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Electroantennogram (EAG) evaluation of selected compounds from wilted leaves of black poplar, Populus nigra, showed that phenyl acetaldehyde, methyl salicylate, (E)-2-hexenal elicited strong responses from male antennae of Helicoverpa armigera. When mixed with sex pheromone (Ph), some volatiles, e.g. phenyl acetaldehyde, benzyl alcohol, phenylethanol, methylsalicylate, linalool, benzaldehyde, (Z)-3-hexenol, (Z)-3-hexenylacetate, (Z)-6-nonenol, cineole, (E)-2-hexenal, and geraniol elicited stronger responses from male antennae than Ph alone. Wind tunnel bioassay demonstrated that various volatiles could either enhance or inhibit the effect of synthetic sex pheromone. (E)-2-hexenal, (Z)-3-hexenol and linalool in combination with Ph could not induce any male to land on source at all, whereas phenyl acetaldehyde, benzaldehyde, (Z)-6-nonenol and salicylaldehyde combined with Ph enhanced male response rates by 58.63%, 50.33%, 51.85% and 127.78%, respectively, compared to Ph alone. These results suggested that some volatiles should modify sex pheromone caused behavior and that some of them could possibly be used as a tool for disrupting mating or for enhancing the effect of synthetic sex pheromone in the field.

The rice stem borer, Chilo suppressalis (Walker), and the rice leaf folder, Cnaphalocrocis medinalis Guenée, are two of the most destructive lepidopteran pests in rice. Since these two pyralid insects overlap in their occurrence in rice paddy fields, farmers prefer to set their pheromone-baited traps together in the rice fields for their monitoring. However, our field observation demonstrated that no male adult of C. suppressalis was captured in traps baited with commercial sex pheromone of C. suppressalis (CCS) combined with commercial sex pheromone of C. medinalis (CCM). To confirm that the C. medinalis sex pheromone component(s) interfere with the attraction of males of the rice stem borers to their conspecific females, single components of C. medinalis sex pheromone combined with CCS in traps were tested in the laboratory and rice paddy field. The results revealed that the two alcohol components in CCM, i.e. (Z)-11-octadecen-1-ol (Z11-18: OH) and (Z)-13-octadecen-1-ol (Z13-18: OH) may cause a significant reduction in capturing C. suppressalis males caused by CCS. We recommend against using these sex pheromones together in the field and suggest that Z11-18: OH and Z13-18: OH could be potential inhibitors or antagonists of C. suppressalis sex pheromone to control the rice stem borer. [ABSTRACT FROM AUTHOR]

Pheromonal communication is important in insect mate finding and reproduction. Identifying components of pest insect pheromone system is a first step to disrupt pest insect reproduction. In this study, we identified and cloned the pheromone biosynthesis activating neuropeptide receptor (PBANR) from the Asian corn borer, Ostrinia furnacalis (Guenée) (Lepidoptera: Pyralidae), which is one of the most damaging pests of corn and other crops in parts of Asia and Australia. The O. furnacalis PBANR (OstfuPBANR) gene has an ORF of 1,086 bp and encoded 362 amino acids with seven transmembrane domains and had a high sequence identity to known lepidopteran PBANRs. Expression analysis showed that OstfuPBANR was highly expressed in the pheromone glands compared with other tissues, consistent with other studies. Interestingly, OstfuPBANR was expressed higher in the larval stages compared to the pupal or adult stages, suggesting that OstfuPBANR may have broad functions in larva beyond adult pheromone synthesis. [ABSTRACT FROM AUTHOR]