The practise of using beneficial natural organisms to attack and control harmful plant and animal pests and weeds is called biological control, or biocontrol. This can include introducing predators, parasites, and disease organisms, or releasing sterilised individuals. Biocontrol methods may be an alternative or complement to chemical pest control methods. Biocontrol is part of the Animal and Plant Health Inspection Service programme to control several economically important pests of food and fibre crops; it also is researched and used by other USDA agencies that promote integrated pest management.