![]() ![]() ![]() More information about diseases of boxwood can be found in this page from Clemson Cooperative Extension:.Volutella fruiting bodies are salmon-colored, not white. Volutella Blight ( Volutella buxi) causes browing of foliage but infected plants do not have circular leaf lesions and lack black markings on stems.Secondary infection by Volutella blight ( Volutella buxi) or other pathogens may occur.Root system remains intact but it is not recommended to retain damaged plant material because the disease can spread to healthy plants. Boxwood blight is unsightly and can lead to near-complete defoliation.Under high humidity, white spore masses (sporodochia) may be visible on stem tissue and the undersides of leaves.Shoots with multiple dark brown or black lesions (cankers) that are diamond-shaped or linear.Foliage becomes blighted, turning light brown.Leaves develop brown spots with dark borders, often in a circular pattern, eventually expanding to cover the entire leaf. ![]() Prior to its discovery in the USA, boxwood blight was known in New Zealand, the UK and Europe since the 1990s.Since then, it has been found in many states in the east, as well as in Ohio, Oregon, and in Canada. This disease was first discovered in the USA in Fall 2011, on boxwood in Connecticut and North Carolina.Buxus sempervirens may be more susceptible than other species. Susceptibility of other plants in the Boxwood family (Buxaceae) is unknown. Laboratory tests by the Connecticut Agricultural Experiment Station indicate that the ground cover Pachysandra terminalis) is also susceptible. The causal fungus can remain alive in fallen leaves which can then serve as the source of infection for subsequent years.Scientific Name: Cylindrocladium pseudonaviculatum ( Cylindrocladium buxicola, Calonectria pseudonaviculata)Ĭommon Name: Boxwood Blight, Box Blight, Cylindrocladium box blight, blight disease of boxwood, boxwood leaf dropīoxwood species ( Buxus spp.), including cultivars, Sweet Box ( Sarcococca spp.). Repeated defoliation and dieback from stem cankers have killed small rooted cuttings in nursery propagation. (See images below.) The pathogen does not attack the roots, so larger plants may produce new leaves during the growing season but may lose ornamental value as defoliation becomes severe. The key symptoms that differentiate Boxwood Blight from other boxwood diseases, such as Volutella Blight and Macrophoma Leaf Spot, are numerous narrow black cankers (black streaks) that develop on the green stems. The first symptoms begin as leaf spots followed by rapid browning and leaf drop starting on the lower branches and moving upward in the canopy. Photo: Landis Lacey & Kelly Ivors, NCSU Dept. The disease is caused by a fungus called Cylindrocladium pseudonaviculatum (synonym: Cylindrocladium buxicola). It has now become more noticeable in Maryland landscapes. The rainy 2018 season greatly increased the spread of the disease. The first Maryland case of Boxwood Blight was confirmed on plants from a landscaper’s nursery in December, 2011. Since this first US report the disease has been identified in a number of northeastern states and also in Oregon, and British Columbia. The disease was also found in a Virginia nursery. In October 2011, the disease was found in North Carolina and Connecticut in both nursery and landscape plantings. Classic boxwood blight leaf spots Photo: Dave Clement PhD Box blight or boxwood blight has been causing defoliation of boxwoods throughout Europe since the late 1990’s. ![]()
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