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Commercial Delicious apple essence was extracted to yield an oil with a strong apple-like aroma.This oil was separated into its components with high-resolution packed and opentubular gas chromatographic columns. Fiftysix compounds were identified, mainly by a combination of mass spectrometry and gas-chromatographic retention data. While many of these compounds contribute to over-all Delicious apple essence aroma, the main components directly associated with characteristic apple-like aroma were ethyl 2-methylbutyrate, hexanal, and 2-hexenal.

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A method developed for the quantitative analysis of tomato volatiles has been extended to cover the

Fifty-six compounds from the odor of 'calling', sexually mature, laboratory reared males of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritida~) were isolated by headspace trapping on Tenax columns and identified using GC/MS techniques (69 total compounds were detected). Electroantennogram responses (EAGs) to 54 of the 56 identified compounds as well as 5 analogs were tested on both sexes. Significant differences between the sexes in their responsiveness were found in 9 of the 54 identified compounds tested. There was no correlation between the amplitude of the EAG response and the relative abundance of compound identified from headspace analysis. Of the five 'major' identified components, three elicited relatively small EAG responses, while two elicited large EAGs compared to the hexan-l-ol standard. The relative ranking of EAG responses were: methyl and ethyl hexenoates and hexanoates > C4 -C6 esters and/or acetates > ethyl and methyl octenoates > monoterpenes > sesquiterpenes > C2-C5 acetates, alcohols and ketones. Behavioral bioassays on each of the five 'major' identified components as well as a blend of six of the compounds showed some degree of attractancy to virgin females which in some cases approached the response to a 'pheromonal' standard (male odors absorbed onto filter paper). These results are discussed in relationship to the insect's antennal sensitivity to putative 'pheromone' components and/or allomonal components and to other reported C. capitata pheromone studies.

Summary. The capture of adult male moths in female sex pheromone traps of two key agricultural pests, the corn earworm (Helicoverpa zea) and the codling moth (Cydia pomonella), is enhanced or synergized by a certain group of host-plant volatiles, the "green-leaf volatiles" (GLVs). Since female adults of both species call and release their sex pheromones while perched upon the leaves of their host-plants, the volatile constituents from the leaves of a number of host-plants were compared. Sex pheromone traps containing one of the prominent leaf volatiles of certain H. zea hosts, (Z)-3-hexenyl acetate, not only significantly increased the capture of H. zea males but were preferred over traps baited only with sex pheromone. Similarly, traps baited with synthetic sex pheromome of C. pomonella plus a blend of GLVs captured significantly more males than traps baited only with sex pheromone. Since male moths are not captured in traps baited only with these GLVs, it appears that these GLVs act as pheromone synergists which increase or enhance the attraction or arrestment of male moths in pheromone traps.

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