Assessment of mating types and resistance to metalaxyl of Canadian populations ofPhytophthora infestans in 1997

  • Fouad Daayf
  • H. W. (Budz) Platt


The distribution of A1 and A2 mating types, and of metalaxyl-sensitive (MS), metalaxyl-intermediate (MI), and metalaxyl-resistant (MR) strains ofPhytophthora infestans, the causal pathogen of late blight, were determined in Canada in 1997. Potato plants or tubers and tomato plants or fruits, suspected to have late blight infection, were received from seven Canadian provinces in 1997, and were assessed for the presence ofP. infestans. Among 220 samples suspected to have late blight,P. infestans was recovered from 132 samples (60%) received from British Columbia (BC), Manitoba, New Brunswick, Prince Edward Island, and Quebec. From the 132 samples, 364 isolates were obtained and tested for their mating type and response to metalaxyl. Populations ofP. infestans within Canadian provinces were homogeneous for mating types, except within BC, where populations comprised both A1 and A2 mating types both within fields and sometimes within samples. The A2 mating type was found in all provinces where late blight was present. The A1 mating type was found only in Manitoba (1 isolate) and in BC (38 isolates). Unlike the old A1 isolates, those found in BC in 1997 were highly resistant to metalaxyl. These A1 isolates are even more resistant than A2 isolates. Based on assays with 10−1 of metalaxyl, 14% of all tested isolates were MS, 69.8% were MI and 16.2% were MR. In addition, all provinces contained MS, MI, and MR isolates. No specific mating type or metalaxyl sensitivity level were specific to tomato or potato.

Additional Key Words

Late blight potato tomato Solanum spp. 

Literature cited

  1. Andrivon, D. 1997. Report of the discussions of the subgroup epidemiology. Pages 49–55In: 2nd workshop of an European network for development of an integrated control strategy of potato late blight, Carlow, Ireland, 24–27 Sept.Google Scholar
  2. Bruck, R.I., W.E. Fry, and A.E. Apple. 1980. Effect of metalaxyl, an acylalanine fungicide, on developmental stages ofPhytophthora infestons. Phytopathology 70: 597–601.CrossRefGoogle Scholar
  3. Carter, G.A., R.M. Smith, and K.J. Brent. 1982. Sensitivity to metalaxyl ofPhytophthora infestons populations in potato crops in southwest England in 1980 and 1981. Annu Appl Biol 100: 433–441.CrossRefGoogle Scholar
  4. Chycoski, C.I. and Z.K. Punja. 1996. Characteristics of populations ofPhytophthora infestans from potato in British Columbia and other regions of Canada during 1993 to 1995. Plant Dis 80: 579–589.Google Scholar
  5. Coffey, M.D. and L.W. Young. 1984. Responses to metalaxyl of sensitive and resistant isolates ofPhytophthora infestans. Phytopathology 74: 615–620.Google Scholar
  6. Cook, L.R. 1991. Current problems in the chemical control of late blight: the northern Ireland experience. Pages 337–348In:Phytophthora. JA Lucas, R.C. Shattock, D.S. Shaw, and L.R. Cook, eds. British Mycological Society, Cambridge University Press, Cambridge.Google Scholar
  7. Davidse, L.C., D. Looijen, L.J. Turkensteen, and D. Van Der Wal. 1981. Occurrence of metalaxyl resistant strains ofPhytophthora infestans in Dutch potato fields. Neth J Plant Pathol 87: 65–68.CrossRefGoogle Scholar
  8. Deahl, K.L., R.W. Goth, R. Young, S.L. Sinden, and M.E. Gallegly. 1991. Occurrence of the A2 mating type ofPhytophthora infestans in the United States and Canada. Am Potato J 68: 717–725.CrossRefGoogle Scholar
  9. Deahl, K.L., S.P. DeMuth, G. Pelter, and D.J. Ormrod. 1993a First report of resistance ofPhytophthora infestans to metalaxyl in eastern Washington and southwestern British Columbia. Plant Dis 77: 429.Google Scholar
  10. Deahl, K.L., D.A. Inglis, and S.P. DeMuth. 1993b. Testing for resistance to metalaxyl inPhytophthora infestans isolates from northwestern Washington. Am Potato J 70: 779–795.CrossRefGoogle Scholar
  11. Deahl, K.L., S.P. DeMuth, S.L. Sinden, and A. Rivera-Pena. 1995. Identification of mating types and metalaxyl resistance in North American populations ofPhytophthora infestans. Am Potato J 72: 3549.Google Scholar
  12. Dowley, L.J. and E. O’Sullivan. 1981. Metalaxyl-resistant strains ofPhytophthora infestans (Mont.) De Bary in Ireland. Potato Res 24: 417–421.CrossRefGoogle Scholar
  13. Dowley, L.J. and E. O’Sullivan. 1985. Monitoring metalaxyl-resistant strains ofPhytophthora infestans (Mont.) De Bary in Ireland. Potato Res 28: 531–534.CrossRefGoogle Scholar
  14. Fry, W.E. and S.B. Goodwin. 1997. Re-emergence of potato and tomato late blight in the United States. Plant Dis 81: 1349–1357.CrossRefGoogle Scholar
  15. Fry, W.E., S.B. Goodwin, J.M. Matuszak, L.J. Spielman, M.G. Milgroom, and A. Drenth. 1992. Population genetics and intercontinental migrations ofPhytophthora infestans. Annu Rev Phytopathology 30: 107–129.CrossRefGoogle Scholar
  16. Gallegly, M.E. and A.J. Galindo. 1960. Mating types and oospores ofPhytophthora infestans in nature in Mexico. Phytopathology 48: 274–277.Google Scholar
  17. Goodwin, S.B. 1997. The population genetics ofPhytophthora. Phytopathology 87: 462–473.CrossRefPubMedGoogle Scholar
  18. Goodwin, S.B., B.A. Cohen, K.L. Deahl, and W.E. Fry. 1994a. Migration from northern Mexico as the probable cause of recent genetic changes in populations ofPhytophthora infestans in the United States and Canada. Phytopathology 84: 553–558.CrossRefGoogle Scholar
  19. Goodwin, S.B., B.A. Cohen, and W.E. Fry. 1994b. Panglobal distribution of a single clonal lineage of the Irish potato famine fungus. Proc Nat Acad Sci USA 91: 11591–11595.PubMedCrossRefGoogle Scholar
  20. Goodwin, S.B., L.S. Sujkowski, AT. Dyer, B.A. Fry, and W.E. Fry. 1995. Direct detection of gene flow and probable sexual reproductionof Phytophthora infestans in northern North America. Phytopathology 85: 473–479.CrossRefGoogle Scholar
  21. Goodwin, S.B., L.S. Sujkowski, and W.E. Fry. 1996. Widespread distribution and probable origin of resistance to metalaxyl in clonal genotypes ofPhytophthora infestans in the United States and Canada. Phytopathology 86: 793–800.CrossRefGoogle Scholar
  22. Grinberger, M., D. Kadish, and Y. Cohen. 1989. Occurrence of the A2 mating type and oosporesof Phytophthora infestans in potato crops in Israel. Phytoparasitica 17: 197–204.Google Scholar
  23. Hohl, H.R. and K Iselin. 1984. Strains ofPhytophthora infestans from Switzerland with A2 mating type behaviour. Trans Br Mycol Soc 83: 529–530.CrossRefGoogle Scholar
  24. Holmes, S.J.I., and A.G. Shannon. 1984. Studies on metalaxyl-resistant strains ofPhytophthora infestans in potato crops in Southwest Scotland. Plant Pathol 33: 347–354.CrossRefGoogle Scholar
  25. Koh, Y.J., S.B. Goodwin, A.T. Dyer, B.A. Cohen, A Ogoshi, N. Sato, and W.E. Fry. 1994. Migrations and displacements ofPhytophthora infestans populations in east Asian countries. Phytopathology 84: 922–927.CrossRefGoogle Scholar
  26. Matuszak, J.M., J. Fernandez-Elquezabal, W.-K. Gu, M. Villareal-Gonzalez, and W.E. Fry. 1994. Sensitivity ofPhytophthora infestans populations to metalaxyl in Mexico: distribution and dynamics. Plant Dis 78: 911–916.Google Scholar
  27. Miller, J.S., P.B. Hamm, and D.A. Johnson. 1997. Characterization of thePhytophthora infestans population in the Columbia basin of Oregon and Washington from 1992 to 1995. Phytopathology 87: 656–660.CrossRefPubMedGoogle Scholar
  28. Pappas, A.C. 1985. Metalaxyl resistance inPhytophthora infestans on greenhouse tomatoes in Greece. Plant Pathol 34: 293–296.CrossRefGoogle Scholar
  29. Peters, R.D. 1998. Characterization of evolving populations ofPhytophthora infestans causing late blight of potato in Canada. Ph.D. thesis, The University of Guelph, ON, Canada, 305 pages.Google Scholar
  30. Peters, R.D., H.W. Platt, and R. Hall. 1998. Long-term survivalof Phytophthora infestans on liquid media prepared from autoclaved seeds. Can J Plant Pathol (in press).Google Scholar
  31. Shattock, R.C. 1988. Studies on the inheritance of resistance to metalaxyl inPhytophthora infestans. Plant Pathol 37: 4–11.CrossRefGoogle Scholar
  32. Shattock, R.C., D.S. Shaw, A.M. Fyfe, J.R. Dunn, K.H. Loney, and J.A. Shattock. 1990. Phenotypes ofPhytophthora infestans collected from England and Wales from 1985 to 1988: mating type, response to metalaxyl, and isoenzyme analysis. Plant Pathol 39: 242–248.CrossRefGoogle Scholar
  33. Sozzi, D. and T. Staub. 1987. Accuracy of methods to monitor sensitivity ofPhytophthora infestans to phenylamide fungicides. Plant Dis 71: 422–425.CrossRefGoogle Scholar
  34. Therrien, C.D., P.W. Tooley, L.J. Spielman, W.E. Fry, D.L. Ritch, and S.E. Shelly. 1993. Nuclear DNA content, allozyme phenotypes, and metalaxyl sensitivity ofPhytophthora infestans from Japan. Mycol Res 97: 945–950.Google Scholar

Copyright information

© Springer 1999

Authors and Affiliations

  • Fouad Daayf
    • 1
  • H. W. (Budz) Platt
    • 1
  1. 1.Crops and Livestock, Research CentreAgriculture and Agri-Food CanadaCharlottetownCanada

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