boxwood disease I believe is boxwood blight
For several years I have lost about a dozen sufrucicosa sempirverens. If possible I would like to send a sample if you provide a mailing address and the cost to evaluate the sample. Several of my bushes seemed to shed all its leaves but after spraying an anti fungal ( Daconil ) to all my bushes ( boxwoods) there seem to be some improvement. I am not sure I am doing the right treatment but the bushes with the rapid drop releaved themselves although sparsely so far. I also fed them with Epsom this fall hoping to strengthen them. can you share with me what you think it might be? The long row of bushes you show in one of your pictures seem to be what I am seeing at my home. What replacment bushes should I buy to replace the ones that have died? I am thinking Buxus wintergreen variety Korean would be the most likely replacement which seems to ball up and not need yearly trimming.....Regards....Joe Lambert P.S. I can send pics if you would prefer and please tell me what I should use to treat them with.
I am sorry about your boxwood. You don't say where you are located, but I am in Arlington and the address of our offices are below. If you have not already done so please check all of the information here at the Boxwood Blight Task Force webpages. https://ext.vt.edu/agriculture/commercial-horticulture/boxwood-blight.html
At this site you will find easy to use info about controls, look alike problems, boxwood replacements, and more. If you would like to bring in a sample to be tested, at VA Tech, your local Extension office can help you with that. The FAQs are particularly useful. Also they identify Chlorothanonil as the mail fungicide for homeowner use.
Typically the cost is only to cover postage to Blacksburg if that. Samples should be brought to your local extension office in double bagged plastic.
They should be of the branch that is showing the transition of the disease from healthy to diseased wood All on one branch. Do not put wet paper towels or anything like that in the bag and try to bring it in on a monday or a tuesday so the lab can get it in a timely fashion . Be sure to fill out the diagnostic form here and bring that with you. https://www.pubs.ext.vt.edu/450/450-097/450-097.html
I would be happy to look at pictures if you are not in the Arlington Alexandria area. Please also include a closeup of the twig/branch looking for elongated black lesions, and the leaves looking for the telltale black fungal leaf spot.
Take care not to infest other yards or other plants in your yard.