I have also treated my grubs with milky spore. That has been successful. But the earthworms remain so the moles have a fairly steady diet of those. Because we are surrounded by a bird sanctuary, I feel like poison worms is not an option. I have tried all sorts of traps and gadgets as well as 'natural' deterrents. I have only been successful in moving them around...not eliminating them. I put my plants in containers or surround them in protective wire but the moles still manage to wreck havoc with their root systems. Now grass is another issue. I cant find a way to stop the relentless tunneling.

Well, I would set up mole traps then. Not with the goal of eliminating them, just tamping down the numbers. We do that with chipmunks. We kill some every year but we haven't eliminated them. When the populations of prey get high compared to the predators, prey populations will come down naturally through disease and predation, unless you have a problem with your predator population. We had a lovely woods across the street with great horned owls nesting. Two years ago they logged all the big trees out of there, so now we will obviously have more problems with moles . . . when numbers are super high, that's when your system is out of whack. I would stop aiming for elimination and go more for lessening of the numbers. You might feel better about your successes then. I have the same problems with squirrels and woodchucks. We have to go to all kinds of lengths to keep them out of stuff, because it is not easy to trap and kill them in our suburban environment, and we also don't want to leave poisons around . . .

Just fyi, my good friend did his doctoral research on earthworms. They are not native to the US, so I wouldn't feel too bad about tamping down their numbers in any way I could as well. Perhaps switching more of your yard to natural woodsy or prairie type of landscaping might help. Highly fertilized lawns harbor all kinds of pests just by the nature of how they have to be managed . . . lots of nutrients and water to keep them looking like an unnatural green carpet . . .

Thanks! I appreciate the feedback. and like your approach. I think a new type of landscaping would be so cool!

Do cats ever eat moles? I know that pet cats are usually kept indoors these days but I wonder if a cat might make a difference? Or what about a dog that digs? Maybe a Dachshund or a Westie. I think they were bred to hunt small mammals, right?

You could try this, it has good reviews. I just bought some for my rose garden to keep voles away. https://www.harborfreight.com/solar-mole-chaser-94661.html