Tips for effective use of victor black box gopher traps

I thought we had a peace treaty but recently the gophers completely girdled my beloved meyer lemon and decades old fig tree beyond recovery.

Does anyone have any pointers for effective use of these traps:
Victor Black Box Gopher Trap

I have had success in the past but recently on the hunt again and they keep getting backfilled with soil.

Should the entire hole be covered with something like cardboard so its dark all? Or should some light be visible at the end of the trap and just gentle cover other gaps where light could penetrate? Just not sure if I want light penetrating or to emulate their tunnel. Does anyone find bait to be helpful?

Thanks everyone,
Blaise

Hey Blaise. Sad about your trees. That's a declaration of war.

We probably duel with somewhat different species, but with the northern pocket gopher it's air movement that draws them to the trap, not light.

That said, my luck in my parents' garden has been minimal. They go down in 3' of hard clay and emerge in the beet patch. And I can't find the usual horizontal run to set the trap. Am I smarter than a flea-bitten rodent? Apparently the jury is out ... I'm working on it.

Don't cut down your girdled trees yet! Maybe you can save them by bridge grafting: Below a video showing the process with apples