Natural Pest Control
As far back as 3000BC in Egypt, cats were being used as a method of pest control to guard grain stores against rodents. In 1939 a survey uncovered that a population of cats could drastically lower the level of rats found in the area, however they could not completely destroy the rodents population. If however, the rats were baited using poisons and the like, cats could stop them from returning to repopulate the area. (or at least an area of approximately 45 meters)
Biological Pest Control
Biological pest control is the control of rodents via management of natural predators and parasites. For example: mosquitoes are often controlled by putting Bt Bacillus thuringiensis ssp. israelensis, a bacterium that infects and kills mosquito larvae, in local water sources. This treatment has no known side effects to either humans or the remaining ecology, and is perfectly fine to drink. The basic point of biological pest control is to completely eradicate a pest whilst inflicting very little damage to the surrounding ecosystem.
Mechanical Pest Control
Mechanical pest control is exactly what it sounds like, the use of hands on techniques and assistance from very basic equipment and devices. These protective devices create a barrier between plants and insects. An extremely simple of this is physically removing a weed from the ground. This is called tillage and is one of the oldest methods of weed control known to man.
Destroying Breeding Grounds
Proper waste management systems and removal of still water, eliminates the risk of many pest infestations. This is a good example of why third world countries are often riddled with disease causing insects and rodents. Garbage provides shelter for many unwanted pests and bacteria, as well as an area where still water may collect and create a mosquito breeding ground. Once again, this is why in first world countries you will see significantly less rats, cockroaches, mosquitoes, flies and other pests then if you were in a third world country. This is due to the poor garbage collection and disposal services provided in those countries.
In the past, some European countries local communities would gather together when stray dogs and cats became to numerous, round up and kill all the animals in which did not appear to have an owner. Some countries even deploy teams of rat catchers in which chase rats out of a field where they are killed with dogs and simple hand tools.