I know several farmers who tell me if you pipe Anhydrous Amonia down the hoes you will have no more dirt pigs.
I’d just like to reiterate the PURE carbon dioxide method. I recall from a Geology class in took in college, that there was this small village directly below an active volcanoe in a valley. Well the volcanoe began spewing large amounts of ash and carbon Dioxide into the air. Well the CO2 settled into the valley and killed everyone in the village. it displaced all the air in the valley and filled it with the carbon dioxide killing everyone by suffocating them. If you could get your hands on a large amount of compressed CO2, and “flooded” the tunnels with it, it would most certainly slowly sink into the holes and eventually displace the air that is down there. I Imagine that you would need a considerable amount of the stuff to cover acres of terrain, but several large well placed tanks bleeding CO2 into the holes just migh be sufficient to suffocate the little whistle pigs.
I’m assuming you’re talking about the following situations that were not necessarily related to an eruption of the volcano.
"Much if not all of the CO2 released was stored in the lake prior to the event. Accumulation of CO2 in the lake starts when CO2-rich gas of magmatic origin rises to the earth’s surface and contacts groundwater; the CO2-charged groundwater is then discharged into the bottom of the lakes in springs. Oxygen and hydrogen isotope data plus the relative proportions of solutes in springs surrounding Lake Nyos suggest a common origin for ground and lake water. This common origin is consistent with the hypothesis of groundwater transfer of dissolved CO2 into the lake. In addition, measured values of 18O and 2H indicate that evaporative concentration is not responsible for the greater concentrations of major ions in Lake Nyos relative to other Cameroonian crater lakes. Post-event depth profiles of major ions imply that stable stratification existed before the release, and that only partial mixing of lake waters occurred during the release. Therefore, before the gas events these lakes were strongly stratified (surface and bottom waters do not mix), which allowed the gas that was being input in CO2-charged springs to buildup in the bottom waters of the lakes.
The trigger mechanism responsible for the gas release from the lake is unknown but has received much speculation. We know of no data that require as explanation a single, specific trigger mechanism. In fact, if the partial pressure of CO2 (PCO2 ) levels were near saturation prior to the event, almost any physical process common in lakes could have moved water vertically enough to cause local oversaturation and thus initiate the release."
If you problem persists, I understand predator urine works very well on pests.
And remember, to most animals, you are a predator.
The story comes to mind of a farmer who peed around his garden to keep the deer away. Very effective for him, but not for the Buddists down the road. They were vegatarians.
My $.02?
Bar B Q. Invite the guys over for a barbeque and kegger with the understanding that everyone pees in the holes of your enemies.
Could be fun.
More later,
Vahktang
I’d just like to say that I can’t believe this thread is still around. 
First of all, great thread.
I have done a little bit of research- very little- and a question has occurred to me- is there any way from a distance to tell apart a male and female groundhog? If so, shooting the females will kill off the colony, albiet slowly. Since the gophers only give birth once a year, being able to eliminate the female population would have a far greater effect than killing off the males. If they are not normally distinguishable, you may be able to identify pregnant ones, depending on when they breed.
Disturbing and slow, but the best way to keep this population under control without resorting to extraordinary means.
Good luck.
carpoon:
I do not distinguish between the sexes while commiting genocide. Any groundhog I see, I try to make into a dead groundhog regardless of race, creed, color, gender, or sexual preference.
I’m an equal opportunity asassin.
Spazo
I know that this thread is just for fun but anhydrous is not to be played with. It is serious stuff. Serious burns blindness and even death may result from an accident. My father in law spent many days in the hospital with burns from his shoulders down from an accident. He had worked with the stuff for years and then the improbible happened.
PS I still like traps.
hmm, and you wonder why coyotes havent moved into the area…
I’m in ecology right now at my college, and we just had a very long discussion about how the eradication of the groundhog is leading to the extinction of the coyote.
I recommend a nuke. Ya can’t go wrong with a good old fashioned nuke.
Let’s see em dig deep enough for that!
Alas and alack, it is time for this thread to go to retirement. It’s starting to get pretty big, and I don’t want to kill it by overposting.
One of the greats. Off to the Great Domain of Locked Threads.