Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-30T15:39:11.716Z Has data issue: false hasContentIssue false
  • English
  • Français

EFFECTIVENESS OF GALL INDUCERS IN WEED BIOLOGICAL CONTROL1

Published online by Cambridge University Press:  31 May 2012

P. Harris  and
J.D. Shorthouse
P. Harris*
Affiliation:
Research Centre, Agriculture and Agri-Food Canada, PO Box 3000, Lethbridge, Alberta, Canada T1J 4B1
J.D. Shorthouse
Affiliation:
Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6
*
2 Author to whom correspondence and reprint requests should be addressed.
Get access Rights & Permissions [Opens in a new window]

Abstract

Gall inducers are favoured as biocontrol agents of weeds because they tend to have a narrow host range. Six insect and one nematode gall inducer used in Canada are described in terms of their biology, gall morphology, gall physiology, and effectiveness in weed control. The species differ in plant organ attacked, requirement for moisture, whether the galls are induced by secretions or by severing xylem, and effectiveness, which in part relates to the ability of the gall to import nutrients. The most powerful galls divert assimilates from other sinks via a gall’s vascular system joined to that of their host. One of our examples also has mechanisms to compensate for reduction of turgor during drought. Two of the gall inducers enhance their nutrient supply by severing xylem in a plant nutrient sink. One, in the short-term sink of a thistle capitulum, obtains about a quarter of its assimilates at the expense of other capitula. The other, in the long-term sink of a rosette root, approximately halves seed production. Hypotheses are presented to explain various aspects of gall development and function.

Résumé

Les organismes gallicoles sont des agents de contrôle des mauvaises herbes particulièrement appréciés, car ils ont tendance à être spécifiques à un petit nombre d’hôtes. Nous avons étudié la biologie et l’efficacité de contrôle de six insectes et d’un nématode gallicoles utilisés dans la lutte contre les mauvaises herbes au Canada, de même que la morphologie et la physiologie des galles qu’ils génèrent. Les espèces n’attaquent pas toutes les mêmes organes sur les plantes, elles ne nécessitent pas toutes les mêmes conditions d’humidité, certaines déclenchent la formation de galles par l’émission de sécrétions, d’autres par rupture du xylème, et elles n’ont pas toutes la même efficacité contre les mauvaises herbes selon que les galles qu’elles provoquent peuvent ou non importer des éléments nutritifs. Les galles les plus efficaces s’approprient les métabolites destinés à d’autres sites via leur propre système vasculaire relié à celui de l’hôte. L’un des cas étudiés possède également des mécanismes de compensation de la perte de turgescence au cours des périodes de dessication. Deux des espèces gallicoles augmentent leurs réserves nutritives en court-circuitant le xylème de la plante. L’une, dans la zone d’utilisation à court terme des métabolites d’un capitule de chardon, obtient environ un quart de ses éléments nutritifs aux dépens des autres capitules. L’autre, dans la zone d’utilisation à long terme des métabolites d’une racine en rosette, réduit la production de graines d’environ la moitié. Des hypothesès sont avancées pour expliquer divers aspects de la formation et du rôle des galles.

[Traduit par la Rédaction]

Type
Articles
Information
The Canadian Entomologist , Volume 128 , Issue 6 , December 1996 , pp. 1021 - 1055
Copyright
Copyright © Entomological Society of Canada 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

1

Lethbridge Research Centre contribution No. 3879499.

References

Abe, Y. 1992. The advantage of attending ants and gall aggregation for the gall wasp Andricus symbioticos (Hymenoptera: Cynipidae). Oecologia 89: 166–167.CrossRefGoogle ScholarPubMed
Abrahamson, W.G., and McCrea, K.D.. 1986. Nutrient and biomass allocation in Solidago altissima: Effects of two stem gallmakers, fertilization, and ramet isolation. Oecologia 68: 174–180.CrossRefGoogle ScholarPubMed
Abrahamson, W.G., and Weis, A.E.. 1987. Nutritional ecology of arthropod gall-makers. pp. 235–258in Slansky, R., and Rodriguez, G. (Eds.), Nutritional Ecology of Insects, Mites and Spiders. Wiley, New York, NY.Google Scholar
Alexander, A. 1987. Compatibility of Picloram and the Tephritid Fly Urophora cardui for Canada Thistle (Cirsium arvense L.) Control. M.Sc. thesis, University of Saskatchewan, Saskatoon, SK. 95 + viii pp.Google Scholar
Andersen, P.C., and Mizell, R.F.. 1987. Physiological effects of galls induced by Phyloxera notabilis (Homoptera: Phyloxeridae) on pecan foliage. Environmental Entomology 16: 264–268.CrossRefGoogle Scholar
Bagatto, G., and Shorthouse, J.D.. 1991. Accumulation of copper and nickel in plant tissues and an insect gall of lowbush blueberry, Vaccinium angustifolium, near an ore smelter at Sudbury, ON, Canada. Canadian Journal of Botany 69: 1483–1490.CrossRefGoogle Scholar
Bagatto, G., Zmijowskyj, T.J., and Shorthouse, J.D.. 1991. Galls induced by Diplolepis spinosa influence distribution of mineral nutrients in the shrub rose. HortScience 26: 1283–1284.CrossRefGoogle Scholar
Bequaert, J. 1924. Galls that secrete honeydew. A contribution to the problem as to whether galls are altruistic adaptations. Bulletin of the Brooklyn Entomological Society 19: 101–124.Google Scholar
Bell, A.A. 1981. Biochemical mechanisms of disease resistance. Annual Review of Plant Physiology 32: 21–81.Google Scholar
Berube, D.E. 1978 a. The basis for host plant specificity in Tephritis dilacerata and T. formosa (Dipt:Tephritidae). Entomophaga 23: 331–337.CrossRefGoogle Scholar
Berube, D.E. 1978 b. Larval descriptions and biology of Tephritis dilacerata (Dip.: Tephritidae), a candidate for the biocontrol of Sonchus arvensis in Canada. Entomophaga 23: 69–82.CrossRefGoogle Scholar
Berube, D.E. 1980. Interspecific competition between Urophora affinis and U. quadrifasciata (Diptera: Tephritidae) for ovipositional sites on diffuse knapweed (Centaurea diffusa: Compositae). Zeitschrift für Angewandte Entomologie 90: 299–306.CrossRefGoogle Scholar
Berube, D.E., and Myers, J.H.. 1982. Suppression of knapweed invasion by crested wheatgrass in the dry interior of British Columbia. Journal of Range Management 35: 459–461.CrossRefGoogle Scholar
Bronner, R. 1992. The role of nutritive cells in the nutrition of cynipids and cecidomyiids. pp. 118–140in Shorthouse, J.D., and Rohfritsch, O. (Eds.), Biology of Insect-induced Galls. Oxford University Press, New York, NY.Google Scholar
Brewer, J.W., Bishop, J.N., and Skuhravy, V.. 1987. Levels of foliar chemicals in insect-induced galls (Dipt., Cecidomyidae). Zeitschrift für Angewandte Entomologie 104: 503–510.Google Scholar
Carlson, R.B., and Mundal, D.. 1990. Introduction of insects for the biological control of leafy spurge in North Dakota. North Dakota Farm Research 47(6): 7–8.Google Scholar
Cornell, H.V., and Hawkins, B.A.. 1993. Accumulation of native parasitoids on introduced herbivores: A comparison of hosts as natives and host invaders. The American Naturalist 141: 847–865.CrossRefGoogle ScholarPubMed
Crawley, M.J. 1989. The successes and failures of weed biocontrol using insects. Biocontrol News and Information 10: 213–223.Google Scholar
Dennill, G.B. 1987. The Biological Control of the Weed Acacia longifolia by the Gall Wasp Trichilogaster acaciaelongifoliae: A Study of a Plant–Insect Interaction. Ph.D. thesis, University of Cape Town, Cape Town. 468 pp.Google Scholar
Dennill, G.B. 1988. Why a gall former can be a good biocontrol agent: The gall wasp Trichilogaster acaciaelongifoliae and the weed Acacia longifolia. Ecological Entomology 13: 1–9.CrossRefGoogle Scholar
Dennill, G.B., and Gordon, A.J.. 1990. Climate-related differences in the efficacy of the Australian gall wasp Trichilogaster acaciaelongifolia (Hymenoptera:Pteromalidae) released for the control of Acacia longifolia in South Africa. Environmental Entomology 19: 130–136.CrossRefGoogle Scholar
Dowd, P.F., and Kok, L.T.. 1982. Parasitism of Rhinocyllus conicus in Virginia. Environmental Entomology 11: 71–77.CrossRefGoogle Scholar
Dreger-Jauffret, F., and Shorthouse, J.D.. 1992. Diversity of gall inducing insects and their galls. pp. 8–33in Shorthouse, J.D., and Rohfritsch, O. (Eds.), Biology of Insect-induced Galls. Oxford University Press, New York, NY.Google Scholar
Fay, D., Harnett, C.D., and Knapp, A.K.. 1993. Increased photosynthesis and water potentials in Siphium integrifolium galled by cynipid wasps. Oecologia 93: 114–120.CrossRefGoogle ScholarPubMed
Forsyth, S.F. 1984. Stress Physiology and Biological Control of Canada Thistle, Cirsium arvense (L.) Scop. Ph.D. thesis, McGill University, Montreal, PQ. 330 pp.Google Scholar
Fourcroy, M., and Braun, C.. 1967. Observations sur la galle de l'Aulax glechomae L. on Glechoma hederaceae L. II Histologie et rôle physiologique de la coque sclérifée. Marcellia 34: 3–30.Google Scholar
Glasser, W.G., and Kelley, S.S.. 1987. Lignin. Encyclopedia of Polymer Science and Engineering 8: 795–852.Google Scholar
Goeden, R.D., and Louda, S.M.. 1976. Biotic interference with insects imported for weed control. Annual Review of Entomology 21: 325–342.CrossRefGoogle Scholar
Graham, M.W.R. de V. 1969. The Pteromalidae of North Western Europe (Hymenoptera: Chalcidoidea). Bulletin of the British Museum (Natural History) Entomology Supplement. 352 pp.Google Scholar
Harris, P. 1979. The cost of biological control of weeds by insects in Canada. Weed Science 27: 242–250.CrossRefGoogle Scholar
Harris, P. 1980 a. Establishment of Urophora affinis Frfld. and U. quadrifasciata (Meig.) in Canada for the biological control of diffuse and spotted knapweed. Zeitschrift für Angewandte Entomologie 89: 504–514.CrossRefGoogle Scholar
Harris, P. 1980 b. Effects of Urophora affinis Frfld. and U. quadrifasciata (Meig.) (Diptera: Tephritidae) on Centaurea diffusa Lam. and C. maculosa Lam. (Compositae). Zeitschrift für Angewandte Entomologie 90: 190–210.CrossRefGoogle Scholar
Harris, P. 1991. Classical biocontrol of weeds: Its definition, selection of effective agents, and administrative-political problems. The Canadian Entomologist 123: 827–849.CrossRefGoogle Scholar
Harris, P., and Cranston, R.. 1979. An economic evaluation of control methods for diffuse and spotted knapweed in western Canada. Canadian Journal of Plant Science 59: 375–382.CrossRefGoogle Scholar
Harris, P., and Myers, J.H.. 1984. Centaurea diffusa Lam. and C. maculosa Lam. s. lat., diffuse and spotted knapweed (Compositae). pp. 127–137in Kelleher, J.S., and Hulme, M.A. (Eds.), Biological Control Programmes Against Insects and Weeds in Canada 1969–1980. Commonwealth Agricultural Bureaux, Farnham Royal, UK.Google Scholar
Harris, P., and Wilkinson, A.T.S.. 1984. Cirsium vulgare (Savi) Ten., bull thistle (Compositae). pp. 147–153in Kelleher, J.S., and Hulme, M.A. (Eds.), Biological Control Programmes Against Insects and Weeds in Canada 1969–1980. Commonwealth Agricultural Bureaux, Farnham Royal, UK.Google Scholar
Hartley, S.E., and Lawton, J.H.. 1992. Host-plant manipulation by gall-insects: A test of the nutrition hypothesis. Journal of Animal Ecology 61: 113–119.CrossRefGoogle Scholar
Hawkins, B.A. 1990. Global patterns of parasitoid assemblage size. Journal of Animal Ecology 59: 57–72.CrossRefGoogle Scholar
Hendel, F. 1927. Trypetidae. In Lindner, E. (Ed.), Die Fliegen der palaearktischen Region. Stuttgart Vol. 5, pp. 1–221 + 17 pl.Google Scholar
Hewett, E.W. 1977. Some effects of infestation on plants: A physiological viewpoint. The New Zealand Entomologist 6: 235–243.CrossRefGoogle Scholar
Hori, K. 1992. Insect secretions and their effect on plant growth, with special reference to hemipterans. pp. 157–170in Shorthouse, J.D., and Rohfritisch, O. (Eds.), Biology of Insect-induced Galls. Oxford University Press, New York, NY.Google Scholar
Ivanova, T.S. 1966. Biological control of mountain bluet (Acroptilon picridis C.A.M.). Izvestiya Academil Nauk Tadzhikoi SSR 2: 51–63. [In Russian. Translation—Translation Bureaux, Canadian Secretary of State No. 3793.]Google Scholar
Jankiewicz, L.S., Plich, H., and Antoszewski, R.. 1979. Preliminary studies on the translocation of 14C-labelled assimilates and 32PO43- towards the gall evoked by Cynips (Diplolepis) quercus-folii L. on oak leaves. Marcellia 36: 163–174.Google Scholar
Jenson, E.A. 1984. Data requirements for economic evaluation of a knapweed containment program. pp. 27–36in Lacey, J.R., and Fay, P.K. (Eds.), Proceedings of the Knapweed Symposium, Montana State University, Bozeman, MT.Google Scholar
Johnston, T.H., and Tryon, H.. 1914. Queensland: Report of the prickly-pear travelling commission, 1 November 1912 – 30 April 1914. Government Printer, Brisbane, Australia. 131 pp.Google Scholar
Julien, M.H. 1992. Biological Control of Weeds. A World Catalogue of Agents and their Target Weeds, 3rd ed. CAB International, Wallingford. 186 pp.Google Scholar
Kaar, W.E., Cool, L.G., Merriman, M.M., and Brink, D.L.. 1991. The complete analysis of wood polysaccharides using HPLC. Journal of Wood Chemistry and Technology 11: 447–463.CrossRefGoogle Scholar
Kirjanova, E.S., and Ivanova, T.S.. 1969. New species of Paranguina Kirjanova, 1955 (Nemotoda: Tylenchidae) on Tadzhikskoi. Ushcel's Kondara (Akademi Nauk Tadzhikskoi SSR) 2: 200–217. [In Russian. Translation—Translation Bureaux, Canadian Secretary of State.]Google Scholar
Klein, M., and Seitz, A.. 1994. Geographic differentiation between populations of Rhinocyllus conicus Frölich (Coleoptera, Curculionidae)—concordance of allozyme and morphometric analysis. Zoological Journal of the Linnean Society 110: 181–191.CrossRefGoogle Scholar
Kok, L.T., and Surles, W.W.. 1975. Successful biocontrol of musk thistle by an introduced weevil, Rhinocyllus conicus. Environmental Entomology 4: 1025–1027.CrossRefGoogle Scholar
Küster, E. 1911. Die Gallen der Pflanzen. Ein Lehrbuch der Botaniker und Entomologen. Hirzel Leizig.Google Scholar
Kutacek, M. 1991. Plant hormones as factors of morphogenesis and structural integrity in plants. pp. 13–117in Sebanek, J., Sladky, Z., and Prochazka, (Eds.), Experimental Morphogenesis and Integration of Plants. Elsevier, Amsterdam.Google Scholar
Lalonde, R.G., and Shorthouse, J.D.. 1982. Exit strategy of Urophora cardui (Diptera: Tephritidae) from its gall on Canada thistle. The Canadian Entomologist 114: 873–878.Google Scholar
Lalonde, R.G., and Shorthouse, J.D.. 1984. Developmental morphology of the gall of Urophora cardui (Diptera, Tephritidae) in the stems of Canada thistle (Cirsium arvense). Canadian Journal of Botany 62: 1372–1384.Google Scholar
Lalonde, R.G., and Shorthouse, J.D.. 1985. Growth and development of larvae and galls of Urophora cardui (Diptera: Tephritidae) on Cirsium arvense (Compositae). Oecologia 65: 161–165.CrossRefGoogle ScholarPubMed
Lamont, B. 1985. Host distribution, potassium content, water relations and control of two co-occurring mistletoe species. Journal of the Royal Society of Western Australia 68: 21–25.Google Scholar
Larson, K.C., and Whitham, T.G.. 1991. Manipulation of food resources by a gall-forming aphid: The physiology of sink-source interactions. Oecologia 88: 15–21.CrossRefGoogle ScholarPubMed
Lichter, J.P., Weis, A.E., and Dimmick, C.R.. 1990. Growth and survivorship differences in Eurosta (Diptera: Tephritidae) galling sympatric host plants. Environmental Entomology 19: 972–977.CrossRefGoogle Scholar
Littlefield, J.L. 1991. Parasitism of Rhinocyllus conicus Froelich (Coleoptera: Curculionidae) in Wyoming. The Canadian Entomologist 123: 929–932.CrossRefGoogle Scholar
Marsden, J.S., Martin, G.E., Parham, D.J., Riddsdill-Smith, T.J., and Johnston, B.G.. 1980. Returns on Australian Agricultural Research. Industries Assistance Commission, C.S.I.R.O, Canberra. 107 pp.Google Scholar
McCrea, K.D., Abrahamson, W.G., and Weis, A.E.. 1985. Goldenrod ball gall effects on Solidago altissima: 14C translocation and growth. Ecology 66: 1902–1907.CrossRefGoogle Scholar
Mead, R., and Curnow, R.N.. 1983. Statistical Methods in Agriculture and Experimental Biology. Chapman and Hall Ltd., New York, NY. 335 pp.Google Scholar
Meyer, J., and Maresquelle, H.J.. 1983. Anatomie des galles. Gebrüder Borntraeger, Stuttgart. 662 pp.Google Scholar
Miflin, B.J., and Lea, P.J.. 1977. Amino acid metabolism. Annual Review of Plant Physiology 28: 299–329.CrossRefGoogle Scholar
Moorby, J. 1977. Integration and regulation of translocation within the whole plant. pp. 425–454in Jennings, E.H. (Ed.), Integration of Activity in the Higher Plant. Cambridge University Press, Cambridge.Google Scholar
Muesebeck, C.F.W., Krombein, K.V., and Townes, H.K.. 1951. Hymenoptera of America North of Mexico. USDA, Washington, DC. 1420 pp.Google Scholar
Myers, J.H., and Harris, P.. 1980. Distribution of Urophora galls in flower heads of diffuse and spotted knapweed in British Columbia. Journal of Applied Ecology 17: 359–367.Google Scholar
Neish, A.C. 1960. Biosynthetic pathways of aromatic compounds. Annual Review of Plant Physiology 11: 55–80.CrossRefGoogle Scholar
Northcote, D.H. 1972. Chemistry of the plant cell wall. Annual Review of Plant Physiology 23: 113–132.CrossRefGoogle Scholar
Ou, X., and Watson, A.K.. 1992. In vitro culture of Subanguina picridis in Russian knapweed callus, excised roots and shoot tissues. Journal of Nematology 24: 199–204.Google ScholarPubMed
Ou, X., and Watson, A.K.. 1993. Mass culture of Subanguina picridis and its bioherbicidal efficacy on Acroptilon repens. Journal of Nematology 25: 89–94.Google ScholarPubMed
Owens, R.G., and Specht, H.N.. 1966. Biochemical alterations induced in host tissues by root-knot nematodes. Contribution from Boyce Thompson Institute 23: 181–198.Google Scholar
Paclt, J., and Hassler, J.. 1967. Concentration of nitrogen in some plant galls. Phyton 12: 173–176.Google Scholar
Paquette, L.C., Bagatto, G., and Shorthouse, J.D.. 1993. Distribution of mineral nutrients within the leaves of common dandelion (Taraxacum officinales) galled by Phanacis taraxaci (Hymenoptera: Cynipidae). Canadian Journal of Botany 71: 1026–1031.CrossRefGoogle Scholar
Pate, J.S. 1980. Transport and partitioning of nitrogenous solutes. Annual Review of Plant Physiology 31: 313–340.CrossRefGoogle Scholar
Pate, J.S. 1989. Synthesis, transport and utilization of products of symbiotic nitrogen fixation. pp. 65–134in Oulton, J.E., Romeo, J.T., and Conn, E.E. (Eds.), Plant Nitrogen Metabolism. Recent Advances in Phytochemistry. Plenum Press, New York, NY.CrossRefGoogle Scholar
Patrick, J.W. 1984. Photosynthetic unloading from seed coats of Phaseolus vulgaris L.: Control by tissue water relations. Journal of Plant Physiology 115: 297–310.CrossRefGoogle Scholar
Peschken, D.P. 1984. Sonchus arvensis L., perennial sow-thistle, S. oleraceus L., annual sow-thistle and S. asper (L.) Hill, spiny annual sow-thistle (Compositae). pp. 205–209in Kelleher, J.S., and Hulme, M.A. (Eds.), Biological Control Programmes Against Insects and Weeds in Canada 1969–1980. Commonwealth Agricultural Bureaux, Farnham Royal, UK.Google Scholar
Pate, J.S. 1990. The west is best—but not for Urophora cardui, (Tephritidae) a gall fly established in SK on Canada thistle. Proceedings of the Entomological Society of Saskatchewan 38: 30.Google Scholar
Peschken, D.P., and Derby, J.L.. 1992. Effect of Urophora cardui (L.)(Diptera: Tephritidae) and Ceutorhynchus litura (F.) (Coleoptera:Curculionidae) on the weed Canada thistle, Cirsium arvense (L.) Scop. The Canadian Entomologist 124: 145–150.CrossRefGoogle Scholar
Peschken, D.P., and Harris, P.. 1975. Host specificity and biology of Urophora cardui (Diptera: Tephritidae). A biocontrol agent for Canada thistle (Cirsium arvense). The Canadian Entomologist 107: 1101–1110.CrossRefGoogle Scholar
Peschken, D.P., and Johnson, G.R.. 1979. Host specificity and suitability of Lema cyanella (Coleoptera: Chrysomelidae), a candidate for the biological control of Canada thistle (Cirsium arvense). The Canadian Entomologist 111: 1059–1068.CrossRefGoogle Scholar
Peschken, D.P., Thomas, A.G., and Wise, R.F.. 1983. Loss in yield of rapeseed (Brassica napus, B. campestris) caused by perennial sowthistle (Sonchus arvensis) in SK and MB. Weed Science 31: 740–744.CrossRefGoogle Scholar
Philipson, W.R. 1942. Studies in the development of the inflorescence. 1. The capitulum of Bellis perennis L. Annals of Botany (London) 10: 257–270.CrossRefGoogle Scholar
Powell, R.D., and Myers, J.H.. 1988. The effect of Sphenoptera jugoslavica Obenb. (Col., Bupresitidae) on its host plant Centaurea diffusa Lam. (Compositae). Journal of Applied Entomology 106: 25–45.CrossRefGoogle Scholar
Ray, P.M. 1987. Principles of plant cell expansion. pp. 1–17in Cosgrove, D.J., and Knievel, D.P. (Eds.), Physiology of Cell Expansion During Plant Growth. American Society of Plant Physiologists, Rockville.Google Scholar
Robinson, M.A.H., Halevy, D. Galili, and Plaut, Z.. 1983. Distribution of assimilates in Gladiolus grandiflorus as affected by water deficit. Annals of Botany 51: 461–468.CrossRefGoogle Scholar
Roitberg, B.D. 1988. Comparative flight dynamics of knapweed gall flies Urophora quadrifasciata and U. affinis (Diptera: Tephritidae). Journal of the Entomological Society of British Columbia 85: 58–64.Google Scholar
Rowe, D.J., and Kok, L.T.. 1984. Potential of Rhinocyllus conicus to adapt to plumeless thistle, Carduus acanthoides, in Virginia. Virginia Journal of Science 35: 192–196.Google Scholar
Roze, L.D. 1981. The Biological Control of Centaurea diffusa Lam. and C. maculosa Lam. by Urophora affinis Frauenfeld and U. quadrifasciata Meigen (Diptera: Tephritidae). Ph.D. thesis, University of British Columbia, Vancouver, BC. 208 pp.Google Scholar
Sampson, M.G., and Ingraham, A.. 1990. Biological Control of Weeds in Nova Scotia. Nova Scotia Department of Agriculture and Marketing, Halifax, NS. 53 pp.Google Scholar
Schirman, R. 1981. Seed production and spring seedling establishment of diffuse and spotted knapweed. Journal of Range Management 34: 45–47.Google Scholar
Schroeder, D. 1974. The phytophagous insects attacking Sonchus spp. (Compositae) in Europe. pp. 89–96in Wapshere, A.J. (Ed.), Proceedings of the 3rd International Symposium on Biological Control of Weeds. Commonwealth Agricultural Bureaux, Farnham Royal, UK.Google Scholar
Seitz, A., and Komma, M.. 1984. Genetic polymorphism and its ecological background in tephritid populations (Diptera: Tephritidae). pp. 143–158in Wohrman, K., and Lordchke, V. (Eds.), Population Biology and Evolution. Springer-Verlag, Berlin.CrossRefGoogle Scholar
Sheldrake, A.R., and Northcote, D.H.. 1968. The production of auxin by autolysing tissues. Planta 80: 227–236.CrossRefGoogle Scholar
Shorthouse, J.D. 1980. Modification of the flower heads of Sonchus arvensis (family Compositae) by the gall former Tephritis dilacerata (order Diptera, family Tephritidae). Canadian Journal of Botany 58: 1534–1540.CrossRefGoogle Scholar
Shorthouse, J.D. 1989. Modification of flowerheads of diffuse knapweed by the gall inducer Urophora affinis and U. quadrifasciata (Diptera: Tephritidae). pp. 221–228in Delfosse, E.S. (Ed.), Proceedings of the VII International Symposium on Biological Control of Weeds, Instituto Sperimentale per la Patologia Vegetale, Rome.Google Scholar
Shorthouse, J.D., and Lalonde, R.G.. 1984. Structural damage by Rhinocyllus conicus (Coleoptera: Curculionidae) within the flowerheads of nodding thistle. The Canadian Entomologist 116: 1335–1343.CrossRefGoogle Scholar
Skuhravy, V., Skuhravy, M., and Brewer, J.W.. 1980. Evaluation of plant damage caused by 3 species of gall midges (Diptera: Cecidomyiidae). Zeitschrift für Angewandte Entomologie 90: 184–190.CrossRefGoogle Scholar
Staden, van J., and Bennet, P.H.. 1991. Effect of galling on assimilate partitioning in crofton weed (Ageratina adenophora). South African Journal of Botany 57: 128–130.Google Scholar
Stinner, B.R., and Abrahamson, W.G.. 1979. Energetics of the Solidago canadensis-stem gall insect-parasitoid guild interaction. Ecology 60: 918–926.Google Scholar
Story, J.M. 1976. A Study of Urophora affinis (Diptera: Tephritidae) Released on Spotted Knapweed in Western Montana. M.Sc. thesis, Montana State University, Bozeman, MT. 1–77 pp.Google Scholar
Story, J.M., Boggs, K.W., and Good, W.R.. 1988. Optimal timing of 2,4-D applications for compatibility with Urophora affinis and U. quadrifasciata (Diptera: Tephritidae) for control of spotted knapweed. Environmental Entomology 17: 911–914.Google Scholar
Story, J.M., Boggs, K.W., Good, W.R., Harris, P., and Nowierski, R.M.. 1991. Metzneria paucipunctella Zeller (Lepidoptera:Gelechiidae), a moth introduced against spotted knapweed: Its feeding strategy and impact on two introduced Urophora spp. (Diptera: Tephritidae). The Canadian Entomologist 123: 1001–1007.CrossRefGoogle Scholar
Story, J.M., Nowierski, R.M., and Bogs, K.W.. 1987. Distribution of Urophora affinis and U. quadrifasciata, two flies introduced for biological control of spotted knapweed (Centaurea maculosa) in Montana. Weed Science 35: 145–148.CrossRefGoogle Scholar
Stuart, N.W. 1938. Nitrogen and carbohydrate metabolism of kidney bean cuttings as affected by treatment with indoleacetic acid. Botanical Gazette 100: 298–311.Google Scholar
TAPPI. 1989. Acid-soluble Lignin in Wood and Pulp. Useful Method 250. Technical Association of the Pulp and Paper Industry, Atlanta, GA. 2 pp.Google Scholar
Thibodeau, P.D. 1985. Translocation of 14C-labelled Assimilates in the Urophora cardui (L.) (Diptera:Tephritidae) – Cirsium arvense (L.) Scop. (Compositae) Gall System. M.Sc. thesis, Laurentian University, Sudbury, ON. 115 pp.Google Scholar
Thorne, J.H. 1985. Phloem unloading of C and N assimilates in developing seeds. Annual Review of Plant Physiology 36: 317–343.CrossRefGoogle Scholar
Turner, C.T., Grissell, E.E., Cuda, J.P., and Casanave, K.. 1990. Microdontomerus anthonomi (Crawford) (Hymenoptera: Torymidae), an indigenous parasitoid of the introduced biological control insects Bangasternus orientalis (Capriomont) (Coleoptera: Curculionidae) and Urophora affinis Frauenfeld (Diptera: Tephritidae). Pan-Pacific Entomologist 66: 162–166.Google Scholar
Van Soest, P.J., Roberston, J.B., and Lewis, B.A.. 1991. Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74: 3583–3597.CrossRefGoogle Scholar
Varley, G.C. 1937. The life history of some trypetid flies with descriptions of the early stages (Diptera). Proceedings of the Royal Entomological Society of London A 12: 109–122.CrossRefGoogle Scholar
Waring, G.L. 1986. Galls in harsh environments. Proceedings of the Entomological Society of Washington 88: 376–380.Google Scholar
Waring, G.L., and Cobb, N.S.. 1992. The impact of plant stress on herbivore population dynamics. pp. 167–226in Bernays, E. (Ed.), Insect–Plant Interactions, Vol. IV. CRC Press, Boca Raton, FL.Google Scholar
Watson, A.K. 1980. The biology of Canadian Weeds. 43. Acroptilon (Centuarea) repens (L.) DC. Canadian Journal of Plant Science 60: 993–1004.Google Scholar
Watson, A.K. 1986 a. Host range of, and plant reaction to, Subanguina picridis. Journal of Nematology 18: 112–120.Google ScholarPubMed
Watson, A.K. 1986 b. Biology of Subanguina picridis, a potential biological control agent of Russian knapweed. Journal of Nematology 18: 149–154.Google ScholarPubMed
Watson, A.K. 1986 c. Morphological and biological parameters of the knapweed nematode, Subanguina picridis. Journal of Nematology 18: 154–158.Google ScholarPubMed
Watson, A.K., and Harris, P.. 1984. Acroptilon repens (L.) DC. Russian knapweed (Compositae). pp. 105–110in Kelleher, J.S., and Hulme, M.A. (Eds.), Biological Control Programmes Against Insects and Weeds in Canada 1969–1980. Commonwealth Agricultural Bureaux, Farnham Royal, UK.Google Scholar
Watson, A.K., and Renney, A.J.. 1974. The biology of Canadian weeds. 6. Centaurea diffusa and C. maculosa. Canadian Journal of Plant Science 54: 687–701.CrossRefGoogle Scholar
Wehling, W.F., and Piper, G.L.. 1988. Efficacy diminution of the rush skeletonweed gall midge, Cystiphora schmidti (Diptera: Cecidomyiidae), by an indigenous parasitoid. Pan-Pacific Entomologist 64: 83–85.Google Scholar
White, I.M., and Korneyev, V.A.. 1989. A revision of the western Palaearctic species of Urophora Robineae-Desvoidy (Diptera: Tephritidae). Systematic Entomology 14: 327–374.CrossRefGoogle Scholar
Wilson, J.W., and Wilson, P.M.W.. 1991. Effects of auxin concentration on the dimensions and patterns of tracheary elements differentiating in pith explants. Annals of Botany 68: 463–467.CrossRefGoogle Scholar
Woodburn, T.L. 1993. Host specificity testing, release and establishment of Urophora solstitialis (L.) (Diptera: Tephritidae), a potential biological control agent for Carduus nutans L., in Australia. Biocontrol Science and Technology 3: 419–426.CrossRefGoogle Scholar
Ziegler, H. 1986. Control of photosynthesis by variation of diffusion resistance in mistletoes and their hosts. Advances In Agricultural Biotechnology 19: 171–185.Google Scholar
Zwölfer, H. 1970. Investigations on the Host-specificity of Urophora affinis Frfld. (Diptera., Trypetidae). XXV. Commonwealth Institute of Biological Control, Delémont, Switzerland. 28 pp.Google Scholar
Zwölfer, H. 1976. Investigations on Sphenoptera (Chilstetha) jugoslavica Obenb. (Col. Buprestidae), a possible biocontrol agent of the weed Centaurea diffusa Lam. (Compositae) in Canada. Zeitschrift für Angewandte Entomologie 80: 170–190.Google Scholar
Zwölfer, H. 1979. Strategies and counterstrategies in insect population systems competing for space and food in flower heads and plant galls. Fortschritte der Zoologie 25: 331–353.Google Scholar
Zwölfer, H. 1985. Insects and thistle heads: Resource utilization and guild structure. pp. 407–416in Delfosse, E.S. (Ed.), Proceedings of the VI International Symposium on Biological Control of Weeds. Agriculture Canada, Vancouver, BC.Google Scholar
Zwölfer, H., and Arnold-Rinehart, J.. 1993. The evolution of interactions and diversity in plant–insect systems: The Urophora–Eurytoma food web in galls of Palaearctic Cardueae. In Schultze, E.D., and Mooney, H.A. (Eds.), Biodiversity and Ecosystems Function. Ecological Studies 99: 211–233.Google Scholar
Zwölfer, H., Englert, W., and Pattulo, W.. 1970. Investigations on the Biology, Population Ecology and the Distribution of Urophora cardui. Weed Projects for Canada, Progress Report 27: 17 pp. Commonwealth Institute of Biological Control.Google Scholar
Zwölfer, H., and Harris, P.. 1984. Biology and host specificity of Rhinocyllus conicus (Froel.) (Col., Curculionidae), a successful agent for biocontrol of the thistle (Carduus nutans). Zeitschrift für Angewandte Entomologie 97: 36–62.CrossRefGoogle Scholar
Zwölfer, H., and Preiss, M.. 1983. Host selection and oviposition behaviour in west-European ecotypes of Rhinocyllus conicus Froel. (Col., Curculionidae). Zeitschrift für Angewandte Entomologie 95: 113–122.CrossRefGoogle Scholar