Robert A. Flath

Host-plant green-leaf volatiles synergize the synthetic sex pheromones of the corn earworm and codling moth (Lepidoptera).

SummaryThe 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 certainH. zea hosts, (Z)-3-hexenyl acetate, not only significantly increased the capture ofH. zea males but were preferred over traps baited only with sex pheromone. Similarly, traps baited with synthetic sex pheromome ofC. 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.

Eight 1,4-naphthoquinones from Juglans

Abstract Eight volatile 1,4-naphthoquinones from acetone extracts of unripe black walnut (Juglans nigra) and English walnut (Juglans regia) fruit were identified by gas chromatography-mass spectrometry assisted by 1H NMR. Compounds not previously reported in walnut are 2-methyl-1,4-naphthoquinone, 2,3-dihydro-5-hydroxy-2-methyl-1,4-naphthalenedione (β-hydroplumbagin), 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin), 5-hydroxy-3-methyl-1,4-naphthoquinone and 2,3-dimethyl-5-hydroxy-1,4-naphthoquinone. The latter two compounds are here first reported as natural products.

The identification of volatile compounds in human urine

Abstract Since we are using the gas chromatography of volatile urine constituents in a procedure to diagnose diseases, we wished to identify the components of our sample. Forty-two compounds were identified by gas chromatography—mass spectroscopy, using a modified head-space collection technique. A co-injection procedure was used to place these components on a chromatogram from our disease diagnosis instrument.

Attractants fromStaphylococcus aureus cultures for Mexican fruit fly,Anastrepha ludens

Volatile chemicals from tryptic soy broth cultures ofStaphylococcus aureus that attract sugar-fed, protein-hungry adult Mexican fruit flies were identified. Chemicals identified from the headspace above the filtrate of the bacterial cultures were ammonia, trimethylamine, isoamylamine, 2-methylbutylamine, 2,5-dimethylpyrazine, and acetic acid. Each chemical attracted flies. A mixture of the chemicals in the same concentrations as were found in the bacterial filtrate was 89% as effective in attracting flies as the bacterial filtrate in laboratory bioassays. Additional chemicals were identified from various concentrated or pH altered preparations made from the filtrate. Many of these chemicals also attracted flies. One of these chemicals, dimethylamine, was the most effective chemical identified. The use of solid-phase microextraction for volatile collection and of thick-film (5-µm) capillary GC columns was essential to the success of this work.

A four-component attractant for the mexican fruit fly,Anastrepha ludens (Diptera: Tephritidae), from host fruit.

Sixteen chemicals found in fermented chapote fruit odor were evaluated as attractants for hungry adult Mexican fruit flies. Ethyl octanoate, ethyl benzoate, terpinyl acetate, ethyl salicylate, and (−)-α-copaene proved slightly attractive. Several of the chemicals also were tested for their ability to increase the attractiveness of the previously developed chapote-derived attractant (CEH) consisting of 1,8-cineole, ethyl hexanoate, and hexanol. Combinations containing CEH with ethyl octanoate, ethyl benzoate, 4-terpineol, (−)-α-cubebene, orα-terpineol were significantly more attractive than CEH alone. The two most attractive four-component combinations were ethyl octanoate with CEH (CEHO) and ethyl benzoate with CEH. No combinations containing greater numbers of chemicals were significantly more attractive than CEHO. Therefore, CEHO was selected for further study in this paper. Of CEHO component ratios that were tested, the most attractive was 10∶1∶1∶100 for the chemicals 1,8-cineole, ethyl hexanoate, hexanol, and ethyl octanoate, respectively. Formulations of CEHO into rubber septa and polyvinyl chloride (PVC) were aged 0–15 days and tested againstTorula yeast in competing McPhail traps in a flight chamber. Summed over all lure ages, rubber septa and PVC dispensers, respectively, were 1.2 and 1.5 times more attractive thanTorula yeast. PVC dispensers aged 10–15 days were approximately 2.1 times more attractive thanTorula yeast.

Volatiles from grapes. Comparison of grenache juice and grenache rose wine.

n a continuing effort to elucidate volatile organic material in grapes and grape products, we have extended our I work to comparing the volatiles from grenache grapes and the wine (rose) produced from the same batch of juice. The volatile constituents of the grenache juice have been reported (Stevens et a!., 1967); however, the constituents in the wine and juice from the same source have not been compared. Webb (1967) lists five classifications of flavor compounds found in wines. The first consists of compounds produced by the plant, which come through the processing unchanged. Numbers two through five consist of compounds produced during fermentation and aging. An analysis of the must and wine should prove helpful in distinguishing which components in the wine are from the raw material. This type of investigation does not differentiate between classifications two through five.

COYOTE ESTROUS URINE VOLATILES

Samples of female coyote urine were taken once or twice each week during the winter and spring for two years. Headspace analysis was employed with Tenax GC trapping and GC-MS. Tenax trapping was started in less than 1 hr after sampling, and mild conditions were used to minimize losses of highly volatile and labile compounds. Thirty-four compounds were identified. They include sulfur compounds, aldehydes and ketones, hydrocarbons, and one alcohol. The principal constituent is methyl 3-methylbut-3-enyl sulfide, which usually comprised 50% or more of the total volatiles observed. The concentration of many constituents varied widely. This appeared to be quasiperiodic for five of the constituents, with a period of a few weeks, and with pronounced maxima at the peak of estrus. Apparently these compounds are 3-methyltetrahydrothiophene, methyl 3-methylbutyl sulfide, octanal, dodecanal, and bis(3-methylbut-3-enyl) disulfide. One or more of these compounds may have pheromonal activity in coyote relationships.

Some volatile constituents of female dog urine

The volatile compounds from female beagle urine, across the state of estrus, were examined by headspace gas chromatography and mass spectrometry. The major constituents identified were methyl propyl sulfide, methyl butyl sulfide, and acetone. Nine minor constituents, including trimethyl amine and five disulfides, were identified. Two of the unidentified minor constituents may possibly be associated with the state of estrus.

(Z)-oxacyclotridec-10-en-2-one, an alfalfa weevil feeding deterrent from Medicago rugosa

Abstract ( Z )-Oxacyclotridec-10-en-2-one, a constituent ofa steam volatile fraction from Medicago rugosa leaves and stems, inhibits adult alfalfa weevil feeding on an inert substrate, and may be responsible for the strong resistance to weevil feeding exhibited by this annual Medicago species.

Microcell for Nuclear Magnetic Resonance Analyses

The use of a commercially available all-glass spherical sample-chamber microcell in combination with a time-averaging computer for nuclear magnetic resonance (NMR) analyses of microsamples has recently been reported. Brame has described a technique for trapping small gas-chromatographically isolated samples directly in such an all-glass NMR microcell. A somewhat different, easily fabricated microcell has been constructed and tested in our laboratories with excellent results. The design is a modification of a cell first described by Frei and Niklaus.