[Ecosystems with special reference to development of resistance]

Pests and ectoparasites may cause considerable damage to health or impair the well-being of humans and domestic animals in the open as well as indoors. They may do so as vectors of diseases, producers of allergens and/or toxins and also as causes of repulsion and nuisances. Further detrimental factors of their occurrence may consist e.g. in damage to foods and feeds as well as materials used for insulation of apparatus, textiles, packaging materials, wood etc. In addition, measures to control pests and parasites may affect the habitats of non-target animals, e.g. larvicides applied to liquid manure, or products to control breeding of mosquitoes and blackflies. Such measures may result in hazards for surface water, ground water and soil from residues of the products applied. In the indoor environment, the users of rooms may become exposed, over extended periods, to contamination resulting from the desorption of insecticides or acaricides from the material treated. Increasing and often complex resistance to the active ingredients of the products used means a qualitative and quantitative intensification of the generation of residues. To be able to minimize such problems, exact knowledge of type, spectrum, intensity and dynamics of the resistance presence are required. However, systematic inquiries into the problem are not conducted in the Federal Republic of Germany.