I had roaches and fleas in a fixer I bought and a good cleanup of the filthy yard, then poisoning got rid of them. I spread something like dianazon around the yard. I don’t think you can buy that anymore either.
TG, As you probably know the gophers migrate to wet soil if they are not there already and that they pop up every few feet. I put a clean perimeter around my vegetable garden so I can see them coming towards it. This way you get a chance at dealing with them on less than prime real estate.
You can also use large pavers, about 18″x18″, by standing them up, end to end in a trench, leaving just enough showing to make an attractive and sturdy border for whatever it is you are trying to protect. It isn’t perfect, but that plus some vigilance will work. If one climbs across the border and digs in( which won’t happen often), you know it is in a confined space and you can use the hose or what ever you want to go after it. They can hide from water by climbing up into a raised part of the tunnel system and watching the pretty river go by. I got rid of one last year, that I knew was confined to a small area, by making a probe that I could inject water into the surrounding areas with. You can feel a give when the probe finds a tunnel and turn the water on. I think it drowned, not sure, but the damage ,which was happening to a huge pumpkin plant, stopped and the pest never re-appeared.
