Progress 10/01/99 to 09/30/04
Outputs
Dr. Bowers has retired from the University of Arizona.
Impacts
The development of methods to induce plants to protect themselves without the use of toxic chemicals reveals an environmentally protective method to control both insect and nematode crop pests.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
These investigations seek to discover novel phytochemistry that will interfere with insect growth, developmental and behavioral processes. We have discovered that we can induce certain crop plants to increase their titer of phytoecdysones to levels lethal to insects by mechanical damage and/or by treatment with certain plant wound hormones. We have also determined that the induction of these hormones are also effective nematode pests.
Impacts
The development of methods to induce plants to protect themselves without the use of toxic chemicals reveals an environmentally protective method to control both insect and nematode crop pests.
Publications
- Schmelz, E. A., Grebenok R. J. Ohnmeiss,T. E. & Bowers. W. S. 2002. Interactions Between Spinacia oleracea and Bradysia impatiens: A Role for Phytoecdysteroids. Arch. Ins. Biochem. & Physiol. 51:204-221.
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Progress 01/01/00 to 12/31/00
Outputs
This project seeks to discover among the defensive chemistry of plants novel leads for the development of environmentally benign insecticides, fungicides and antibiotics for plant and animal protection. From an Asian tree (Eucalyptus maculata citriodon) commonly used for the preparation of insect repellents we isolated the principal active component and identified it as citronellal. This identification was important to resolve reports by others that have identified repellent compounds of different chemistry in steam distillates of the same tree. We conclude from our work that the repellent chemicals identified by others from this tree result from chemical changes caused by the distillation process itself and are not normal constituents present in the intact tree.Seeking novel leads for new insecticides and behavior modifying chemistry we have identified the defensive chemistry of the insect Pachycoris stallii Uhler (Heteroptera:Scutelleridae) as well as volatile
chemicals produced by its host plant Croton californicus Muell.-Aug. (Euphorbiaceae).
Impacts
This project seeks to discover among the defensive chemistry of plants and insects novel leads for the development of environmentally benign repellents, insecticides, fungicides and antibiotics for plant and animal protection. The resource to these studies are the indigenous plants from the Middle East and Asia.
Publications
- 1.Russell, G. B., W. S. Bowers, V. Kessing, H. M. Niemeyer, T. Sevenet, S. Vasanthayerni, & S. D. Wratten. 2000. Patterns of bioactivity and herbivory on Nothofagus species from Chile and new Zealand. J. Chemical Ecology, 26, No. 1, 41-56.
- 2.Bowers, W. S., P. H. Evans & P. Spence. 2000. Trichomes of Eucalyptus maculata citriodon possess a single potent insect repellent. Jour. Herbs, Spices & Medicinal Plants. 7,(4) 85-89.
- 3.Schmelz, E. A., R. J. Grebenok, T. E. Ohnmeiss & W. S. Bowers. 2000. Phytoecdysteroid turnover in spinach: Long-term stability supports a plant defense hypothesis. J. Chemical Ecology Vol.26, No. 12, p 2883-2896.
- 4.Williams, L., P. E. Evans & W. S. Bowers. 2001. Defensive chemistry of an aposematic bug, Pachycoris stallii Uhler (Heteroptera: Scutelleridae), and volatile compounds of its host plant Croton californicus Muell.-Arg. (Euphorbiaceae). J. Chem. Ecol. 27(2) 203-216. 5.Becerra, J. X., D. L. Venable, P. H. Evans & W. S. Bowers. 2001. Interactions between chemical and mechanical defenses in the plant genus Bursera and their implications for herbivores. American Zoologist, in press.
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Progress 01/01/99 to 12/31/99
Outputs
This project seeks to discover among the defensive chemistry of plants novel leads for the development of environmentally benign insecticides, fungicides and antibiotics for plant and animal protection. The resource to these studies are the indigenous plants from the Middle East and Asia which have long been used in traditional medicine. These studies have already revealed new chemistry for several insecticides and two potent insect repellents from Australian and New Zealand flora. We have also been able to protect plants from insect attack by inducing them to mobilize and deploy their defensive chemistry with systemic acquired resistance inducers.
Impacts
This project seeks to discover among the defensive chemistry of plants novel leads for the development of environmentally benign insecticides, fungicides and antibiotics for plant and animal protection. The resource to these studies are the indigenous plants from the Middle East and Asia We have also been able to protect plants from insect attack by inducing them to mobilize and deploy their defensive chemistry with systemic acquired resistance inducers.
Publications
- Schmelz, E. A., R. J. Grebenok, D. W. Galbraith, W. S. Bowers. 1999. Insect induced synthesis of phytoecdysteroids in spinach (Spinacia oleracea). J. Chemical Ecology. Journal of Chemical Ecology 25, No. 8, 1739-1757
- Russell, G. B., W. S. Bowers, V. Keesing, H. M. Niemeyer, T. Sevenet, S. Vasanthaverni & S. D. Wratten. 2000. Patterns of bioactivity and herbivory on Nothofagus species from Chile and New Zealand. J. Chemical Ecology 26, No. 1
- Evans, P. H., W. S. Bowers, M. Litaudan & T. Sevenet. 1999. Plumbagin from Diospyros olen. Molecules 4, M93.
- Bowers, W. S., P. H. Evans & P. Spence. 2000. Trichomes of Eucalyptus maculata citriodon possess a single potent insect repellent. Jour. Herbs, Spices & Medicinal Plantes accepted for publication.
- Evans, P.H., J. X. Becerra, D. L. Venable and W. S. Bowers. 2000. Chemical Analysis of the Squirt-Gun Defense in Bursera and the Counterdefense by Chrysomelid Beetles Journal of Chemical Ecology, Volume 26, No. 1
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Progress 01/01/98 to 12/31/98
Outputs
This study evaluates medicinal plants of indigenous origin from the Middle East and Asia for insecticides, insect growth regulators, fungicides and antibiotics. We have found several insecticides and antibiotics which we are isolating an characterizing. We identified the glandular secretion of an Australian tree that is powerfully repellent to insects. The trichome contains a single compound, citronellal, which changes with time into an even more powerful repellent. We are investigating the chemistry of the changes. We are also examining ways to induce plants to produce their repellent and antifeedant secretions as a possible new and natural method for plant protection.
Impacts
(N/A)
Publications
- Anderson, J. F., J. K. Walding, P. H. Evans, W. S. Bowers, & R. Feyereisen. 1997. Substrate specificity for the epoxidation of terpenoids and active site topology of house fly cytochrome P450 6A1. Chemical Research in Toxicology 10, 156-164.
- Jurberg, J., C. Galvao, W. S. Bowers, E. S. Garcia & P. Azambuja. 1997. Biomorphological alterations induced by an anti-juvenile hormonal compound, 1-(2-ethoxyethoxy)ethyl furfuryl ether, on three species of triatominae larvae (Hemiptera, Reduviidae). Memorias Do Instituto Oswaldo Cruz, 92: 2, 263-268.
- Bowers, W. S. 1997. Phytochemical defenses targeting the insect endocrine system. Acta Botanica Gallica, 144 (4), 391-400.
- Bowers, W. S. 1997. Phytochemical defenses targeting insect behavior. Acta Botanica Gallica, 144 (4), 383-390.
- Ortego, F. & W. S. Bowers. 1997. Biological activities of two juvenoids on nymphs of the American bird grasshoper Schistocerca americana (Drury). Insect Sci. Applic. 16 (3/4): 357-361.
- Schmelz, E. A., R. J. Grebenok, D. W. Galbraith, W. S. Bowers. 1998. Damage induced accumulation of phytoecdysteroids in spinach: A rapid root response involving the octadecanoid pathway. J. Chemical Ecology 24, No. 2, 339-360.
- Sutherland, T. K., G. C. Unnithan, J. F. Andersen, P. H. Evans, M. B. Murataliev, L. Z. Szabo, E. A. Mash, W. S. Bowers & R. Feyereisen. 1998. A cytochrome P450 terpenoid hydroxylase linked to the suppression of insect juvenile hormone synthesis. Proc. U. S. Natl. Acad. Sci. 86, 5997-6001.
- Sener, B. F. Bingol, I, Erdogan, W. S. Bowers, P. H. Evans. 1998. Biological activities of some Turkish medicinal plants. Pure & Applied Chemistry 70: (2) 403-406.
- Schmelz, E. A. & W. S. Bowers. 1998. Induction of 20-hydroxyecdysone in spinach (Spinacia oleracea) Proc. 6th Australasian Applied Entomological Research Conference. 1: 390-399.
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Progress 01/01/97 to 12/31/97
Outputs
We are exploring the secondary chemistry of plants used medicinally in cultures of the Middle East (Turkey, Egypt) for compounds with biological activity against insects pests and pathogens. We have isolated and identified antibiotics of unusual chemistry that are effective against several agricultural pathogens. We have also discovered plants with hormonal and antihormonal activity against insects and are studying how insects induce their production in plants. We are particularly interested in the salivary contents of insects that serve as inducers of plant defensive chemistry including repellents and antifeedants. We suspect that effective inducers of systemic acquired resistance might be used to stimulate plant resistance against insect herbivory offering a novel method of plant protection with consequent reduction in the use of synthetic toxicants. One student is associated with this work.
Impacts
(N/A)
Publications
- Bowers, W. S. 1996. Botanical Mosquito Repellents. The IPM Practitioner, 18, No. 8, 13..
- Ortego, F., P. H. Evans & W. S. Bowers. 1997. Enteric and Plant Derived Deterrents in the Regurgitate of the American Bird Grasshopper, Schistocerca americana (Drury). Jour. of Chemical Ecology. 23, 1941-50.
- Bowers, W. S., B. Sener, P. H. Evans, F. Bingol & I. Erdogan. 1997. Activity of Turkish Medicinal Plants against Aedes aegypti and Anopheles gambiae. Insect Science and its Application, 16, (3/4) 339-342.
- Anderson, J. F., J. K. Walding, P. H. Evans, W. S. Bowers, & R. Feyereisen. 1997. Substrate specificity for the epoxidation of terpenoids and active site topology of house fly cytochrome P450 6A1. Chemical Research in Toxicology 10, 156-164.
- Jurberg, J., C. Galvao, W. S. Bowers, E. S. Garcia & P. Azambuja. 1997. Biomorphological alterations induced by an anti-juvenile hormonal compound, 1-(2-ethoxyethoxy)ethyl furfuryl ether, on three species of triatominae larvae (Hemiptera, Reduviidae). Memorias Do Instituto Oswaldo Cruz, 92, Iss 2, 263-268.
- Bowers, W. S. 1997. Phytochemical defenses targeting the insect endocrine system. Acta Botanica Gallica, 144 (4), 391-400.
- Bowers, W. S. 1997. Phytochemical defenses targeting insect behavior. Acta Botanica Gallica, 144 (4), 383-390.156.
- Chung, Bu Keun & W. S. Bowers. 1997. Synergism of several synergists of antijuvenile hormone analog, 7-ethoxy precocene II in the milkweed bug, Oncopeltus fasciatus Dallas, submitted.
- Ortego, F. & W. S. Bowers. 1997. Biological activities of selected juvenoids on nymphs of the American bird grasshoper Schistocerca americana (Drury). Insect Science and its Application. (Orthoptera:Acrididae)Accepted for publication Dallas. Accepted for publication.
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Progress 01/01/96 to 12/30/96
Outputs
Investigation of the organosoluble extracts of several plants, used for medicinal purposes in the Middle East, revealed species from eight plant families with significant insecticidal activity. Of special interest was their insecticidal activity against the mosquitoes Aedes aegypti and Anopheles gambiae. Exposure of second instar larvae to the plant extracts in water gave high mortality. A. gambiae was found to be the most sentitive to the crude extracts giving complete mortality within 24 hours at dosages as low as 7 micrograms per milliliter of water. Bioassay guided isolation of the active constituents is underway. We found that the enteric fluids of the American Bird grasshoppers, Schistocerca americana (Drury) fed on wheat seedlings possess powerful deterrent activity against insects including ants in the genus Crematogaster. Investigation of aqueous extracts of wheat seedlings also yielded deterrent fractions identical with those from the insect suggesting that
the deterrent regurgitate of grasshoppers is composed of natural products present in the food plants. Bioassay guided isolation of the active deterrents is being undertaken. Endocrinological studies revealed that the ecdysone antagonist RH-5849 induced autotomy in the American Bird grasshopper Schistocerca americana (Drury) probably by disruption of the nerve potassium channel.
Impacts
(N/A)
Publications
- ORTEGO, F., P.H. EVANS & W.S. BOWERS. 1997. Enteric and plant derived deterrentsin the regurgitate of the American Bird grasshopper, Schistocerca americana (Drury). Jour. Chem. Ecology. In Press.
- BOWERS, W.S., B. SENER, P.H. EVANS, F. BINGOL & I. ERDOGAN. 1997. Activity of Turkish medicinal plants against Aedes aegypti and Anopheles gambiae. Insect Science and Its' Application. In Press.
- ORTEGO, F. & W.S. BOWERS. 1996. Induction of autotomy in the American Bird grasshopper Schistocerca americana (Drury) by the ecdysone agonist RH-5849 and investigation of its mode of action. Experientia 52:42-50.
- HONDA, H. & W.S. BOWERS. 1996. Feeding and oviposition deterrent activities of flower buds of globe mallow, Sphaeralcea emoryi Torrey, against boll weevil Anthonomus grandis Boheman (Coleoptera: Curculionidae). J. Chem. Ecology, 22: No. 1, 1 student associated with this work.
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Progress 01/01/95 to 12/30/95
Outputs
NATURAL PRODUCT CHEMISTRY ......... Cris. rept. 96) From fifty-five medicinal plants we discovered sixteen extracts lethal to brine shrimp, twenty-six toxic to insects, seventeen with antimicrobial activity against bacteria and fungi and nine were nematocidal. Although there was some crossover activity among the arthropods (ie., insects and brine shrimp) several extracts showed activity specific to pests or pathogens suggesting that the results are not due to non-specific, indifferent toxicants. Isolation and characterization of the active compounds is continuing.
Impacts
(N/A)
Publications
- Russell, G. B., M. B., Hunt, W. S. Bowers & J. W. Blunt. 1994. A sesquiterpenoid ant repellent from Dysoxylum spectabile. Phytochemistry 35, 1455-1456.
- Bowers, W. S., Unnithan, G. P., Fukushima, J., Toda, J., & Sugiyama, T. 1995. Synthesis and biological activity of furanyl anti-juvenile hormonal compounds. Pesticide Science 43 : (1) 1-12.
- Bowers, W. S., P. H. Evans & J. Martini. 1995. Chemical-Ecological Investigations as a Resource to the Discovery of Environmentally Pacific methods for Insect Pest Management. In "1st. International Conference on Contemporary Pest Control P
- Bowers, W. S. 1995. Antijuvenile hormones: Prospective growth regulators. In "Recent Advances in Insect Biochemistry and Molecular Biology. (Ed.) S. Y. Takahashi. Nagoya Univ. Press, pp191-204.
- Bowers, W. S., B. Sener, P. H. Evans, F. Bingol & I. Erdogan. 1996. Biological Activities of Turkish Medicinal Plants Against Agricultural and Public Health Pests. Planta Medica, (In press) Azambuja, P., Garcia, E. S. & W. S. Bowers. 19
- Bowers, W. S. 1996. Phytochemical defenses targeting the insect endocrine system. Acta Botanica Gallica, Bull. Soc. Botan. Fr. (accepted)
- Bowers, W. S. 1996. Phytochemical defenses targeting insect behavior. Acta Botanica Gallica, Bull. Soc. Botan. Fr. (accepted).
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