I tried the smoke bomb and didn't get them all or didn't get them at all. There are a huge amount of gopher holes in my yard, but the areas that they are doing all the damage doesn't have any holes. Where they killed the plants, I dug up and about a foot down I see these tunnels (3) going all over the place. I placed the smoke bombs in and covered it up. A day later those garden thieves are at it again.