In Buxus disease, Box Blight? Problem with box topiary I wrote about a new, at the time the latest, buxus problem in our garden. Now, about three years later, we know that this is a problem that is here to stay and will not easily go away.
In 2002, the cause of a new box blight disease was confirmed to be a new fungal species called Cylindrocladium buxicola. Box blight caused by Cylindrocladium buxicolais (also Pseudonaviculatum Volutella buxi) is now widespread throughout The Netherlands and Europe. In The Netherlands it was first seen around 2005 where the genetic-group G2 was identified. The fungus now pops up around the globe so be warned!
An important mode of spread of the disease in gardens has been through the introduction of apparently healthy Buxusmaterial carrying the disease into gardens or nurseries. Nurseries have access to a wide range of fungicides that may suppress the disease rather than killing the fungus. If the fungus stops spreading this photo shows the end-result in close-up.
This new fungus proved resistant to most of the agents available of which only few are available to consumers like us.
I now started using a new fungicide developed by Bayer. It is named Bayer Twist plus spray and has double agents: 0,125 g/l tebuconazool and 0,125 g/l trifloxystrobine.
This is not meant to promote this stuff but rather to inform you that it is available and may also be a solution to your problem. Well, the latter has yet to be proven in our garden, but still.
It is important to sanitize equipment and tools regularly and to separately destroy infected debris. Although one advice is to maintain adequate spacing between plants to promote air circulation, that is no option for us.
This article in the Journal of Plant Pathology (2008), 90 (3), 581-584 describes the disease and its spread throughout Europe.