Discovery of the cause and relevance of a serious new eucalyptus foliar disease in Indonesia

Abstract

In the early 2010s, a seriously damaging leaf and shoot disease of unknown aetiology was observed in Eucalyptus plantations of North Sumatra, Indonesia. A decade-long investigation led to the identification of the causal agent of the disease, which was described as the new species Elsinoe necatrix. Elsinoe species cause scab diseases on plants and this new disease will now be known as Eucalyptus scab and shoot malformation. This is the first time that an Elsinoe sp. has been found infecting Eucalyptus trees grown for plantation forestry anywhere in the world. The genomes of a number of E. necatrix were sequenced making it possible to understand the reproductive biology and population genetics of this fungus. Research making up this thesis highlights the fact that E. necatrix, and other Elsinoe spp., could be emerging as important constraints to Eucalyptus plantation forestry. This study serves as a foundation to improve the currently limited understanding regarding the complex biology and epidemiology of a poorly understood, but significantly important group of plant pathogens.