Cyphocleonus achates(Fahraeus) is a root-feeding weevil introduced from Eurasia for biological control of spotted knapweed,Centaurea maculosaLamarck, in Montana and other areas of the northwestern United States. BecauseC. achatesis flightless and univoltine, distribution of the weevil throughout the vast infestations of spotted knapweed in Montana and the northwestern United States will be extremely slow. To hasten the distribution of this promising weevil, a propagation effort using field corrals was initiated at the Western Agricultural Research Center in Corvallis, Montana. Procedures for propagating the weevil in field corrals are described. The direct cost of rearing 1000C. achatesadults for field release was $1634, an average of $1.63 per insect. Labor comprised 83% of the total direct cost. The described field-corral approach is effective and the cost appropriate for providingC. achatesfor initial colonization in the western United States.