Field response of the pine sawflyNeodiprion sertifer to controlled release of diprionyl acetate, diprionyl propionate andtrans-perillenal

Sex Pheromone of the Introduced Pine Sawfly, Diprion similis, Revisited to Define a Useful Monitoring Lure: Deviating Chiral Composition and Behavioural Responses Compared to Earlier Reports

Extracts of Diprion similis females contained about 15 ng of the sex pheromone precursor 3,7-dimethylpentadecan-2-ol per female. After derivatisation with (S)-2-acetoxypropanoyl chloride, we found that the major stereoisomer in the extract was (2S,3R,7R)-3,7-dimethylpentadecan-2-ol. Small amounts of other stereoisomers of 3,7-dimethylpentadecan-2-ol were also identified in the extract, namely 1% of (2R,3S,7S), 0.3% (2R,3R,7R) and 0.4% of (2R,3R,7S). An unknown fifth substance showed a very similar spectrum to 3,7-dimethylpentadecan-2-ol, both in SIM and full scan mode. None of the earlier suggested behavioural synergistic isomers ((2S,3S,7S), (2S,3S,7R) and (2S,3R,7S)) were detected in the extracts. In field tests in Ontario, Canada, the earlier identified main pheromone component, viz. the propanoate of (2S,3R,7R)-3,7-dimethylpentadecan-2-ol, was tested alone and in combination with other stereoisomers, earlier reported to be synergistic. No synergistic effects were detected and the threo four-isomer blend was as attractive as the pure main compound. Thus, one of the few examples of a diprionid sawfly using more than one substance in its sex pheromone could not be confirmed. The results also suggest that monitoring programs can use the more easily synthesized threo-blend without losing efficiency. Furthermore, the study suggests that other diprionid pheromones may benefit from a reinvestigation, to clarify possible synergistic effects of stereoisomers.

Sex pheromone of the pine false webworm Acantholyda erythrocephala

Females of the pine false webworm Acantholyda erythrocephala (L) produce the sex pheromone (Z)-6, 14-pentadecadienal, which attracts flying males in the field. By using gas chromatography coupled with electroantennographic detection (GC-EAD) and mass spectrometry (GC-MS), we detected (Z)-6,14-pentadecadienal in volatile collections and in whole body extracts of female A. erythrocephala. Females, but not males, also exhibited a 25-carbon cuticular hydrocarbon, (Z,Z)-1,9,15-pentacosatriene, which can oxidize to (Z)-6,14-pentadecadienal upon exposure to air and sunlight. (Z,Z)-1,9,15-Pentacosatriene and (Z)-6,14-pentadecadienal identifications were corroborated by comparison with synthetic standards. (Z)-6, 14-Pentadecadienal is the second pheromone identified for pamphilliid sawflies, and the first to elicit strong field attraction, and thus offer potential as a pheromone lure to aid in control of this forest pest.

Field response of male pine sawflies, Neodiprion sertifer (Diprionidae), to sex pheromone analogs in Japan and Sweden

The pine sawfly Neodiprion sertifer (Geoffroy) uses the acetate or propionate of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol) as pheromone components, with the (2S,3R,7R)-isomer being antagonistic, synergistic, or inactive according to the population tested. In this study, we tested the attraction of males to the acetates of three analogs of diprionol, each missing one methyl group, viz. (2S,7S)-7-methyl-2-pentadecanol, (2S,6S)-2,6-dimethyl-1-tetradecanol, and (2S,3S)-3-methyl-2-pentadecanol. None of the analogs alone, or in combination with diprionol acetate, was attractive in Sweden, even at 100 times the amount of diprionol acetate attractive to N. sertifer. In Japan, the acetate of (2S,3S)-3-methyl-2-pentadecanol attracted males when tested in amounts 10-20 times higher than the acetate pheromone component. The acetate esters of the (2S,3R)-analog and the (2S,3R,7R)-isomer of diprionol also were tested in combination with the pheromone compound (acetate ester). Both compounds caused an almost total trap-catch reduction in Sweden, whereas in Japan they appear to have relatively little effect on trap capture when added to diprionol acetate. Butyrate and iso-butyrate esters of diprionol were unattractive to N. sertifer in Sweden. In summary, there exists geographic variation in N. sertifer in responses to both diprionyl acetate and some of its analogs.

Sex pheromone of the pine sawfly, Gilpinia pallida: chemical identification, synthesis, and biological activity

We present the identification of the sex pheromone in the pine sawfly, Gilpinia pallida, including analysis of the female pheromone content, male antennal response and attraction in the field, and synthesis of the most active pheromone component. Several 3,7-dimethyl-2-alkanols were identified from female whole-body extracts, including some compounds with a 2R configuration. This is the first observation of such compounds in a pine sawfly species. Antennae of male G. pallida responded strongly in electroantennograph (EAG) recordings to the (2S,3R,7R)-isomers of the propionates of 3,7-dimethyl-2-tridecanol, 3,7-dimethyl-2-tetradecanol, and 3,7-dimethyl-2-pentadecanol, as well as to the acetates of the tri- and pentadecanols (the acetate of the tetradecanol was not tested). The propionate of (2S,3R,7R)-3,7-dimethyl-2-tetradecanol caught more males in the field than the corresponding isomer of tri- or pentadecanol. We suggest that the (2S,3R,7R)-isomer of 3,7-dimethyl-2-tetradecanol is likely the main sex pheromone precursor in G. pallida, with a subsidiary role for the (2S,3R,7R)-isomer of the tridecanol. Preparation of highly pure (2R,3R,7R)- and (2S,3R,7R)-stereoisomers of 3,7-dimethyl-2-tetradecanol, including the biological active esters, was performed via chemoenzymatic methods and is described in detail.

Capture rates of the European pine sawfly, Neodiprion sertifer, in pheromone traps, with special regard to effects of wind speed

Males of the European pine sawfly, Neodiprion sertifer Geoffr., were marked and released downwind from pheromone traps, baited with 100 micrograms of the sex pheromone (2S,3S,7S)-3,7-dimethyl-2-pentadecyl acetate. Males were released 5 m downwind from one trap, or downwind from five traps, 50 m or 200 m away. The average capture rates after 24 hr were 21.5%, 17.7% and 3.8%, respectively. The capture rate was highest at moderate wind speeds (1-2 m/sec) in the 50 m experiments, whereas it decreased above wind speeds of 1.5 m/sec in the 200 m experiments. With no precipitation and > 13.5 degrees C during overcast, wind speed is presumably the most important climatic factor for N. sertifer males flying upwind to a pheromone source. Travel time, the elapsed time form take-off to landing on the trap, varied considerably, and the shortest recorded travel times were 1, 6 and 45 min for the 5, 50, and 200 m experiments, respectively. The trap efficiency i.e., number of captured males per number of males that landed on the trap, was estimated at 52% in the 5 m experiments. The sampling range after 24 hr was calculated at approximately 400 m by regression analysis. The combination of the males' flight ability during upwind progress and their longevity (12 days), suggests a potentially large seasonal sampling range of the traps used in this study.

Release rates for pine sawfly pheromones from two types of dispensers and phenology of Neodiprion sertifer

Comparisons of release rates, duration in the field, and catch efficiency of polyethylene and cotton roll dispensers for the sex pheromones of sawflies (Hymenoptera: Diprionidae) were conducted. The release rates of the Neodiprion sertifer (Geoffr.) and Diprion pini (L.) sex pheromones, the acetates of pentadecanol and (2S,3S,7S)-3,7-dimethyl (2S,3R,7R)-3,7-dimethyl-2-tridecanol from polyethylene dispensers were measured at different temperatures in the laboratory. The release rates for the substances depended on both the temperature and initial load in the vials. The catch from cotton rolls baited with 100 micrograms of the acetate or propionate of 3,7-dimethyl-2-pentadecanol was compared to the catch from regularly renewed cotton rolls baited with 10 micrograms of the same acetate. The catch was higher for the 100-microgram cotton rolls for, at most, 45 days, and there was no significant differences in catch between the acetate and the propionate. The catch in traps baited with polyethylene or cotton roll dispensers loaded with the acetate of 3,7-dimethyl-2-pentadecanol was compared and showed that cotton roll traps mirrored the decreasing release of the substance rather than the actual flight activity. The length of the flight period of N. sertifer in Sweden, the Czech Republic, Italy, and Greece did not exceed 100 days in any of the countries. By adjusting the initial pheromone load of the polyethylene vials to the expected temperatures, it should be possible to get a constant and sufficiently high release rate during the entire flight period.