Showing papers by "Jocelyn G. Millar published in 1992"

Identification of oviposition attractants for Culex quinquefasciatus from fermented Bermuda grass infusions.

Abstract: Compounds which attract and stimulate oviposition by gravid Culex quinquefasciatus were isolated and identified from a fermented Bermuda grass infusion. The neutral portion of the ether extract of the aqueous infusion contained the stimulatory materials. Fractionation by liquid chromatography yielded an active fraction containing phenol, 4-methylphenol, 4-ethylphenol, indole and 3-methylindole. A blend of the 5 compounds strongly stimulated oviposition, as did blends of any 4 of them. Bioassays with individual compounds showed that only 3-methylindole consistently induced oviposition, in concentrations spanning 5 orders of magnitude.

Codling Moth (Lepidoptera: Tortricidae) Control by Dissemination of Synthetic Female Sex Pheromone

Abstract: Permeation of a synthetic pheromone mixture through an isolated Asian pear orchard provided excellent control of the codling moth in the Sacramento Valley of California during a 2-yr period. The synthetic pheromone mixture was applied in 1,050 plastic twist-tie dispensers and at the rate of 100 g codlemone, 50 g dodecanol, and 10 g of tetradecanol per hectare. Female codling moth antennae give electroantennogram responses to these compounds.

Behavioral and electrophysiological activity of (Z,E)-7,9,11-dodecatrienyl formate, a mimic of the major sex pheromone component of carob moth,Ectomyelois ceratoniae.

Abstract: The behavioral and electrophysiological activity of a mimic [(Z,E)7,9,11-dodecatrienyl formate] of the major sex pheromone component [(Z,E) 9,11,13-tetradecatrienal] of carob moth was assessed. Wind-tunnel bioassays demonstrated that the formate was as effective as natural gland extracts, and significantly more effective than the trienal alone or than the trienal blended with two minor pheromone components, in evoking source contact. Dispensers containing the formate were as effective as trienal-containing blend lures in attracting males when placed at the same dosage in traps in date gardens. Single-cell recordings showed that at least two olfactory neurons, differentiated by spike amplitude, are located in the long trichoid hairs on male carob moth antennae. Dose-response relationships indicated that puffs from cartridges loaded with at least 0.1 μg of the formate or of the trienal were necessary to elicit spiking by either the small or the large-spiking cell within a sensillum. Cross-adaptation studies demonstrated that both compounds stimulated the same large-spiking cell. The frequencies of spikes evoked from the large cell when stimulated by emissions from 0.1-μg, 1-μg, or 10-μg cartridges of either the formate or the trienal were not significantly different, suggesting that the formate is an effective mimic of the trienal at the antennal receptor cell level.

Seasonal patterns and pesticidal effects on the phototoxic linear furanocoumarins in celery, Apium graveolens L

Abstract: Seasonal trends and pesticidal effects on the phototoxic linear furanocoumarins in petioles and leaves of celery (Apium graveolens L.) were documented. Total linear furanocoumarins in petioles from untreated plants (range = 0.34-1.1.84,microgram/g of fresh weight) did not reach levels known to cause contact dermatitis in either 1989 or 1990. In leaf samples, total linear furanocoumarin concentrations in untreated plants at harvest (1989, 2.95 microgram/g; 1990, 5.90 microgram/g) were low but exceeded levels known to produce dermatitis for at least 6 weeks in 1990 (maximum = 15.85 microgram/gram). Similar concentrations were recorded only once in 1989 (11.52 microgram/g). Bergapten showed the highest seasonal and weekly concentrations in leaves and petioles during both years, followed by xanthotoxin and then psoralen. The concentration of bergapten in petioles declined significantly as plants matured. Concentrations of furanocoumarins in the leaves did not correlate with concentrations in the petioles in either year. In general, pesticides had relatively little effect on linear furanocoumarin induction.

Resistance to Spodoptera exigua in Apium prostratum

Abstract: Two Apium accessions were compared with the commercial cultivar ‘Tall Utah’ 52–70R (A. graveolens [L.]) for resistance to Spodoptera exigua (Hubner)(Lepidoptera: Noctuidae). Oviposition rate was not significantly different between the three genotypes. In all accessions, eggs were usually placed on the upper half of the plants. Implications of this oviposition pattern on S. exigua management in celery are discussed. The wild species A. prostratum ssp prostratum var filiform (A230) showed a significantly higher resistance to S. exigua than 52–70R. The levels of carcinogenic and mutagenic linear furanocoumarins in the commercial cultivar 52–70R (1.41 μg/g in the petioles; 5.85 μg/g in the leaves) and in the plant accession A. nodiflorum (5.40 μg/g in the petioles; 2.99 μg/g in the leaves) were far below the concentration reported to produce acute contact dermatitis (18.0 μg/g). The levels of furanocoumarins in A. prostratum petioles (186.14 μg/g) and leaves (326.45 μg/g) were 10 and 18 times higher, respectively, than the concentration known to cause contact dermatitis. However, resistance in A. prostratum was primarily due to non-preference and the linear furanocoumarins did not induce non-preference. Therefore, the resistance shown by this plant accession does not appear to be furanocoumarin-based and may be suitable for transfer to commercial celery for use in S. exigua management.

An equilibrium and stability study of Δ(1)-pyrroline.

Abstract: Several properties of the compound 3,4-dihydro-2H-pyrrole(A1-pyrroline), which has been reported as a component of the male-produced Mediterranean fruit fly pheromone, have been determined by [1H]- and [13C]nuclear magnetic resonance spectroscopy. The stability of Δ1-pyrroline in several solvents and at moderately elevated temperatures has been investigated, and it has been established that it exists as both a monomer and trimer in solution. Although equilibrium studies indicate that the trimer is thermodynamically more stable than the monomer in solution, only the monomer was found in the vapor phase based on infrared analysis.

Reexamination of the Female Sex Pheromone of the Peach Twig Borer: Field Screening of Minor Constituents of Pheromone Gland Extracts and of Pheromone Analogs

Abstract: Several minor constituents in extracts of female peach twig borer, Anarsia lineatella Zeller, pheromone glands have been identified as decyl acetate, ( E )- and (Z)-4- decenyl acetate, and ( E, E )3,5- and (Z, E)3,5-decadienyl acetate. Decyl acetate and (E)-4- decenyl acetate were also identified in effiuvia from live female moths. None of the identified compounds enhanced the attractiveness of the standard blend of (E)-5-decenol and (E)-5-decenyl acetate (19:81) in field tests. However, the analogous compounds ( E )-6- decenyl acetate and (E)-7-decenyl acetate were identified as behavioral antagonists, and strongly suppressed trap captures. When the contents of various commercial pheromone lures and mating disruption devices were analyzed, one batch of lures that performed very poorly in field tests was found to contain the inhibitory compound (E)-6-decenyl acetate.

Sex pheromone components of the geometrid moths Lobophora nivigerata and Epirrhoe sperryi

Abstract: 3Z,6Z,9Z-Nonadecatriene (3Z,6Z,9Z-19:H; other abbreviations follow the same pattern) has been identified as a female sex pheromone component of the geometrid mothEpirrhoe sperryi (H.). 3Z,6Z,9Z-18:H and 6Z,9Z-19:H were also identified in pheromone gland extracts but had no apparent biological activity. 3Z,6Z,9Z-21:H was tentatively identified as a female sex pheromone component of a second geometrid species,Lobophora nivigerata (Wlk.). Attraction of male moths to this compound was strongly synergized by the addition of small amounts of 6Z,9Z-21:H to lures.

Control of the straw itch mite (Acari: Pyemotidae) with sulfur in an insect rearing facility.

Abstract: The ectoparasitic mite Pyemotes tritici (Lagreze-Fossat & Montane) (Acari: Pyemotidae) caused paralysis and reduced longevity in eucalyptus longhorned borer, Phoracantha semipunctata F., under laboratory rearing conditions. Application of dusting sulfur to logs that contained pupating borers greatly reduced densities of mites on emerging adult beetles and increased beetle survivorship. Uniform application to all logs in a glasshouse effectively eradicated the mite infestation. A bioassay showed that sulfur may physically impede the dispersal of immature mites by adhering to the cuticle, but sulfur vapor did not act as a toxin.