Abstract

Relative susceptibility of 23 Eucalyptus provenances of 11 species to pink disease 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 eucalypts giving susceptible response were affected significantly by the culture filtrates at low dilutions, whereas those giving resistant response tolerated high concentration with little damage to shoots. Responses to CS1 and CS2 culture filtrates were significantly different on various eucalypts, possibly indicating that the isolates are of two different strains. Criticisms of cut-shoot bioassay and its significance in laboratory screening of eucalypts to pink disease are discussed