Pachysandra Species and Cultivar Susceptibility to the Boxwood Blight Pathogen, Calonectria pseudonaviculata

Abstract

This research was conducted to answer grower questions regarding potential differences among Pachysandra species and cultivars in susceptibility to the boxwood blight pathogen, Calonectria pseudonaviculata. Five cultivars of P. terminalis, one cultivar of P. axillaris, and one selection of P. procumbens were evaluated using whole plants and detached leaves. Pachysandra species and cultivars differed somewhat in susceptibility to boxwood blight, with more significant differences observed between species and cultivars using whole plants than with detached leaf assays. All Pachysandra species and cultivars were susceptible to the pathogen and sporulation occurred on lesions; therefore, all of these cultivars may serve as inoculum reservoirs for the boxwood blight pathogen. Best management practices will need to take this into account in landscapes, garden centers, and nurseries to prevent additional spread of the pathogen.