Indications of Susceptibility to Calonectria pseudonaviculata in Some Common Groundcovers and Boxwood Companion Plants

Knowing the host range of a pathogen is critical to developing and implementing effective disease management programs. ( ) is known to attack a number of species, varieties, and cultivars in the genus as well as three species ( , , and ) and several species, all in the Buxaceae family. The objective of this study was to evaluate non-Buxaceae groundcovers and companion plants commonly associated with boxwood plantings for their susceptibility to . Twenty-seven plant species belonging to 21 families were exposed to different levels of inoculum: 50 to 300 conidia per drop for detached leaf assays and 30,000 to 120,000 conidia per 1 ml for whole-plant assays. Inoculated plants were incubated in humid environments for at least 48 h to facilitate infection. infection and sporulation were observed on 12 plant species: , , , × , , , , , , , , and . These results suggest that there may be more hosts of commonly grown in nurseries and landscapes. If corroborated by observations of natural infection, these findings have implications for the Boxwood Blight Cleanliness Program instituted by the National Plant Board and for planning disease mitigation at production and in the landscape.