Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2006
Publication Date: 9/14/2006
Citation: Keum, Y., Mcquate, G.T., Li, Q.X. Isolation and indentification of synergists for the parapheromone alpha-ionol from cade oil for male bactrocera latifrons (diptera: tephritidae). Pest Management Science.
Interpretive Summary: Compounds primarily attractive to males are known for many tephritid fruit fly species. For the solanaceous fruit fly, Bactrocera latifrons, the best male attractant known to date has been a combination of the chemicals alpha-ionol, sometimes referred to as latilure, and cade oil. The cade oil had previously been found to synergistically enhance the attractiveness of alpha-ionol to male solanaceous fruit flies. Cade oil is produced by destructive distillation of Juniperus oxycedrus twigs and, as such, contains a large number of compounds (over 200). Through a process of preparation of chemical fractions of cade oil and subsequent bioassays in an outdoor olfactometer with sexually mature solanaceous fruit flies, seven compounds present within cade oil were found to potentially provide some level of synergistic enhancement of the attraction of alpha-ionol to male solanaceous fruit flies. In a preliminary field trial using sterile sexually mature flies, four of these compounds (eugenol, isoeugenol, dihydroeugenol, and 4-ethyl-2-methoxyphenol) showed relatively greater synergistic attractiveness than the other three compounds. These results improve our understanding of the male attractant for the solanaceous fruit fly and can help in the development of an improved male attractant for this fruit fly species.
Technical Abstract: Cade oil, destructive distillation tar of Juniperus oxycedrus twigs, is known to enhance attractancy of alpha-ionol for male solanaceous fruit fly (Bactrocera latifrons). Cade oil was extracted with NaOH aqueous solution and hexane, and these extracts were then fractionated chromatographically. Bioactivities of each fraction were tested with sexually mature B. latifrons in an outdoor olfactometer, and chemicals were analyzed by gas chromatography-mass spectrometry (GC-MS). Approximately 220 chemicals were found in the hexane and base extracts. Profile comparison of GC-MS chromatograms and bioactivities between fractions indicated seven chemicals as active components in cade oil to enhance the attractancy of alpha-ionol. These chemicals are 4-allyl-2-methoxyphenol (eugenol), 2-methoxy-4-propenylphenol (isoeugenol), 2-allyl-6-methoxyphenol (o-eugenol), 2-methoxy-4-propylphenol (dihydroeugenol), 3-hydroxy-4-methoxybenzaldehyde (isovanilin), 2-butenal (crotonaldehyde), and 4-ethyl-2-methoxyphenol. Bioassays in the outdoor olfactometer and preliminary field trials of the authentic chemicals showed that eugenol, isoeugenol, dihydroeugenol, and 4-ethyl-2-methoxyphenol showed relatively greater synergistic attractiveness than the other three compounds.