Noxious Weeds - Biological Control Agents
Biological weed management involves the use of a living organism to control weeds. There are three insect species established on the Refuge. They include: root-mining moth (Agapeta zoegana), root-mining weevil (Cyphocleonus achates), and the seed head fly (Terellia virens.). Insect populations and plant community responses are monitored by the Western Agricultural Research Center located in Corvallis, Montana. Both Agapeta zoegana and Cyphocleonus achates and have established healthy populations at the release site. According to Research Professor Jim M. Story, data suggest that these two insects are causing a reduction in knapweed, biomass, number of stems per plant, plant height, and the number of mature plants per unit area.
In addition, the musk thistle seed head weevil (Rhinocyllus conicus) is strongly established throughout the Bitterroot Valley as well as the refuge. This insect has proven to be effective in reducing seed production.
Biological Control Agents