What causes this green background in ls output?

There are two directories shown by 'ls'. Normally directories anywhere are blue on black background. But the first one is blue on green and impossible to read. Why is this? How to make it blue on black, or at least something light on something dark? This is on Ubuntu 12.04, using bash in Gnome Terminal. In Konsole, the blue is slightly darker, and possible to read, though could be way better.