I found this information in one of the publications I read. I thought you might be interested in what is happening in with the plant world.
A new fungal disease was first identified in North America, October, 2011. It has been found in 9 states and Canada (CT, MA, MD, NC, NY, PA, OR, RI, VA, United States and B.C, Canada). This fungus, Boxwood Blight or Box Blight (Cylindrocladium buxicola) effects all varieties of boxwood and pachysandra. It spreads quite rapidly and requires warm, humid conditions to survive.
Boxwood Blight can exist, undetected, on healthy plants. It survives and is transmitted though contact with infected leaves and cankers. It can travel very long distances, thousands of miles, through the transport of infected plants from nursery to nursery, infected tools and clothing. It is also transmitted through splashing water from overhead watering and rain.
Symptoms are leaf defoliation and death, which can often look similar to many other boxwood diseases or problems. If you suspect your plants are infected, it is recommended to have your boxwood analyzed by a lab to determine actual causes of symptoms your boxwood may be facing. Our local University Extension offices would be able to analyze samples you may have (http://pddc.wisc.edu/).
Because it is a new disease, there are many unknowns. It is not yet clear how weather (growing degree days, relative humidity, and relative leaf wetness) affect spore production. It is also unknown what kind of weather increases or decreases spore production or how many spores it takes to trigger an infection.
As researchers study this fungal disease, they will uncover more information about how to best control Boxwood Blight infections. Field and greenhouse research will help determine best timing for fungicide application and which fungicides will manage the disease.
Currently, researchers are recommending two fungicides, which have been studied under laboratory conditions, that homeowners can use. These fungicides are chlorothalonil and mancozeb. I cannot stress enough; caution is required in using these products as they have been found effective in lab results only…not in field studies!
All is not lost to the boxwood world! The National Arboretum has partnered with the USDA Mycology and Microbiology Lab to breed disease resistant boxwood varieties. The National Arboretum is well positioned to take on such a project. They hold the National Boxwood Collection which has 266 unique plants 178 different varieties and 52 different wild species.
If you would like to learn more, I have included two very informative links.