Biocontrol of boxwood blight by Trichoderma koningiopsis Mb2

Boxwood blight caused by Calonectria pseudonaviculata is an emerging destructive disease of great concern to horticulture and forest industries, public garden managers and homeowners across the globe. Current management strategies include use of less susceptible species and cultivars, chemical protection and sanitation practices. Here we report on isolation and identification of Trichoderma koningiopsis Mb2 from collapsing wild mushrooms for biocontrol of boxwood blight. The Trichoderma suppressed C. pseudonaviculata culture growth and controlled boxwood blight in a pre-treatment period dependent manner. Infection was reduced by 85% when Buxus sempervirens 'Suffruticosa' cuttings were challenged with the pathogen nine days after pre-treatment with Mb2. An extended interval of 18 or 36 days between pre-treatment and pathogen challenge was required to reduce disease incidence in containerized B. sinica var. insularis 'Justin Brouwers' plants by 54%-63%, respectively. Modes of action of Mb2 and the potential implications of these results are discussed.