ABSTRACT
The integrity of many natural environments in the southeastern United States is being threatened by invasive plants. Biological control offers a selective method for the control of these weeds because the insects and diseases it employs effect few if any nontarget species. This contribution evaluates the suitability of the biological control method for 19 invasive weeds. Criteria that can help predict the number of natural enemies associated with a weed are: (1) size of the plant’s native range, (2) commonness of the plant in its native range, (3) number of congeneric species in the world, (4) and the natural enemies already known. Criteria that help predict conflicts with valued plants, which can limit the biological control approach, are the number of congeneric species and important economic relatives the United States. The relative seriousness of the weed (not examined here), and the degree to which practical controls exist, determine the need for biological control.