Ceratocystis pirilliformis was first described from wounds on Eucalyptus trees in Australia
and subsequently found as a common wound inhabitant on these trees in South Africa.
During a recent disease survey carried out to identify Ceratocystis species infecting tree
wounds in South Africa, C. pirilliformis was isolated from various tree species, including a
native Rapanea species and two non-native hosts, Acacia mearnsii and E. grandis growing in
the Western Cape Province. These new collections from the Western Cape Province, together
with isolates of C. pirilliformis previously collected from Eucalyptus species in the eastern
part of the country, provided the opportunity to investigate the possible movement of the
pathogen since it was first recorded in South Africa. The identity of newly collected isolates
of C. pirilliformis was confirmed using DNA sequence comparisons using partial β-tubulin
and TEF-1α gene regions. Microsatellite markers were screened on a collection of C.
pirilliformis isolates from the Western Cape Province. Results showed that this population
has higher levels of population genetic estimates such as private allele frequency, allelic
richness and gene diversity. Inoculation tests were performed to determine whether C.
pirilliformis is a pathogen of A. mearnsii, which is planted as an important plantation forestry
tree in the country. All isolates were shown to be highly virulent. Results of the study
consequently revealed that C. pirilliformis has a wider host range and geographic distribution
in South Africa than previously recognized and that it is a potentially important pathogen of