European Journal of Plant Pathology

, Volume 115, Issue 2, pp 215–222 | Cite as

Occurrence and distribution of resistance to QoI fungicides in populations of Podosphaera fusca in south central Spain

  • D. Fernández-Ortuño
  • A. Pérez-GarcíaEmail author
  • F. López-Ruiz
  • D. Romero
  • A. de  Vicente
  • J. A. Torés


Cucurbit powdery mildew caused by Podosphaera fusca limits crop production in Spain. Since its management is strongly dependent on chemicals, the rational design of control programmes requires a good understanding of the fungicide resistance phenomenon in field populations. Fifty single-spore isolates of P. fusca were tested for sensitivity to three quinone-outside inhibiting (QoI) fungicides: azoxystrobin, kresoxim-methyl and trifloxystrobin. Minimum inhibitory concentration (MIC) values for QoI-sensitive isolates were found to range from 0.25 to 10 μg ml−1 for azoxystrobin to 5–25 μg ml−1 for kresoxim-methyl, using a leaf disc-based bioassay. High levels of cross-resistance to QoI fungicides were found. Eleven isolates showed resistance to the three QoI fungicides tested with MIC and EC50 values >500 μg ml−1 resulting in RF values as high as >715 and >1000 for trifloxystrobin and azoxystrobin, respectively. A survey of P. fusca QoI resistance was carried out in different provinces located in the south central area of Spain during the cucurbit growing seasons in 2002, 2003 and 2004. Examination of a collection of 250 isolates for QoI resistance revealed that 32% were resistant to the three fungicides tested; the provinces of Ciudad Real, Córdoba and Murcia being the locations with the highest frequencies of resistance (44–74%). By contrast, no resistance was found in Badajoz, and relatively low frequencies were observed in Almería and Valencia (10–13%). Nearly 50% of resistant isolates were collected from melon plants. Based on these data, recommendations about the use of QoI fungicides for cucurbit powdery mildew management in the sampled areas are made.


chemical control Cucurbitaceae fungicide resistance powdery mildew fungi Qo-inhibitors strobilurins 


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This study was funded by grants from Plan Nacional de Recursos y Tecnologías Agroalimentarias of Ministerio de Educación y Ciencia, Spain (AGL2001-1837 and AGL2004-06056). The authors thank M.T. MacGrath (Cornell University) for critical reading of the manuscript and I. Cánovas (EE La Mayora) for excellent technical asistance. The authors also thank M. Bardin (INRA Montfavet) and N. Fanourakis (TEI Heraklion) for kindly providing French and Greek reference P. fusca strains.


  1. Álvarez B, Torés JA (1997) Cultivo in vitro de Sphaerotheca fuliginea (Schlecht. ex. Fr.), efecto de diferentes fuentes de carbono sobre su desarrollo Boletín de Sanidad Vegetal Plagas 23: 283–288Google Scholar
  2. Anke T, Oberwinkler F, Steglich W, Schramm G (1977) The strobilurins-new antifungal antibiotics from the basiomycete Strobilurus tenacellus Journal of Antibiotics 30: 806–810PubMedGoogle Scholar
  3. Anon. (2005) International FRAC QoI Working Group Minutes ( Scholar
  4. Bartlett DW, Clough JM, Godwin JR, Hall AA, Hamer M, Parr-Dobrzanski B (2002) The strobilurin fungicides Pest Management Science 58: 649–662PubMedCrossRefGoogle Scholar
  5. Becker WF, von Jagow G, Anke T, Steglich W (1981) Oudemansin, strobilurin a, strobilurin b, and myxothiazol: new inhibitors of the bc1 segment of the respiratory chain with an e-β-methoxy-acrylate system as common structural element FEBS Letters 132: 329–333PubMedCrossRefGoogle Scholar
  6. Bohr VA, Anson RM (1999) Mitochondrial DNA repair pathways Journal of Bioenergetics and Biomembranes 31: 391–398PubMedCrossRefGoogle Scholar
  7. Braun U (1987) A monograph of the Erysiphales (powdery mildews) Beiheftezur Nova Hedwigia 89: 1–700Google Scholar
  8. Braun U, Cook TA, Inman AJ, Shin H-D (2002) The taxonomy of powdery mildew fungi. In: Bélanger RR, Bushnell WR, Dik AJ, Carver TLW (eds.) The Powdery Mildews. A Comprehensive Treatise. APS Press, St. Paul, MN (pp 13–55)Google Scholar
  9. Brent KJ and Hollomon DW (1998) Fungicide resistance: The assessment of risk. FRAC Monograph No. 2. GCPF, BrusselsGoogle Scholar
  10. Del Pino D, Olalla L, Pérez-García A, Rivera ME, García S, Moreno R, de Vicente A, Torés JA (2002) Occurrence of races and pathotypes of cucurbit powdery mildew in southeastern Spain Phytoparasitica 30: 459–466Google Scholar
  11. Délye C, Corio-Costet MF (1998) Origin of primary infections of grape by Uncinula necator: RAPD analysis discriminates two biotypes Mycological Research 102: 283–288CrossRefGoogle Scholar
  12. Gisi U, Sierotzki H, Cook A, McCaffery A (2002) Mechanisms influencing the evolution of resistance to Qo inhibitor fungicides Pest Management Science 58: 859–867PubMedCrossRefGoogle Scholar
  13. Heaney SP, Hall AA, Davies SA, Olaya G (2000) Resistance to fungicides in the QoI-STAR cross-resistance group: current perspectives. Proceedings, BCPC Conference-Pests and Diseases. Brighton, UK (pp. 755–762)Google Scholar
  14. Ishii H, Fraaije BA, Sugiyama T, Noguchi K, Nishimura K, Takeda T, Amano T, Hollomon DW (2001) Occurrence and molecular characterization of strobilurin resistance in cucumber powdery mildew and downy mildew Phytopathology 91: 1166–1171CrossRefGoogle Scholar
  15. Keinath AP, DuBose VB (2004) Evaluation of fungicides for prevention and management of powdery mildew on watermelon Crop Protection 23: 35–42CrossRefGoogle Scholar
  16. Kraiczy P, Haase U, Gencic S, Flindt S, Anke T, Brand U, Von Jagow G (1996) The molecular basis for the natural resistance of the cytochrome bc1 complex from strobilurin-producing basidiomycetes to center Qo inhibitors European Journal of Biochemistry 235: 54–63CrossRefGoogle Scholar
  17. McGrath MT (2001) Fungicide resistance in cucurbit powdery mildew: Experiences and challenges Plant Disease 85: 236–245CrossRefGoogle Scholar
  18. Olalla L (2001) Etiología, biología y epidemiología del oídio de las cucurbitáceas en cultivos bajo plástico. PhD thesis, Universidad de Málaga, MálagaGoogle Scholar
  19. Pérez-García A, Mingorance E, Rivera ME, del Pino D, Romero D, Torés JA, de Vicente A (2006) Long-term preservation of Podosphaera fusca using silica gel Journal of Phytopathology 154:190–192CrossRefGoogle Scholar
  20. Sitterly WR (1978) Powdery mildew of cucurbits. In: Spencer DM (ed.) The Powdery Mildews. Academic Press, London (pp 359–379)Google Scholar
  21. Texeira de Sousa JA (1985) Lutte contre Rosellinia necatrix (Hartig) Berlese, agent du “pourridié laineux”: Sensibilité de quelques espèces végétales et lutte chimique European Journal of Forest Pathology 15: 323–332CrossRefGoogle Scholar
  22. Torés JA, Cánovas I, Velasco MV (1990) Nota sobre Sphaerotheca fuliginea (Schlecht. ex Fr) Poll., agente causante del oídio de las cucurbitáceas en la zona costera de las provincias de Málaga y Almería Investigación Agraria 5: 475–479Google Scholar
  23. Zitter TA, Hopkins DL, Thomas CE (1996) Compendium of cucurbits diseases. APS Press, St. Paul, MNGoogle Scholar

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • D. Fernández-Ortuño
    • 1
  • A. Pérez-García
    • 2
    Email author
  • F. López-Ruiz
    • 1
  • D. Romero
    • 2
  • A. de  Vicente
    • 2
  • J. A. Torés
    • 1
  1. 1.Estación Experimental “La Mayora” (CSIC)MálagaSpain
  2. 2.Grupo de Microbiología y Patología Vegetal-Unidad Asociada a CSIC, Departamento de Microbiología, Facultad de CienciasUniversidad de MálagaMálagaSpain

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