Sunflower Stem Weevil – Cylindrocopturus adspersus

Sunflower Stem Weevil (Cylindrocopturus adspersus)

Latin Name: Cylindrocopturus adspersus

Common Name: Sunflower Stem Weevil


  • The sunflower stem weevil is a pale, speckled weevil with a short, curled snout held downwards beneath the skull.
  • Adults are enigmatic and secretive, darting around the other side of a stalk or dropping it in response to disturbance.
  • Larvae are cream-colored and can be detected by breaking stalks longitudinally to their root with a stout-bladed knife.

Host plants: Sunflowers


Throughout North America

Damage caused by Sunflower Stem Weevil:

The sunflower stem weevil causes debilitated stems and accommodation. The eggs will then spend the winter here. The larvae of the sunflower stem weevil will eat a tunnel in the stalk on their journey to the ground to pupate. This is especially true for sunflowers that the drought has harmed. The female weevil will lay her eggs in little gaps chewed into the lowest section of the stem. This insect spreads the ailments of Phoma black stem and charcoal rot.

Life history and Habits:

The sunflower stem weevil has only one generation. In the High Plains, it emerges in late May to early June, while in the northern plains; it emerges in mid to late June. The bottom stem is where the eggs are laid. The larvae begin feeding in the pit area of the stem shortly after hatching, and in August, they descend to the lower section of the stem to build an overwintering chamber.