Progress 10/01/00 to 09/30/04
Outputs
Chemical ecology research has been highly productive, with a major emphasis on the behavioral activity of (Z)-3-hexenyl acetate. This compound is produced by wheat stem sawfly infested plants, as well as by uninfested plants. Wounding increases the amount of this volatile compound that is released by the plant. Ongoing field and laboratory research clearly suggests that wheat stem sawfly females lay more eggs in a variety that releases significantly higher amounts of (Z)-3-hexenyl acetate when compared to a variety that releases less. These results hold true in both green house and field experiments, and this promising avenue is being pursued from a trap crop perspective. Additionally, (Z)-3-hexenyl acetate plays an important role in enhancing the activity of pheromone lures used in traps to capture male and female wheat stem sawflies. Capture of both male and female sawflies are significantly enhanced when this compound is present along with a major pheromone
component. A field trial with these optimized lures is planned for the coiming field season.
Impacts
Optimized trap capture of wheat stem sawfly adults should provide a basis for semiochemically driven management of this pest. Additional research on host plant attraction is also very promising.
Publications
- Cosse, A.A., R.J. Bartelt, D.K. Weaver, and B.W. Zilkowski. 2002. Pheromone components of the wheat stem sawfly: Identification, electrophysiology, and field bioassay. J. Chem Ecol. 28: 391-407.
- Bartelt, R.J., A.A. Cosse, R.J. Petroski, and D.K. Weaver. 2002. Cuticular hydrocarbons and novel alkenediol diacetates from wheat stem sawfly (Cephus cinctus): Natural oxidation to pheromone components. J. Chem Ecol. 28: 369-390.
- Daisy, B. H., G. A. Strobel, U. Castillo, D. Ezra, J. Sears, D. K. Weaver, J. B. Runyon, and U. Castillo. 2002. Naphthalene, an insect repellent, is produced by Muscodor vitigenus, a novel endophytic fungus. Microbiology 148: 3737-3741.
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Progress 01/01/03 to 12/31/03
Outputs
This past year pheromone-baited trap tests indicated that earlier demonstration of enhanced capture of male and female sawflies by 9-acetyloxynonanal is facilitated by addition of a dominant host plant volatile. However, this past year we were able to demonstrate that a compound produced in higher amounts by females also enhanced male capture. Surprisingly, a dominant compound produced by both males and females was inhibitory to the overall capture caused by the plant compound and 9-acetyloxynonanal.
Impacts
Optimized trap capture of wheat stem sawfly adults should provide a basis for semiochemically driven management of this pest.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
Commonly grown spring wheat varieties from Montana produce: 3-hexenal, trans-2-hexenal, cis-3-hexenyl acetate, 6-methyl-5-heptan-2-one, trans-3-hexenyl acetate, 9-octadecanoic acid, trans-2-hexenyl acetate, 3-cyclohexenyl acetate and ocimene. Of these, cis-3-hexenyl acetate is much more abundant than the other compounds, but the amounts do vary quantitatively and qulaitatively. Soil type and light intensity also strongly influence the amount of material released. None of these compounds showed and behavioral activity for male adults sawwflies. Female sawflies were attracted to three compounds in at least one tested concentration. Of these attractive compounds, cis-3-hexenyl acetate was attractive at the concentration produced by wheat plants, whereas the other two compounds were attractive only at concentrations that were five times higher than the plants emitted. The known aphid repellant, 6-methyl-5-heptan-2-one is also repellant to ovipositing sawfly females, but
only at a concentration that is 100 fold gretaer than the plants emit. Cis-3-hexeynl acetate synergizes the capture of adult sawflies by 9-acetyloxynonanal, an identified wheat stem sawfly pheromone component.
Impacts
We hope to use information on plant volatiles to provide useful information to plant breeders and to make grower recommendations, as well as to directly manipulate the insects in applied trials. These compounds can be combined with pheromones to evaluate the potential for a semiochemical-based strategy for management.
Publications
- Runyon, J.B., W.L. Morrill, D.K. Weaver and P.R. Miller. 2002. Parasitism of the wheat stem sawfly (Hymenoptera: Cephidae) by Bracon cephi and Bracon lissogaster (Hymenoptera: Braconidae) in wheat fields bordering tilled and untilled fallow in Montana. J. Econ. Entomol. 95: 1130-1134.
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Progress 01/01/01 to 12/31/01
Outputs
Field trials of wheat stem sawfly pheromone blends were conducted. The experiments evaluated the performance of a five components blend relative to a single componenent previously shown to be attractive. The blend showed an enhanced capture rate due to improved trap design. Clear behavioral activity and lure potential for wheat stem sawfly adults has been demonstrated for certain host plant compounds. Lures are currently being developed.
Impacts
Improved lure and trap designs should greatly enhance our ability to evaluate the potential for semiochemical based management of the wheat stem sawfly.
Publications
- Cosse, A.A., R.J. Bartelt, D.K. Weaver, and B.W. Zilkowski. 2002. Pheromone components of the wheat stem sawfly: Identification, electrophysiology, and field bioassay. J. Chem Ecol. 28: 391-407.
- Bartelt, R.J., A.A. Cosse, R.J. Petroski, and D.K. Weaver. 2002. Cuticular hydrocarbons and novel alkenediol diacetates from wheat stem sawfly (Cephus cinctus): Natural oxidation to pheromone components. J. Chem Ecol. 28: 369-390.
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Progress 01/01/00 to 12/31/00
Outputs
Behavioral evidence was gathered for species isolation via pheromeone selectivity in two congeneric parasitoids attacking the wheat stem sawfly. Field trials of wheat stem sawfly pheromone blends were conducted. The experiments evaluated the performance of a five components blend relative to a single componenent previously shown to be attractive. The results showed no improvement over earlier performance. Trap design remains critical for this species. Additional behavioral data was collected to support the observation that wheat stem sawfly natural enemies target the hidden larvae using olfactory cues.
Impacts
Potential species-specific monitoring of wheat stem sawfly parasitoids will strongly support redistribution efforts. It is believed that certain local populations may be more effective than others, resulting in more rapidly establishing, efficient biological control. A trap that catches males of a particular species may be developed to accomplish this monitoring.
Publications
- No publications reported this period
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