The adults emerge in July and seek overwintering sites under new musk thistle rosettes, ground litter or wooded areas, where they will remain dormant until the following spring. Flower head weevils usually produce only one generation per year. It also undergoes one generation per year. Adult weevils emerge from summer dormancy in early October. They feed on the underside of rosette leaves by puncturing leaf tissue.
Females lay eggs during the fall and on warm days during the winter.
These same adults overwinter and resume egg laying the following spring, up until about May 1. In late spring some egg laying occurs in secondary buds. Adult musk thistle rosette weevil. Musk thistle rosette infested with rosette weevil larvae. Larvae complete their development then leave the rosette and pupate in the soil.