We have several areas of pachysandra beds that are affected by some sort of blight. From what I have I think it many be a fungus, but wanted to see if you have any more information. What treatment would you recommend? Was thinking of a systemic as well as a topical product (Fungonil and Mancozeb) alternating weeks.
This is a fungal disease known as volutella, which is very common in old pachysandra beds where plant debris has built up in the bed and the fungus is encouraged by the resulting damp environment. http://extension.umd.edu/hgic/volutella-dieback-pachysandra-groundcover
The easiest thing to do is mow the bed, rake out all the debris, and let it send up new growth, which it will quickly do in the spring. Pachysandra is so tough, they can take a lot of abuse. It shouldn't need any fungicides.
You also may want to take this opportunity to plant some other plants in the areas that are already bare. Native ferns would do well. Japanese pachysandra is, obviously, not native so it is a sterile environment as far as adding to the ecosystem. In fact, when it gets into parks and natural areas it is very destructive. It is considered a non-native invasive plant in Maryland.