An American farmer has grown so tired of feral pigs - or hogs - destroying his crops that he has begun machine-gunning them down.

Skip Smith from the Texas town of Dublin uses night vision goggles and a machine gun with a silencer as his preferred method of pest control.

"One of the problems with watermelon crops is having feral hogs come in, they were brought in by the Spanish to quell the rattlesnakes back in the 1800s and they mated with regular domestic hogs and now we have a feral hog problem," he told Radio National.

"There is a 93-day gestation period, they have 13 piglets within 93 days, so those 13 piglets after two months have another 13 piglets and so they'll tear up a sorghum [field] or a wheat field in a matter of a night ... half an acre to an acre."

He says farmers usually use dogs to chase the pigs or trap them before shooting them, but he takes a different approach.

"We use thermal imaging and night vision so they can't see us, hear us or anything like that and it's a very effective way. It's the same thing that our forces use in Iraq, we're just using them on animals," he said.

Once found he then uses a range of guns to shoot the pigs.

"It matters [sic] from H and K or Heckler and Koch or Bushmasters or Colts - they are fully automatic, cartridge-loaded machine guns," he said.

"Then we have regular suppressed guns that are fully suppressed, that are as loud as you and I talking. So a .338 Lapua, which is a very large cartridge would sound like a decibel of 35 which we are talking at right now."

He admits he could just use a hunting rifle, but the sound alerts other pigs.

"It makes too much noise and when the rifle goes off the pigs will scatter so you have a better chance of getting more with this type of a situation," he said.

He says when hunting he usually kills five or six pigs at a time, but can get up to eight if the silenced guns are used.

"We shoot about 45 to 50 a week on 1,000 acres," he said.

"This is on our property and neighbours will ask us [onto their property] especially when wheat comes up they [pigs] will tear up a field like craters, like mortars went off - it's incredible."

Mr Smith also trades machine guns and fishing gear, and jokes that if anyone tried to stop farmers around Texas using their guns to control pests there would be a rebellion.