This involves the use of natural pest enemies as biological control agents. For example, bacteria of the species Bacillus thuringiensis are used to combat mosquitoes, within the “Natura” network of nature protection areas within the European Union, where the use of chemical biocide formulations is prohibited. Biological formulations involve predators, parasitoids, pathogens (viruses, fungi, protozoa, bacteria) parasites and nematodes.