Sunflower Headclipping Weevil: Appearance, Territory, Damage and Life Cycle

Latin Name: Haplorhynchites Aeneus

Appearance: Haplorhynchites aeneus, often known as the head-clipping weevil or sunflower Headclipping weevil, is a leaf rolling weevil belonging to the Attelabidae family of beetles. It is native territory is North America. The sunflower as an adult the Headclipping weevil (Haplorhynchites aeneus) is about 5/16 inch long and lustrous black. Larvae are cream-colored, C-shaped, and resemble grubs. This is a black weevil with a curled snout and wing coverings that are quite soft. The specific shape of the plant damage is most easily used to make a diagnosis. Adults girdle flower peduncles and leaf petioles, causing partly cut blooms or leaves to dangle from the plant. When cut flower heads are opened, mating aggregations of adult weevils coated in pollen are frequently revealed.

Hosts Plants: Although sunflowers are the favorite plant, the weevil also kills purple coneflowers and other aster species.

Territory: North America

Damage Insect Cause: This bug normally impacts just a tiny fraction of plants in a field, mainly inside border rows, and treatment is rarely necessary. If 10% or more of the flower heads have been trimmed and adult weevils are still active in the field, treatment should be considered. Sunflower moth applications usually provide some control of head-clipping weevils.

Life History and Habits: There is just one generation each year, with adults often emerging on sunflowers around July when they approach reproductive phases. If flower buds are not yet present, weevils may cut leaf petioles. The trimming activity is assumed to be unique to females. Weevils spend a lot of time and energy severing heads, which may serve to diminish their appropriateness for other flower-feeding insects that might otherwise compete with larvae for the resource. Weevil pairs are regularly observed mating and feasting on pollen within the cut heads while still hanging on the plant. Eggs are placed in the dangling head; however, they are not considered to hatch until the head falls to the earth.  Developing larvae feed on disintegrating tissues, eventually exiting the head to overwinter as adult larvae in the earth. Pupation and adult emergence occur the following summer.