ABSTRACT
Biological control is simply the regulation of plant and animal numbers by natural enemies. In assessing the phenomenon of biological control, it can be viewed in three major aspects: its naturalistic dimension, the classic importation of natural enemies, and the preservation and augmentation of natural enemies. One of the key factors that has crippled the chemical control strategy has been its adverse effects on naturally-occurring biological control. In fact, as emphasis on integrated control research has increased, there has been an immense amount of study on naturally-occurring biological control. Classic biological control is largely directed against accidental invaders of new areas which attain epidemic abudance because of their escape from the natural enemies that restrain them in their native habitats. The great majority of classic biological control successes have involved insects. Several factors bear on the consideration of a weed's suitability for biological control and again, in part, there are differences from insect control.
