ABSTRACT
In agriculture and forestry, insects are used as agents for the biological control of pests and weeds. Biological control takes advantage of antagonistic interspecific interrelations between the living organisms. The essence of biological control of insect pests lies in the restriction of their numbers to the economic threshold of injuriousness. This value for each pestiferous species is individually determined. Broadly speaking, weeds are plants that are undesirable on territories and water bodies that are used by humans for the economic activity. For example, about 2,200 species of economically significant weeds have been counted in the United States. Terrestrial weeds affect agriculture, cattle breeding, food industry and forest restoration. Aquatic weeds develop in lakes, storage reservoirs, rivers, irrigation and drainage canals, and other water bodies. They affect water transport, crop husbandry and fishery. The first attempt of using insects for biocontrol of aquatic weeds is the successful fight against the alligator weed in the United States in 1964.
