Relative susceptibility of 23 Eucalyptus provenances of 11 species to pink disease caused by Corticium salmonicolor was assessed in culture filtrates of two isolates (CS1 from E. tereticornis and CS2 from E. grandis) of the pathogen, employing cut-shoot bioassay. The results showed statistically significant variation in response among different provenances within a species. Cut shoots of eucalypus giving susceptible response were affected significantly by the culture of filtrates at low dilutions, whereas those giving resistant response tolerated high concentration with little damage to shoots. This evidence clearly indicated an interaction between the host and culture filtrates of the pathogen. The response of CS1 and CS2 culture filtrates gave statistically significant differences in their reactions on various eucalypts, possibly indicating that the isolates are of two different strains. The criticism of cut-shoot bioassay and its significance in laboratory screening of eucalypts to pink disease are discussed. {\textcopyright} 1988.