title: Effects of fungicides on in vitro spore germination and mycelial growth of the phytopathogens Leptosphaeria maculans and L. biglobosa (phoma stem canker of oilseed rape).
abstract: BACKGROUND
  Phoma stem canker, caused by the coexisting related fungal pathogens Leptosphaeria maculans (Des.) Ces. & de Not and L. biglobosa Shoemaker & H Brun, is a major disease of winter oilseed rape in the UK. Annually, over 90% of UK crops receive at least one foliar application of fungicide, but little is known about the sensitivity of the more damaging L. maculans and the less damaging L. biglobosa to these fungicides. The effects of flusilazole, tebuconazole and Methyl Benzimidazole Carbamate (MBC) fungicides (benomyl and carbendazim) on the germination of ascospores, conidia and germ tube growth of both species were examined. Isolates collected from different oilseed rape crops in England and Wales were assessed for their mycelial growth on fungicide-amended medium, and ED(50) values were calculated.
  
  
  RESULTS
  Leptosphaeria maculans and L. biglobosa differed in their sensitivity to fungicides. Conidial germination of L. maculans was more sensitive to these fungicides than that of L. biglobosa. Isolates of L. maculans had smaller ED(50) values for mycelial growth for all fungicides tested than isolates of L. biglobosa.
  
  
  CONCLUSIONS
  These results suggest that fungicide applications might affect the structure of L. maculans/L. biglobosa populations in UK winter oilseed rape crops.
authors.affiliation: Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Maria R
authors.initials: MR
authors.lastname: Eckert
authors.forename: Stephen
authors.initials: S
authors.lastname: Rossall
authors.forename: Andrew
authors.initials: A
authors.lastname: Selley
authors.forename: Bruce D L
authors.initials: BD
authors.lastname: Fitt
mesh_terms: D001203:Ascomycota / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology*; D029741:Brassica rapa / Q000382:microbiology; D002626:Chemistry, Pharmaceutical; D004305:Dose-Response Relationship, Drug; D005659:Fungicides, Industrial / Q000494:pharmacology*; D018525:Germination / Q000187:drug effects*; D025282:Mycelium / Q000187:drug effects* / Q000254:growth & development*; D010935:Plant Diseases / Q000382:microbiology; D013172:Spores, Fungal / Q000187:drug effects* / Q000502:physiology
chemical_list: D005659:Fungicides, Industrial