Thank you for contacting Ask Extension. After looking at your pictures, I do not believe that you have boxwood blight. There are no brown leaves nor black lesions on the stems. It is hard to determine with only looking at pictures, It could be Boxwood decline, leafminer or psyllids. Symptoms consist of weak and spindly plants. Dead or dying branches occur randomly in the bush. The older leaves drop prematurely, and the remaining foliage develops a yellow color.

There are many issues happening with boxwoods right now, and from your pictures, it is hard to determine the exact problem. I am including a publication so that you can look at the symptoms and maybe can see what symptoms are similar.https://www.canr.msu.edu/home_gardening/uploads/files/WhatsWrongWithMyBoxwood_DiagnosticGuide2026.pdf  You can also take a sample to MSU to determine what exactly it is. https://www.canr.msu.edu/pestid/ It is too early in the season for the caterpillars to be on the plant, or any of the leafminers or psyllids. You might want to just keep an eye out on it as the weather warms up and see what you have. And because of the cold, it is too early to treat anything at this point.

There is a new problem that involves the box tree moth. Which is a black and green caterpillar that is about 2" long and very visible if it is on your boxwoods.

Here are some publications for your reference. These references will also help you in identifying the problem as the weather warms. 

https://www.canr.msu.edu/home_gardening/uploads/files/WhatsWrongWithMyBoxwood_DiagnosticGuide2026.pdf

https://www.canr.msu.edu/ipm/uploads/files/Box%20Tree%20Moth%20Identification.pdf

https://www.misin.msu.edu/facts/detail/?project=NA&id=497

https://extension.umd.edu/resource/boxwood-identify-and-manage-common-problems/

https://extension.psu.edu/boxwood-diseases

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