Biology and Management of Clover Root Curculio (Coleoptera: Curculionidae)

Clover root curculio (Sitona hispidulus (F.)) (CRC) has become an economically important pest of alfalfa since the regulatory phase-out of carbofuran, methyl bromide, and other synthetic soil fumigants. Native to temperate Europe, the Middle East, and Asia, CRC was introduced to North America in the early 1900s and is now widespread across the U.S. Adult foliar herbivory is not typically economically important. However, severe root damage by larvae can result in secondary plant pathogen infections, leading to losses in forage quality, yield, and stand life. Monitoring efforts include sweep netting adults and soil sampling around the crown and roots of plants for eggs and larvae. Relationships between CRC densities and root damage as well as economic thresholds have yet to be established. Although several pyrethroids have been registered for use against CRC adults, they are not recommended due to potential non-target effects. Chemical controls have not been registered for use against the cryptic larval stage. This review discusses CRC identification, life history, biology, and ecology. Potential ecological management strategies (e.g., crop rotation, planting dates, resistant host varieties), biological control agents, and insecticide options are also described as key components of an integrated pest management program against CRC in U.S. alfalfa.