ESTABLISHMENT OF LARINUS-MINUTUS GYLLENHAL (COLEOPTERA, CURCULIONIDAE) FOR BIOLOGICAL-CONTROL OF DIFFUSE AND SPOTTED KNAPWEED IN THE WESTERN UNITED-STATES

Larinus minutus Gyllenhal (Coleoptera: Curculionidae) is a capitulum-i nfesting natural enemy of diffuse and spotted knapweed (Centaurea diff usa Lamarck and C. maculosa Lamarck) (Asteraceae). United States Depar tment of Agriculture, Animal and Plant Health Inspection Service, Plan t Protection and Quarantine personnel and research collaborators relea sed 13,791 adults from 1991 to 1993 for the biological control of thes e knapweeds. Weevil establishment was confirmed in Montana in 1992, an d in Washington and Wyoming in 1993. Redistribution began in 1994 from one site each in Montana, Washington, and Wyoming. As of 1994, L. min utus had also been released in Minnesota, Nebraska, Oregon, and Utah f or a total of seven states and 24 counties.