CK, I live in MD and we've had a pretty cool year up until now (including temps in the 60's last week). If I had to take a guess at this time it would Verticillium wilt. Fusarium tends to more prevalent in warmer soil. The big problem with both wilts is that there are no chemical (or natural) agents to deal with them. Both fungi can live for years in the soil. Your options are rather limited. One thing would be to not plant them in the same place the next year. Of course, if you're like me, that really isn't an option. A better option would be to plant varieties that are VFN resistant.
Dan - "Welcome back my friends to the show that never ends..." Emerson, Lake and Palmer - Karnevil #9