Devastating Fungal Disease Found in Michigan

The fungal disease, Boxwood blight has been detected in Michigan according to the Michigan Department of Agriculture and Rural Development.  Responsible for causing over $3 million in damages during the first year of detection in Connecticut, the importance of this pathogen cannot be overstated. Boxwood (Buxus sp.) is one of the more popular woody plants in landscapes and accounts for a significant portion of nursery sales within the state. One of the reasons this disease-causing fungus is able to spread undetected is that is can lie dormant in transported nursery stock and in Christmas wreaths containing boxwood sprigs. 

Picture showing defoliation of Boxwood caused by Calonectria pseudonaviculata. Image taken by Joan Allen, UConn (UCONN CAHNR , 2016)

Boxwood blight is caused by the fungus, Calonectria pseudonaviculata, in the phylum Ascomycota. This fungus spreads via spores which are spread a short range by wind and rain. The primary means of long-distance fungal spread is related to human activity such as the transportation of plant material. If a boxwood plant in the landscape is showing signs of this disease, it should be removed to prevent further spread of this pathogen. 


UCONN CAHNR (2016). Boxwood Blight. Retrieved from University of Connecticut PSLA & Extension:

Raven, B. (2018, Dec 11). ‘Serious fungal disease’discovered in Michigan for first time. Retrieved from MLIVE:


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