Sporothrix eucalypti (M.J. Wingfield et al. 1993) and Ramularia (De Beer et al. 2006).
Quambalaria eucalypti causes leaf and shoot blight on susceptible Eucalyptus spp. Lesions are often produced on actively growing shoots and young leaves, resulting in shoot malformation and leaf distortion. Heavy infections can cause shoot death, leading to loss of apical dominance and stunting. May also cause sunken black cankers on the stems (Roux et al. 2006). Under humid conditions, white spore masses form within the lesions.
Quambalaria is a basidiomycete that is a part of the Quambalariaceae, a unique family in the order Microstromatales. It is part of the smut fungi group (Ustilaginomycota). Quambalaria eucalypti infects the shoots, leaves and stems of Eucalyptus causing lesions and producing characteristic white powdery spore masses (Roux et al. 2006).
Infection by Q. eucalypti begins on young leaves and stem tissue. Conidial germination is triggered by high humidity, with penetration occurring via the stomata or wounds on the leaf surface or juvenile stems. Chlorotic spots develop within five days of infection, with necrotic lesions developing on leaves and new shoots in as little as seven days. Conidiophores and conidia can be present (as powdery white spore masses) on the shoots of infected plants approximately 14 days after infection. Quambalaria eucalypti has a rapid disease cycle (Pegg et al. 2009).
Crous PW, Wingfield MJ, Cheewangkoon R, Carnegie AJ, Summerell BA, Edwards J, Taylor PWJ, Groenewald JZ. 2019. Foliar pathogens of eucalypts. Studies in Mycology 94: 125-298.
Pegg GS, Web RI, Carnegie AJ, Wingfield MJ, Drenth A. 2009. Infection and disease development of Quambalaria spp. on Corymbia and Eucalyptus species. Plant Pathology 58: 642 – 654.
Roux J, Mthalana BL, de Beer ZW, Eisenberg B, Wingfield MJ. 2006. Quambalaria leaf and shoot blight on Eucalyptus in South Africa. Australasian Plant Pathology 35: 427-433.
Wingfield MJ, Crous PW, Swart WJ. 1993. Sporothrix eucalypti (sp. nov.), a shoot and leaf pathogen of Eucalyptus in South Africa. Mycopathologia 123: 159–164.
