Almond seed wasp (Hymenoptera: Eurytomidae) sex pheromone: effect of trap type, trap position, blend ratio and time of the day on male attraction.

Field trials were carried out in order to evaluate some of the factors affecting male response of the almond seed wasp, Eurytoma amygdali Enderlein, to traps baited with the alkadienes (Z,Z)-6,9-tricosadiene and (Z,Z)-6,9-pentacosadiene, the male attractant of this species. The trials were conducted in Latomia, Microthivae, Kanalia and Sykourion (Thessaly, Central Greece) during the 2004 growing season. In all regions, captures in traps baited with a 7:3 ratio of the above blend significantly and positively correlated with male emergence from infested almonds that had been placed in cages in the experimental fields. Traps baited with the 7:3 pheromone ratio were significantly more effective in capturing males than traps baited with the 1:1 ratio, supporting the hypothesis that (Z,Z)-6,9-tricosadiene is the main component of this attractant. Of four trap types tested, Rebel and Lasiotraps attracted significantly more males than Delta and Funnel traps. Height had no effect on trap efficiency; however, males were captured earlier in the day in traps placed 2.3 m above grown than in traps placed 1.3 m above grown. Most male activity was recorded between 10 and 12 h, but captures were continuously recorded during the entire monitoring interval from 6 to 17 h.

Insecticidal activity of Citrus aurantium fruit, leaf, and shoot extracts against adult olive fruit flies (Diptera: Tephritidae).

Solvent extracts of differing polarity from Citrus aurantium (L.) (Rutaceae) fruit, leaves, and shoots were evaluated for biological activity against adults of the olive fruit fly, Bactrocera oleae (Gmelin) (Diptera: Tephritidae). Using a petri dish residual exposure bioassay, we found that the petroleum ether extract from fruit alone showed insecticidal activity against the flies. The extract of the three fruit tissues (flavedo [peel], albedo, and flesh) indicated that bioactivity was limited to the flavedo, and this activity was significantly higher than that of the whole fruit extract. The most effective extract was obtained when fresh flavedo was used, whereas extracts of oven-dried flavedo were inactive. Fruit maturity also affected bioactivity; extracts of ripe fruit were more effective than those of unripe fruit. Our results suggest that C. aurantium flavedo contains secondary metabolites with insecticidal activity against B. oleae adults.

Partial purification and insecticidal activity of toxic metabolites secreted by a Mucor hiemalis strain (SMU-21) against adults of Bactrocera oleae and Ceratitis capitata (Diptera: Tephritidae).

The secondary metabolites present in the methanol extract of a Mucor hiemalis strain (SMU-21) mycelia, cultured in liquid medium, were evaluated for toxicity to Bactrocera oleae (Gmelin) and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) adults. Feeding and contact bioassays revealed that the methanol fraction of the crude supernatant was strongly toxic to both species. Symptoms of toxicity developed quickly; lethargy occurred 1-2 h posttreatment, and mortality reached 82-97% after 24 h. Both feeding and contact bioassays showed that B. oleae was more susceptible than C. capitata. Concentrations producing 50% mortality (LC50) to B. oleae and C. capitata after 24 h in feeding bioassays were 0.52 and 1.28 mg/ 0.1 ml diet, respectively, but 34.8 and 64.0 microg/ cm2, respectively, after 4 h in contact bioassays. Solvent partition, precipitation, and chromatographic procedures were used to isolate the active principles from the crude supernatant. These resulted in the isolation of one high-pressure liquid chromatography fraction with insecticidal activity on B. oleae flies equal to the initial crude supernatant.

Microflora species and their volatile compounds affecting development of an alcohol dehydrogenase homozygous strain (Adh-I) of Bactrocera (Dacus) oleae (Diptera: Tephritidae).

Microflora species and volatiles emitted from artificial diets were examined from the larvae of three homozygous alcohol dehydrogenase (Adh) strains of the olive fruit fly, Bactrocera (Dacus) oleae (Gmelin), reared under identical conditions. Differences in volatile composition were detected when Adh-I homozygous larvae developed in a diet lacking the preservative p-hydroxybenzoic acid methyl ester (nipagin). Larval development of the Adh-I strain in the preservative-free diet was reduced by 50%, whereas pupal emergence was completely inhibited. The larval development and pupal emergence of Adh-F and Adh-S strains were not affected. Unique microorganisms with characteristic volatile profiles were isolated from the preservative-free diet of the Adh-I strain that were different from those, isolated from Adh-S, Adh-F, laboratory colony, and wild insect populations. Our results indicated that the variations in volatile composition of the artificial diets, and the inhibition of larval development and pupal emergence in Adh-I strain were related to changes in the microflora that developed in the diets of the Adh-I strain.

Chemical composition of corn leaf essential oils and their role in the oviposition behavior of Sesamia nonagrioides females.

The chemical composition of the volatile oils collected by steam distillation from leaves of seven corn hybrids and their effect on the oviposition behavior of Sesamia nonagrioides females was studied. Samples of the volatile oils from each of the hybrids were analyzed by capillary gas chromatography-mass spectrometry (GC-MS) and several major compounds were identified. The major compound found in all seven hybrids was 3,7,11,15-tetramethyl-2-hexadecen-1-ol (phytol), ranging from 38.3 to 64.9% of the total quantity. Compounds detected in significant proportions include (Z)-3-hexenol (3.1 to 8%), nonanal (4.9 to 14.5%), pentadecanal (1.8 to 5.8%), neophytadiene (5.5 to 12.9%), (Z)-3-hexenyl acetate (2.5 to 8.9%), and an analogue of 2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3-(4H)-one (DIMBOA) (2.4 to 9.3%). The analysis showed no qualitative differences among the chemicals identified while quantitative differences were detected. Among the volatile oils, the significant difference was in the quantity of aldehydes present. In two-choice bioassays, filter paper sticks treated with volatile oils containing higher quantity of aldehydes received fewer eggs than those with lower aldehyde quantity. Bioassays with synthetic aldehydes of a chain length C9-C14 confirmed the above results.

Alkadienes and alkenes, sex pheromone components of the almond seed wasp Eurytoma amygdali.

Whole body extracts of virgin Eurytoma amygdali females were attractive to males in laboratory bioassays. Extracts of various body parts of the female wasp elicited different responses to males, with the thorax extract being the most active. Preparative fractionation of the crude hydrocarbon extract on a silver nitrate impregnated silica gel column (alkanes, alkenes, and alkadienes) revealed that the highest male response was elicited by alkadienes and the lowest by alkenes, with the alkane fraction being inactive. The identification of alkenes and alkadienes was based on gas chromatographic, mass spectrometric, and gas-phase infrared data. Laboratory bioassays suggested that the two alkadienes, (Z,Z)-6,9-tricosadiene [(Z,Z)-6,9-C23:2], and (Z,Z)-6,9-pentacosadiene [(Z,Z)-6,9-C25:2], and to a lesser extent alkenes, identified in the female extract of E. amygdali were male attractants.

Female sex pheromone components of jasmine mothPalpita unionalis (Lepidoptera: Pyralidae).

(E)-11-Hexadecenal and (E)-11-hexadecen-1-yl acetate were found in abdomen tip extracts from females of the jasmine mothPalpita unionalis (Hübn). The identification was based on capillary GC analyses, mass spectrometry, and laboratory and field tests. In laboratory bioassays, both components elicited a low level of upwind flight by males. The two components when tested separately in the field were inactive, but the blend of the two components at a ratio of (3:7) was highly attractive to males. Traps baited with 1 mg of the two-component blend were competitive to traps baited with five virgin females. The addition of Z isomers components reduced male capture.

Sex pheromone components of corn stalk borerSesamia nonagriodes (Lef.) isolation, identification, and field tests.

Z-11-Hexadecenyl acetate (Z11-16∶OAc), dodecyl acetate (12∶OAc),Z-11-hexadecenal (Z11-16∶Aid), andZ-11-hexadecenol (Z11- 16∶OH), were found in pheromone gland extracts of femaleSesamia nonagriodes (Lef.) [Lepidoptera: Noctuidae]. These four components were also present in airborne volatiles collected from calling virgin females in a 65∶18∶8∶9 ratio. Hexadecyl acetate (16∶OAc) was also detected but found to be inactive. The identification was based on multicolumn GC analysis, mass spectrometry, and field activity.Z11-16∶OAc is the major sex pheromone component; the addition of the secondary components individually decreased male captures. The blend of the four synthetic components in 69∶15∶8∶8 ratio was highly attractive to males; 200 µg per trap was the most effective concentration in field tests.

Male olive fruit fly attraction to synthetic sex pheromone components in laboratory and field tests.

Male olive fruit fly attraction to the four synthetic components of the female sex attractant pheromone was studied under laboratory and field conditions. In laboratory tests males responded to all four components tested separately. Component I, (1,7-dioxaspiro[5.5]undecane) was more attractive than any of the remaining three components alone, but a combination of all four was more attractive than component I alone. In field tests with polyethylene vials as pheromone dispensers, the complete mixture, although not statistically significant, was constantly more attractive to males than component I alone. A tendency of enhancement of attraction of component I by combining it with component II (α-pinene) or III (n-nonanal) was also observed. In field tests with rubber septa as pheromone dispensers only component I was attractive. Mixtures containing component I were also attractive but not more attractive than component I alone. Evaporation rate and ratio of components as they come out of the dispenser appear to be critical for male response.

A multicomponent female sex pheromone ofDacus oleae Gmelin: Isolation and bioassay.

The sex attractant pheromone produced by femaleDacus oleae Gmelin is a mixture of four compounds, two of which are found in the rectal gland and the other two elsewhere in the insect body. The ratio of these compounds in the pheromone blend was measured. Biological activity of all four compounds and their combinations was studied in lab and field cage tests. The most abundant compound in the mixture (55.7%) shows the highest biological activity. Recombination of all compounds significantly increases activity of the main compound.