Pheromones; C026978:2,3-butylene glycol