Showing papers by "Peter Witzgall published in 2008"

Codling Moth Management and Chemical Ecology

Abstract: Lepidopteran insects use sex pheromones to communicate for mating. Olfactory communication and mate-finding can be prevented by permeating the atmosphere with synthetic pheromone. Pheromonemediated mating disruption has become a commercially viable pest management technique and is used to control the codling moth, Cydia pomonella, a key insect pest of apple, on 160,000 ha worldwide. The codling moth sex pheromone, codlemone, is species specific and nontoxic. Orchard treatments with up to 100 grams of synthetic codlemone per hectare effectively control codling moth populations over the entire growing season. Practical implementation of the mating disruption technique has been realized at an opportune time, as codling moth has become resistant to many insecticides. We review codling moth chemical ecology and factors underlying the behavioral mechanisms and practical implementation of mating disruption. Area-wide programs are the result of collaborative efforts between academic research institutions, extension, chemical industries, and grower organizations, and they demonstrate the environmental and economic relevance of pheromone research.

Discrepancy in laboratory and field attraction of apple fruit moth Argyresthia conjugella to host plant volatiles

Abstract: Apple fruit moth Argyresthia conjugella is a specialist seed predator of rowan Sorbus aucuparia. Large-scale synchronous fluctuation of seed production in rowan (i.e. named masting) drives the apple fruit moth to seek alternative host plants such as apple, during years when rowan berries are not available for oviposition. The role of plant volatile compounds in the attraction of gravid apple fruit moth females is studied in a laboratory wind tunnel. Volatiles from rowan branches with green berries stimulate female moths to fly upwind and to land at the odour source. By contrast, females are not attracted to rowan branches without green berries, and they are not attracted to apple, demonstrating that the chemical stimulus from rowan berries is required for attraction. Attraction to synthetic compounds identified from rowan, anethole and 2-phenyl ethanol confirms the role of plant volatiles in host finding. These two compounds, however, show a discrepant behavioural effect in wind tunnel and field tests. Field traps baited with 2-phenyl ethanol capture female moths but anethole does not produce significant captures. Wind tunnel tests produce the opposite results: moths fly upwind towards the anethole lure, whereas 2-phenyl ethanol is not attractive at all. Wind tunnel attraction to 2-phenyl ethanol is achieved by adding odour from a rowan branch without berries, which is not attractive on its own. This finding demonstrates that interaction with the background odour contributes to the behavioural effect of plant volatile stimuli in the field.

Control de Tecia solanivora (Lepidoptera: Gelechiidae) mediante su feromona para la interrupción del apareamiento

Abstract: El objetivo del trabajo fue evaluar la tecnica de control de Tecia solanivora (Lepidoptera: Gelechiidae) por medio de la interrupcion del apareamiento para su posible factibilidad en el cultivo de la papa. En un tunel de viento una mezcla antagonica de la feromona constituida por E3-12Ac, Z3-12Ac y 12Ac en la proporcion 100:50:100, respectivamente (70 mg por dispensador) produjo una inhibicion total en la atraccion de machos hacia la feromona liberada por las hembras, en comparacion con hembras liberando la feromona (69% de atraccion). En campo esta mezcla a 10 hg/trampa inhibio significativamente la captura con dos machos/trampa, a diferencia de trampas control conteniendo E3-12Ac y Z3-12Ac (100:1 respectivamente) capturandose 50 machos/trampa. En 3 ha tratadas con la mezcla antagonica en dispensadores colocados en la base de plantas de papa a una densidad de 1.227 dispensadores/ha, (equivalente a 86 g de feromona/ha), se redujo significativamente la captura de machos en trampas para monitoreo en 94%, en 89% en trampas con hembras y la copula de parejas confinadas se redujo en 67%, en comparacion con un area testigo (1 ha sin tratar). Estos resultados indican el potencial de esta tecnica para reducir poblaciones de la plaga.

(Lepidoptera: Gelechiidae) mediante su feromona para la interrupción del apareamiento

Abstract: : The aim of this study was to evaluate the control of Tecia solanivora (Lepidoptera: Gelechiidae) through mating disruption for its possible feasibility in potato crops. In a wind tunnel, an unbalanced blend of the pheromone consisting of E3-12Ac, Z3-12Ac and 12Ac in the proportion 100:50:100, respectively (70 mg per dispenser), produced a total inhibition of male attraction to the pheromone released by females, as compared to females releasing the pheromone (69% attraction). In the field, this blend at 10 hg/trap significantly inhibited capture with two males/trap, whereas control traps containing E3-12Ac y Z3-12Ac (100:1 respectively) captured 50 males/trap. In 3 ha treated with the unbalanced blend in dispensers placed at the base of potato plants at a density of 1,227 dispensers/ha (equivalent to 86 g of pheromone/ ha), male attraction was significantly reduced to monitoring traps by 94%, by 89% to traps with females, and mating of confined pairs was reduced by 67%, in comparison with a control area (1 ha untreated). These results indicate the potential of this technique for reducing populations of the pest.

Control de Tecia solanivora (Lepidoptera: Gelechiidae) mediante su feromona para la interrupción del apareamiento Control of Tecia solanivora (Lepidoptera: Gelechiidae) through its pheromone for mating disruption

Abstract: The aim of this study was to evaluate the control of Tecia solanivora (Lepidoptera: Gelechiidae) through mating disruption for its possible feasibility in potato crops. In a wind tunnel, an unbalanced blend of the pheromone consisting of E3-12Ac, Z3-12Ac and 12Ac in the proportion 100:50:100, respectively (70 mg per dispenser), produced a total inhibition of male attraction to the pheromone released by females, as compared to females releasing the pheromone (69% attraction). In the field, this blend at 10 hg/trap significantly inhibited capture with two males/trap, whereas control traps containing E3-12Ac y Z3-12Ac (100:1 respectively) captured 50 males/trap. In 3 ha treated with the unbalanced blend in dispensers placed at the base of potato plants at a density of 1,227 dispensers/ha (equivalent to 86 g of pheromone/ ha), male attraction was significantly reduced to monitoring traps by 94%, by 89% to traps with females, and mating of confined pairs was reduced by 67%, in comparison with a control area (1 ha untreated). These results indicate the potential of this technique for reducing populations of the pest.