Reference

Cyphocleonus achates - Wikipedia Cyphocleonus achates is a species of true weevil known as the knapweed root weevil. Cyphocleonus achates "knapweed root weevil". "Comparison of Larval Development and Overwintering Stages of the Spotted Knapweed Biological Control Agents Agapeta zoegana (Lepidoptera: Tortricidae) and Cyphocleonus achates (Coleoptera: Curculionidae) in Montana Versus Eastern Europe". Impacts of the biological control agent Cyphocleonus achates on spotted knapweed, Centaurea maculosa, in experimental plots. "Influence of herbivory and competition on invasive weed fitness: observed effects of Cyphocleonus achates (Coleoptera: Curculionidae) and grass-seeding treatments on spotted knapweed performance" (PDF). "Effect of Summer Drought Relief on the Impact of the Root Weevil Cyphocleonus achates on Spotted Knapweed". Evaluation of establishment of Cyphocleonus achates and its potential impact on spotted knapweed.

The knapweed root weevil, Cyphocleonus achates (Fahraeus) (Coleoptera: Curculionidae), is consid- ... known to be sensitive to disturbance linked to cattle and horse grazing; Johnston and MacDonald (1967) have suggested that maintenance of this habitat type in climax condition may be impossible if subjected to grazing pressure. Grass-Seeding

Impacts of the biological control agent Cyphocleonus achates on spotted knapweed, Centaurea maculosa, in experimental plots - ScienceDirect The root weevil Cyphocleonus achates was introduced into western Montana in 1988 as a biological control agent against spotted knapweed (Centaurea maculosa), an exotic invasive weed from Eurasia. achates specifically has only been examined in Eurasian knapweed plants of the diploid type (Müller-Shärer et al., 2004, Ochsmann, 2001); C. Effects of site characteristics and release history on establishment of Agapeta zoegana (Lepidoptera: Cochylidae) and Cyphocleonus achates (Coleoptera: Curculionidae), root-feeding herbivores of spotted knapweed, Centaurea maculosa Abundances and interactions among biological control insects and their effects on target invasive plants were monitored within the flower heads and roots of diffuse knapweed, Centaurea diffusa, and in spotted knapweed, Centaurea stoebe, along the Colorado Front Range.