Boxwood blight: Identify, know, and conquer

Boxwood blight is the latest in a long line of exotic plant diseases to threaten the horticulture industry in North America and Europe. The origin of boxwood blight is unknown. There are no reports of the causal fungus prior to the discovery of a then undescribed Calonectria species in the United Kingdom in the 1990s. A decade later, boxwood blight disease was widespread across Western Europe and New Zealand. The fall of 2011 marked the first disease sightings in North America. In this talk, we will present recent advances in the boxwood blight pathosystem in the areas of pathogen diversity, genomics and biogeography, host diversity and breeding for resistance, the host/pathogen interaction, and the development of new diagnostic methods. Tools brought to bear on this system include AFLP and SSR-based population studies of >500 isolates collected globally 1998–2013, comparative genomic analyses of fifteen diverse Calonectria pseudonaviculata isolates, and host diversity assessments using SEM, phylogenetic and SSR analyses. A suite of detection tools – including LAMP, conventional and real-time PCR – provide early pathogen detection, identification of mating gene frequencies, and identification of phenotypically diverse lineages. Collectively, findings from this work are beginning to provide a broader understanding of boxwood blight, and generate a toolkit of knowledge, resources and infrastructure needed to support long-term, cost effective disease management.