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Arne E. Sauer - One of the best experts on this subject based on the ideXlab platform.

  • Variables Affecting Pheromone Concentration in Vineyards Treated for Mating Disruption of Grape Vine Moth Lobesia botrana
    Journal of Chemical Ecology, 1998
    Co-Authors: Arne E. Sauer, Gerhard Karg
    Abstract:

    Airborne Pheromone Concentration in a field is one of the most important variables for the successful application of mating disruption in pest control. In the present paper, we estimated the Pheromone Concentration with field EAG recordings in vineyards and investigated parameters affecting Concentration. Pheromone Concentration showed a positive correlation with number of dispensers per hectare (= number of point sources). A twofold increase in the absolute number of dispensers per hectare with a constant number of point sources (two dispensers at the same location) did not significantly affect relative Pheromone Concentration. Measurements carried out in plots where dispensers had been applied at different heights showed highest relative Pheromone Concentrations in plots with dispensers at 0.1 m and 1.4 m above the ground. Those Concentrations were not significantly different from each other, but were significantly higher than in plots where dispensers had been placed at a height of 2 m. Foliage of grape vines substantially affected the development of high Pheromone Concentrations. In summer, in vineyards with fully developed leaf canopy, significantly higher Pheromone Concentrations could be measured shortly after application of the dispensers compared to vineyards in spring with sparse vegetation. The decline of Pheromone Concentrations after removal of dispensers is significantly prolonged in full vegetation, showing the impact of plant canopy on Pheromone Concentrations. In contrast, ground cover between the grapevine rows did not significantly affect mean Pheromone Concentrations.

  • Seasonal Variation of Pheromone Concentration in Mating Disruption Trials Against European Grape Vine Moth Lobesia botrana (Lepidoptera: Tortricidae) Measured by EAG
    Journal of Chemical Ecology, 1997
    Co-Authors: Gerhard Karg, Arne E. Sauer
    Abstract:

    Spatial and temporal distributions and relative Concentrations of the Pheromone of the European grape vine moth Lobesia botrana (Lepidoptera: Tortricidae) were measured in mating disruption trials with electroantennograms. Measurements were carried out over several years during the flight season of the two generations of this pest insect. In three consecutive years significantly higher mean relative Pheromone Concentrations were measured in summer during the flight of the second generation of L. botrana than in spring during the flight of the first generation (P 0.05), but were significantly lower than those of a nearby intact vineyard (P < 0.001). The results provided additional evidence that foliage is an important parameter determining mean Pheromone Concentrations and temporal and spatial distribution of Pheromone in mating disruption trials.

  • Spatial distribution of Pheromone in vineyards treated for mating disruption of the grape vine mothLobesia botrana measured with electroantennograms.
    Journal of chemical ecology, 1995
    Co-Authors: Gerhard Karg, Arne E. Sauer
    Abstract:

    The spatial distribution of the Pheromone of the grape vine moth.Lobesia botrana (Lepidoptera: Tortricidae), was measured in vineyards treated for mating disruption by using an electroantennogram technique (EAG). Five hundred dispensers per hectare, each containing 0.1 g of the main component of the sex Pheromone (E,Z)-7,9-dodecadienyl acetate (E7,Z9-12: Ac) were evenly distributed in the experimental vineyards. The EAG amplitudes measured in the experimental plots were transformed into relative Pheromone Concentrations by means of a calibration curve. Mean relative Pheromone Concentrations in the center of a treated plot reached 2.31 × 10−4 relative units. No significant differences in the mean relative Pheromone Concentrations were found between replicate plots (P > 0.01). The mean relative Pheromone Concentrations measured within one plot along a transect at 5-m intervals also showed no significant differences between the sites. These results indicate that inside the borders of treated areas the Pheromone was evenly distributed. No sites with significantly lower Pheromone Concentrations, frequently assumed to be the cause for higher trap catches in some areas, were found. However, the mean relative Pheromone Concentration rapidly declined more than 100-fold outside the border of the treated plot. At 10 m from the treated area, the EAGs showed no significant difference compared to the EAGs recorded in an untreated area. A rapid drop in the mean relative Pheromone Concentration was also found on a vertical transect through the canopy of the vineyard. Measurements in an untreated control block gave a mean antennal response approximately 1000-fold lower than in a nearby Pheromone treated plot. The significance of the variation in the Pheromone distribution for the success of the mating-disruption method is discussed.

Gerhard Karg - One of the best experts on this subject based on the ideXlab platform.

  • Variables Affecting Pheromone Concentration in Vineyards Treated for Mating Disruption of Grape Vine Moth Lobesia botrana
    Journal of Chemical Ecology, 1998
    Co-Authors: Arne E. Sauer, Gerhard Karg
    Abstract:

    Airborne Pheromone Concentration in a field is one of the most important variables for the successful application of mating disruption in pest control. In the present paper, we estimated the Pheromone Concentration with field EAG recordings in vineyards and investigated parameters affecting Concentration. Pheromone Concentration showed a positive correlation with number of dispensers per hectare (= number of point sources). A twofold increase in the absolute number of dispensers per hectare with a constant number of point sources (two dispensers at the same location) did not significantly affect relative Pheromone Concentration. Measurements carried out in plots where dispensers had been applied at different heights showed highest relative Pheromone Concentrations in plots with dispensers at 0.1 m and 1.4 m above the ground. Those Concentrations were not significantly different from each other, but were significantly higher than in plots where dispensers had been placed at a height of 2 m. Foliage of grape vines substantially affected the development of high Pheromone Concentrations. In summer, in vineyards with fully developed leaf canopy, significantly higher Pheromone Concentrations could be measured shortly after application of the dispensers compared to vineyards in spring with sparse vegetation. The decline of Pheromone Concentrations after removal of dispensers is significantly prolonged in full vegetation, showing the impact of plant canopy on Pheromone Concentrations. In contrast, ground cover between the grapevine rows did not significantly affect mean Pheromone Concentrations.

  • Seasonal Variation of Pheromone Concentration in Mating Disruption Trials Against European Grape Vine Moth Lobesia botrana (Lepidoptera: Tortricidae) Measured by EAG
    Journal of Chemical Ecology, 1997
    Co-Authors: Gerhard Karg, Arne E. Sauer
    Abstract:

    Spatial and temporal distributions and relative Concentrations of the Pheromone of the European grape vine moth Lobesia botrana (Lepidoptera: Tortricidae) were measured in mating disruption trials with electroantennograms. Measurements were carried out over several years during the flight season of the two generations of this pest insect. In three consecutive years significantly higher mean relative Pheromone Concentrations were measured in summer during the flight of the second generation of L. botrana than in spring during the flight of the first generation (P 0.05), but were significantly lower than those of a nearby intact vineyard (P < 0.001). The results provided additional evidence that foliage is an important parameter determining mean Pheromone Concentrations and temporal and spatial distribution of Pheromone in mating disruption trials.

  • Spatial distribution of Pheromone in vineyards treated for mating disruption of the grape vine mothLobesia botrana measured with electroantennograms.
    Journal of chemical ecology, 1995
    Co-Authors: Gerhard Karg, Arne E. Sauer
    Abstract:

    The spatial distribution of the Pheromone of the grape vine moth.Lobesia botrana (Lepidoptera: Tortricidae), was measured in vineyards treated for mating disruption by using an electroantennogram technique (EAG). Five hundred dispensers per hectare, each containing 0.1 g of the main component of the sex Pheromone (E,Z)-7,9-dodecadienyl acetate (E7,Z9-12: Ac) were evenly distributed in the experimental vineyards. The EAG amplitudes measured in the experimental plots were transformed into relative Pheromone Concentrations by means of a calibration curve. Mean relative Pheromone Concentrations in the center of a treated plot reached 2.31 × 10−4 relative units. No significant differences in the mean relative Pheromone Concentrations were found between replicate plots (P > 0.01). The mean relative Pheromone Concentrations measured within one plot along a transect at 5-m intervals also showed no significant differences between the sites. These results indicate that inside the borders of treated areas the Pheromone was evenly distributed. No sites with significantly lower Pheromone Concentrations, frequently assumed to be the cause for higher trap catches in some areas, were found. However, the mean relative Pheromone Concentration rapidly declined more than 100-fold outside the border of the treated plot. At 10 m from the treated area, the EAGs showed no significant difference compared to the EAGs recorded in an untreated area. A rapid drop in the mean relative Pheromone Concentration was also found on a vertical transect through the canopy of the vineyard. Measurements in an untreated control block gave a mean antennal response approximately 1000-fold lower than in a nearby Pheromone treated plot. The significance of the variation in the Pheromone distribution for the success of the mating-disruption method is discussed.

G. Karg - One of the best experts on this subject based on the ideXlab platform.

  • Predicting Atmospheric Concentration of Pheromone in Treated Apple Orchards
    Journal of Chemical Ecology, 1999
    Co-Authors: David M. Suckling, S R Green, A R Gibb, G. Karg
    Abstract:

    A Lagrangian model was developed to predict the vertical distribution of Pheromone in apple orchards treated with synthetic Pheromone released from polyethylene tubing dispensers. Measurements of tree dimensions' dispenser heights, air temperature, and wind speed were used as inputs to the model. Data to test the model output were obtained by air sampling and capillary gas chromatography to determine atmospheric Pheromone Concentration. The model predicted highest Concentrations of Pheromone in the plane of the dispensers. Predicted and measured Concentrations were in the range 0.5–5 ng/m3 for blocks treated with 1000 or 2000 dispensers/ha. Mean wind speed had a large influence on Pheromone Concentrations within the canopy with Concentrations decreasing at higher wind speeds. Wind speeds

  • predicting atmospheric Concentration of Pheromone in treated apple orchards
    Journal of Chemical Ecology, 1999
    Co-Authors: D M Suckling, S R Green, A R Gibb, G. Karg
    Abstract:

    A Lagrangian model was developed to predict the vertical distribution of Pheromone in apple orchards treated with synthetic Pheromone released from polyethylene tubing dispensers. Measurements of tree dimensions' dispenser heights, air temperature, and wind speed were used as inputs to the model. Data to test the model output were obtained by air sampling and capillary gas chromatography to determine atmospheric Pheromone Concentration. The model predicted highest Concentrations of Pheromone in the plane of the dispensers. Predicted and measured Concentrations were in the range 0.5–5 ng/m3 for blocks treated with 1000 or 2000 dispensers/ha. Mean wind speed had a large influence on Pheromone Concentrations within the canopy with Concentrations decreasing at higher wind speeds. Wind speeds <0.1 m/sec, which represent good flying conditions for moths, resulted in high levels of mean Pheromone Concentration. Dispenser height had only a small influence on the maximum Pheromone Concentration, with the peak Concentrations decreasing with increasing application height. The lower peak Concentration for an elevated dispenser occurred mainly because wind speeds were higher in the upper parts of the tree canopy. Air temperature, dispenser density, and Pheromone release rate (as inferred by dispenser liquid length), also had a significant influence on Pheromone Concentration because of the linear relationship between these parameters and the corresponding flux of Pheromone released into the treated orchards. We use known scaling relationships to demonstrate these effects.

  • Polyethylene dispensers generate large-scale temporal fluctuations in Pheromone Concentration
    Environmental Entomology, 1997
    Co-Authors: G. Karg, David M. Suckling
    Abstract:

    The temporal distribution of Pheromone of Epiphyas postvittana (Walker) and its possible effect on communication disruption was investigated using field electroantennogram (EAG) measurements and insect traps. Three replicate matched pairs of blocks were Pheromone-treated with 700 dispensers per hectare or left as untreated controls. An array of 9 delta traps was installed in the center of each block. Male catch in the traps baited with rubber septa containing Pheromone was recorded daily, and the following weekly cycle was operated: disruptant Pheromone dispensers were present in the field for 2 d, but were then removed from treated plots for 5 d. Significant disruption of trap catch occurred for the 2 d that dispensers were present, and for 1 additional night following their removal. Field EAG recordings of 3 min duration taken while the dispensers were present showed a high frequency of large pulses as fluctuations in Pheromone Concentration in the treated area. No comparable pulses were measured in the untreated control blocks or from 5 min to 1 h after the removal of the dispensers from the treated area. The frequency of the Pheromone pulses in treated plots was positively correlated with wind speed. After removal of the dispensers from the treated plots, die mean EAG signal declined linearly, indicating a log-linear rate of drop in mean Pheromone Concentration. Our results show that the large fluctuations in Pheromone Concentration detected in EAG recordings arise from the dispensers. However, large fluctuations detectable by EAG do not seem to be required for mating disruption of E. postvittana .

A R Gibb - One of the best experts on this subject based on the ideXlab platform.

  • predicting atmospheric Concentration of Pheromone in treated apple orchards
    Journal of Chemical Ecology, 1999
    Co-Authors: D M Suckling, S R Green, A R Gibb, G. Karg
    Abstract:

    A Lagrangian model was developed to predict the vertical distribution of Pheromone in apple orchards treated with synthetic Pheromone released from polyethylene tubing dispensers. Measurements of tree dimensions' dispenser heights, air temperature, and wind speed were used as inputs to the model. Data to test the model output were obtained by air sampling and capillary gas chromatography to determine atmospheric Pheromone Concentration. The model predicted highest Concentrations of Pheromone in the plane of the dispensers. Predicted and measured Concentrations were in the range 0.5–5 ng/m3 for blocks treated with 1000 or 2000 dispensers/ha. Mean wind speed had a large influence on Pheromone Concentrations within the canopy with Concentrations decreasing at higher wind speeds. Wind speeds <0.1 m/sec, which represent good flying conditions for moths, resulted in high levels of mean Pheromone Concentration. Dispenser height had only a small influence on the maximum Pheromone Concentration, with the peak Concentrations decreasing with increasing application height. The lower peak Concentration for an elevated dispenser occurred mainly because wind speeds were higher in the upper parts of the tree canopy. Air temperature, dispenser density, and Pheromone release rate (as inferred by dispenser liquid length), also had a significant influence on Pheromone Concentration because of the linear relationship between these parameters and the corresponding flux of Pheromone released into the treated orchards. We use known scaling relationships to demonstrate these effects.

  • Predicting Atmospheric Concentration of Pheromone in Treated Apple Orchards
    Journal of Chemical Ecology, 1999
    Co-Authors: David M. Suckling, S R Green, A R Gibb, G. Karg
    Abstract:

    A Lagrangian model was developed to predict the vertical distribution of Pheromone in apple orchards treated with synthetic Pheromone released from polyethylene tubing dispensers. Measurements of tree dimensions' dispenser heights, air temperature, and wind speed were used as inputs to the model. Data to test the model output were obtained by air sampling and capillary gas chromatography to determine atmospheric Pheromone Concentration. The model predicted highest Concentrations of Pheromone in the plane of the dispensers. Predicted and measured Concentrations were in the range 0.5–5 ng/m3 for blocks treated with 1000 or 2000 dispensers/ha. Mean wind speed had a large influence on Pheromone Concentrations within the canopy with Concentrations decreasing at higher wind speeds. Wind speeds

S R Green - One of the best experts on this subject based on the ideXlab platform.

  • predicting atmospheric Concentration of Pheromone in treated apple orchards
    Journal of Chemical Ecology, 1999
    Co-Authors: D M Suckling, S R Green, A R Gibb, G. Karg
    Abstract:

    A Lagrangian model was developed to predict the vertical distribution of Pheromone in apple orchards treated with synthetic Pheromone released from polyethylene tubing dispensers. Measurements of tree dimensions' dispenser heights, air temperature, and wind speed were used as inputs to the model. Data to test the model output were obtained by air sampling and capillary gas chromatography to determine atmospheric Pheromone Concentration. The model predicted highest Concentrations of Pheromone in the plane of the dispensers. Predicted and measured Concentrations were in the range 0.5–5 ng/m3 for blocks treated with 1000 or 2000 dispensers/ha. Mean wind speed had a large influence on Pheromone Concentrations within the canopy with Concentrations decreasing at higher wind speeds. Wind speeds <0.1 m/sec, which represent good flying conditions for moths, resulted in high levels of mean Pheromone Concentration. Dispenser height had only a small influence on the maximum Pheromone Concentration, with the peak Concentrations decreasing with increasing application height. The lower peak Concentration for an elevated dispenser occurred mainly because wind speeds were higher in the upper parts of the tree canopy. Air temperature, dispenser density, and Pheromone release rate (as inferred by dispenser liquid length), also had a significant influence on Pheromone Concentration because of the linear relationship between these parameters and the corresponding flux of Pheromone released into the treated orchards. We use known scaling relationships to demonstrate these effects.

  • Predicting Atmospheric Concentration of Pheromone in Treated Apple Orchards
    Journal of Chemical Ecology, 1999
    Co-Authors: David M. Suckling, S R Green, A R Gibb, G. Karg
    Abstract:

    A Lagrangian model was developed to predict the vertical distribution of Pheromone in apple orchards treated with synthetic Pheromone released from polyethylene tubing dispensers. Measurements of tree dimensions' dispenser heights, air temperature, and wind speed were used as inputs to the model. Data to test the model output were obtained by air sampling and capillary gas chromatography to determine atmospheric Pheromone Concentration. The model predicted highest Concentrations of Pheromone in the plane of the dispensers. Predicted and measured Concentrations were in the range 0.5–5 ng/m3 for blocks treated with 1000 or 2000 dispensers/ha. Mean wind speed had a large influence on Pheromone Concentrations within the canopy with Concentrations decreasing at higher wind speeds. Wind speeds