Purple loosestrife is a list A species in Colorado which means that it is scheduled for eradication and biological control is an inappropriate control method. More information on Purple Loostrife.
The Colorado Department of Agriculture does rear biocontrol agents for purple loosestrife as part of a nationwide cooperative program. Hylobius transversovittatus is a large weevil that develops within the roots of purple loosestrife. They require one to two years to develop on plants but at the Insectary they are reared on an artificial diet where they can go from egg to adult in just ten weeks. These weevils have been shipped from Colorado to new homes in several other states.