Without looking at the code or knowing what your doing and what not my guess is that...
You draw the texture.
You move and don't have new data in that place of the screen to replace the previous data so it repeats it.
What you need to do is clear the data that's in the screen buffer or whatever it's called that tells the screen to show something, Or you need to add a blank texture so that the screen knows not to just keep that previous texture in that space, but that it is empty.
That's my guess... though i can't help you on the code to fix it as that area is the area i have problems with and is why I use unity.