Suffice it to say that using terriers underground, and giant running dogs above ground, is among the slowest, most expensive, and least efficient ways of getting rid of fox and wolves.
Traps and poisons are extremely efficient, however, and there have always been many methods of each, from pits, snares, leghold gins, and baited hooks, to arsenic, strychnine, sodium fluroacetate, and carbon monoxide gassing of underground natal dens.
One of the oldest poisons used on fox and wolves, is wolfsbane, which is made from a broad class of flowers in the Aconitum family. Various species of this member of the buttercup family can be found all over the world, from Asia to Europe, and from the New World to Africa.
In "De Materia Medica," Dioscorides advises that Akoniton lycoctonum is particularly useful for killing panthers, wolves, and other wild beasts. In truth, many species of Aconitum have been used for centuries to tip arrows and spears used to used to kill everything from deer, ibex, musk ox, tigers and bears to wild dogs.
Aconitum plants contain the relatively fast-acting poison Aconitine which targets the cardiovascular and central nervous system. Death from wolfsbane poisoning generally occurs when the heart slows and then stops. Aconitine is very bitter, so is only rarely ingested, but it can easily kill if a reduction is consumed or put in contact with a wound. If anyone is concerned because I am (horrors!) talking about a kind of ancient, difficult-to-make, and hard-to-dispense poison, please relax. The pest shelf at your local HomeDepot is the thing to fear -- there is enough modern stuff there to knock out a city block!