Pathogenicity to Three Agricultural Plant Species of Phytophthora drechsleri Isolates From Australian Forest Communities

Abstract

The pathogenicity of 35 isolates of Phytophthova dvechsleri obtained from native forest and other sources throughout Australia was examined, with Carthamus sp., Helianthus sp. and Citrullus sp. as the test hosts.

Fourteen southern and 20 northern ecotypes of the fungus were pathogenic to Carthamus but not to Helianthus or Citrullus; a single isolate of the A¹ mating strain was non-pathogenic to all three hosts.

The relevance of these findings to agriculture and forestry is discussed.