The study of insects that have a direct influence on humanity. Though this includes beneficial as well as harmful species, most attention is devoted to the latter and how they become pests and are controlled. The emphasis on managing harmful insects reflects the immediacy and seriousness of pest problems, particularly the destruction of agricultural products and the transmission of disease. These are highly visible problems, whereas the benefits gained from useful insects are, in most cases, not so clearly understood or so well documented economically.