Killing crabgrass/fescue in my still dormant bermuda
 

My bermuda lawn is still dormant, but will probably start growing very soon.

Some places in the yard, however, have nice green crabgrass or fescue patches
that have sprouted up from neighbor's yard (or some other reason).

Question: Can I safely use grass killer spray on the green grass and not hurt
the dormant bermuda? I think these work by coating the green part of the leaf
and thereby getting into the root, which shouldn't happen with the bermuda since
it's not actively growing, right?