The aim of this study was to examine the disease development of quambalaria shoot blight, caused by the fungal pathogen Quambalaria pitereka, in plantation-grown spotted gum (Corymbia citriodora subsp. citriodora, C. citriodora subsp. variegata, C. henryi and C. maculata) in south-east Queensland, Australia. The results showed that native spotted gums are a primary source of inoculum followed rapidly by the production of secondary inoculum from infected trees in the plantation. The rate of spread and development of Q. pitereka within plantations increased exponentially over time as additional trees became infected and produced secondary inoculum. Spore concentration was shown to play an important role in disease development, with disease severity increasing with increasing disease incidence on individual trees and incidence across the plantation.