The level of pest infestation below which the cost of further reducing the pest population exceeds the additional revenue or value of other benefits such reduction would achieve. In the case of vectors of life-threatening diseases, the value of saving one human life may be thought to exceed the (probably very high) cost of eliminating the vector totally. This is rarely the case where the damage is purely economic (e.g. to a farm crop or stored goods). If the benefits under consideration are social (e.g. relative freedom from clouds of insects which are a nuisance but otherwise harmless) EIL is known as the aesthetic injury level.
Subjects: Ecology and Conservation.