Turn off touchpad when Mouse Plugged In

How can I turn off the touchpad on my laptop when I plug in a USB mouse? I can’t even disable it through the device manager… the “disable” button isn’t selectable. The only way I was able to turn it off was throught the BIOS, but this does me no good when I don’t have a mouse in (on the road).

Is there an app to do this?
I’ve googled but to no avail.