Abstract
Nonnative invasive plants (weeds) negatively impact native biodiversity, ecosystem services, agriculture, and the economic interests and health of humans. Since 1902, biological weed control has been employed as a cost-effective and sustainable management option for weeds in the USA. However, biological control is not appropriate for all weeds, nor is sufficient funding available to develop biological control for all weed species. Researchers in South Africa recently developed a Biological Control Target Selection (BCTS) system as an objective, transparent, and simple approach to prioritizing weeds as targets for biological control. The system includes multiple attributes pertaining to the: (1) impact and importance of the target weed, (2) likelihood of achieving success, and (3) investment required to develop and implement biological control. Attributes are scored based on available literature, and the overall score for each weed is used to rank species according to their potential to result in successful biological control programs. This paper describes the adaptation of the BCTS for application to weeds in the western USA not already targeted for biological control.