You will have to change that in the theme. Go to user preferences, and change ‘edge select’ to black. But note well that when in edge mode for example you will have selected but inactive edges also turned off! So you may not want that at all. I have not heard of this being a problem before… Maybe you just want to make the ‘vertex select’ a much brighter and different color than ‘edge select’, e.g my vertices are Blue and my edges are orange, or maybe make the vertex size bigger (in the same place).