| Abstract: | Field and glasshouse inoculation tests with isolates of S. cardinale and S. unicorne (Cke & Ell.) Sutton on C. macrocarpa and C lusitanien showed symptoms caused by the two pathogens to be indistinguishable. Isolates of S. cardinale showed an overall higher pathogenicity and less variability than those of S. unicorne. Neither pathogen seemed capable of infecting hosts outside the Cupressaceae, An isolate of Boesewinkel originating from Crvptowcria and supposed to be a distinct species from the anamorph of Lepteutypa cupressi, failea to infect Cryptomeria; neither could L. cupressi and S. cardinale, though all of them readily infected C. macrocarpa and C. lusitanica. Isolates of S. unicoene showed vast differences in pathogenicity in any one test, but many of the Isolates also showed extremi pathogenicity variation between repeat tests, hence pathogenicity determination became uncertain or probalistic. There is no evidence that the decline of S cardinale in this country is due to reduced pathogenicity or to possible interaction with S. unicorne in host infection. |
